WorldWideScience

Sample records for high-pt neutral pions

  1. Photoproduction of neutral pions

    OpenAIRE

    Fuhrer, Andreas

    2009-01-01

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single neutral pion on the proton. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes at one loop are given. The relation of the phase of the electric multipole E_0+ to the phase of the S...

  2. Single neutral pion production by charged-current $\\bar{\

    CERN Document Server

    Aliaga, L; Bercellie, A; Bodek, A; Bravar, A; Brooks, W K; Butkevich, A; Caicedo, D A Martinez; Carneiro, M F; Christy, M E; Chvojka, J; da Motta, H; Devan, J; Dytman, S A; Díaz, G A; Eberly, B; Felix, J; Fields, L; Fine, R; Gago, A M; Gallagher, H; Gran, R; Harris, D A; Higuera, A; Hurtado, K; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; McFarland, K S; McGivern, C L; McGowan, A M; Miller, J; Morfín, J G; Mousseau, J; Nelson, J K; Norrick, A; Osta, J; Palomino, J L; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ramirez, M A; Ransome, R D; Ray, H; Ren, L; Rodrigues, P A; Ruterbories, D; Schellman, H; Schmitz, D W; Sobczyk, J T; Salinas, C J Solano; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wolcott, J; Yepes-Ramirez, H; Zavala, G; Zhang, D; Ziemer, B P

    2015-01-01

    Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \\minerva detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for $\\bar{\

  3. Neutral pion production measurements at SciBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Catala-Perez, J. [IFIC, CSIC/U. Valencia (Spain)

    2011-08-15

    Neutrino-induced neutral pion production is an important measurement for next generation neutrino oscillation experiments. Neutral current (NC) neutral pion production is a direct background for electron neutrino appearance experiments, while charged current (CC) neutral pion production affects experiments looking for muon neutrino disappearance. Located in the Booster Neutrino Beam at Fermilab, SciBooNE is a neutrino scattering experiment designed to accurately measure muon neutrino and anti-neutrino cross sections on carbon near 1 GeV neutrino energy. In this talk I will present recent SciBooNE results on neutral pion production, including the total cross section measurement for both channels relative to the CC inclusive cross section, the separation of the coherent and incoherent contributions to the NC channel, and details on neutral pion production kinematics.

  4. Coherent and neutral pion production results from MINERνA

    Energy Technology Data Exchange (ETDEWEB)

    Palomino, J. L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, 22290-180 (Brazil); Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Higuera, A. [Universidad de Guanajuato, Lascuraín de Retana No. 5, Col. Centro. Guanajuato 36000, Guanajuato. México (Mexico)

    2015-05-15

    MINERνA is a neutrino-nucleus scattering experiment employing multiple nuclear targets. The experiment is studying neutral pion production due to coherent, resonant and deep-inelastic processes, from both charged current and neutral current reactions. Neutral pions are detected through their two photon decay and the resultant electromagnetic showers. We will describe the analysis for the cross sections of inclusive and exclusive processes.

  5. Neutral pion form factor measurement by the NA62 experiment

    Science.gov (United States)

    Zamkovsky, Michal; Ambrosino, F.; Antonelli, A.; Anzivino, G.; Arcidiacono, R.; Baldini, W.; Balev, S.; Batley, J. R.; Behler, M.; Bifani, S.; Biino, C.; Bizzeti, A.; Blazek, T.; Bloch-Devaux, B.; Bocquet, G.; Bolotov, V.; Bucci, F.; Cabibbo, N.; Calvetti, M.; Cartiglia, N.; Ceccucci, A.; Cenci, P.; Cerri, C.; Cheshkov, C.; Chze, J. B.; Clemencic, M.; Collazuol, G.; Costantini, F.; Cotta Ramusino, A.; Coward, D.; Cundy, D.; Dabrowski, A.; DAgostini, G.; Dalpiaz, P.; Damiani, C.; Danielsson, H.; De Beer, M.; Dellacasa, G.; Derr, J.; Dibon, H.; Di Filippo, D.; DiLella, L.; Doble, N.; Duk, V.; Engelfried, J.; Eppard, K.; Falaleev, V.; Fantechi, R.; Fidecaro, M.; Fiorini, L.; Fiorini, M.; Fonseca Martin, T.; Frabetti, P. L.; Fucci, A.; Gallorini, S.; Gatignon, L.; Gersabeck, E.; Gianoli, A.; Giudici, S.; Gonidec, A.; Goudzovski, E.; Goy Lopez, S.; Gushchin, E.; Hallgren, B.; Hita-Hochgesand, M.; Holder, M.; Hristov, P.; Iacopini, E.; Imbergamo, E.; Jeitler, M.; Kalmus, G.; Kekelidze, V.; Kleinknecht, K.; Koval, M.; Kozhuharov, V.; Kubischta, W.; Kurshetsov, V.; Lamanna, G.; Lazzeroni, C.; Lenti, M.; Leonardi, E.; Litov, L.; Lurkin, N.; Madigozhin, D.; Maier, A.; Mannelli, I.; Marchetto, F.; Marel, G.; Markytan, M.; Marouelli, P.; Martini, M.; Masetti, L.; Massarotti, P.; Mazzucato, E.; Michetti, A.; Mikulec, I.; Misheva, M.; Molokanova, N.; Monnier, E.; Moosbrugger, U.; Morales Morales, C.; Moulson, M.; Movchan, S.; Munday, D. J.; Napolitano, M.; Nappi, A.; Neuhofer, G.; Norton, A.; Numao, T.; Obraztsov, V.; Palladino, V.; Patel, M.; Pepe, M.; Peters, A.; Petrucci, F.; Petrucci, M. C.; Peyaud, B.; Piandani, R.; Piccini, M.; Pierazzini, G.; Polenkevich, I.; Popov, I.; Potrebenikov, Y.; Raggi, M.; Renk, B.; Retire, F.; Riedler, P.; Romano, A.; Rubin, P.; Ruggiero, G.; Salamon, A.; Saracino, G.; Savri, M.; Scarpa, M.; Semenov, V.; Sergi, A.; Serra, M.; Shieh, M.; Shkarovskiy, S.; Slater, M. W.; Sozzi, M.; Spadaro, T.; Stoynev, S.; Swallow, E.; Szleper, M.; Valdata-Nappi, M.; Valente, P.; Vallage, B.; Velasco, M.; Veltri, M.; Venditti, S.; Wache, M.; Wahl, H.; Walker, A.; Wanke, R.; Widhalm, L.; Winhart, A.; Winston, R.; Wood, M. D.; Wotton, S. A.; Yushchenko, O.; Zinchenko, A.; Ziolkowski, M.

    2017-07-01

    The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ∼1 million fully reconstructed π 0 Dalitz decay is presented. The limits on dark photon production in π 0 decays from the earlier kaon experiment at CERN, NA48/2, are also reported.

  6. Abelian anomaly and neutral pion production

    Science.gov (United States)

    Roberts, Craig

    2011-04-01

    The process γ* γ -->π0 is fascinating because in order to explain the associated transition form factor within the Standard Model on the full domain of momentum transfer, one must combine, using a single internally-consistent framework, an explanation of the essentially nonperturbative Abelian anomaly with the features of perturbative QCD. The case for attempting this has received a significant boost with the publication of data from the BaBar Collaboration [Phys. Rev. D 80, 052002 (2009)] because, while they agree with earlier experiments on their common domain of squared-momentum-transfer [CELLO - Z. Phys. C 49, 401 (1991); CLEO - Phys. Rev. D 57, 33 (1998)], the BaBar data are unexpectedly far above the prediction of perturbative QCD at larger values of Q2. I will elucidate the sensitivity of the γ* γ -->π0 transition form factor, Gγ* γπ(Q2) , to the pointwise behaviour of the interaction between quarks; and use existing Dyson-Schwinger equation calculations of this and the kindred γ*γ* -->π0 form factor to characterize the Q2-dependence of Gγ* γπ(Q2) . It will become apparent that in fully-self-consistent treatments of pion: static properties; and elastic and transition form factors, the asymptotic limit of the product Q2Gγ* γπ0(Q2) , which is determined a priori by the interaction employed, is not exceeded at any finite value of spacelike momentum transfer: the product is a monotonically-increasing concave function. Studies exist which interpret the BaBar data as an indication that the pion's distribution amplitude, φπ(x) , deviates dramatically from its QCD asymptotic form, indeed, that φπ(x) = constant, or is at least flat and nonvanishing at x = 0 , 1 . I will explain that such a distribution amplitude characterises an essentially-pointlike pion; and show that, when used in a fully-consistent treatment, it produces results for pion elastic and transition form factors that are in striking disagreement with experiment. A bound-state pion

  7. The Positive Pion-Negative Pion-Neutral Pion-Neutral Pion Final State in Two-Photon Physics

    Science.gov (United States)

    Stephens, Ransom Wayne

    The TPC/2gamma detector facility at PEP was used to study the reaction: gammagamma to X to pi^+pi^-pi^0pi ^0 to pi^+pi^-gamma gammagammagamma. This reaction was studied when all four final state photons were detected, thus the whole pi^+pi^ -pi^0pi^0 state was reconstructed; as well as when one of the final state photons escaped detection and so only pi^+pi ^-pi^0gamma was reconstructed. A summary of the current state of meson spectroscopy as well as a review of non-quark model resonance phenomena are presented. The principles of particle radiation detection are described in conjunction with an overview of the TPC/2 gamma detector. The theory of two -photon interactions is recounted along with a presentation of the phenomenological models employed in the analysis. Using the 140 pb^{-1} of untagged data, where the two interacting photons are very nearly real, measurements of continuum production and upper-limits from resonance searches were performed. A new measurement of the topological cross section for the reaction gammagamma to pi ^+pi^-pi^0pi^0 as well as cross sections of its components: rho^+rho^-, rho^+ pi^-pi^0 and uncorrelated pi^+pi^-pi^0 pi^0, are presented. These measurements are consistent with previous measurements and tend to support the hypothesis that the subthreshold enhancement in the reaction: gammagamma to rho ^0rho^0 is a non-quark-model phenomenon. Upper-limits on the production of two states scPRELIMINARILY observed by CELLO are presented. In our 114 pb^{-1} of single-tag data (where one of the photons is quite virtual and the other very nearly real), evidence for a resonance with a corrected mass of about 1525 MeV/c^2 was observed in the pi^+pi ^-pi^0gamma final state. There is good reason to believe that the actual decay channel of this, which I refer to as the R(1525), is the full four -pion channel, pi^+pi^ -pi^0pi^0, where one final state photon was not detected. The upper limits on R(1525) production from untagged pi^+pi ^-pi^0gamma

  8. Hard photon and neutral pion production in cold nuclear matter

    NARCIS (Netherlands)

    Aphecetche, L.; Bacelar, J.C.S; Delagrange, H.; d' Enterria, D.; Hoefman, M.; Huisman, H.; Kalantar-Nayestanaki, N.; Löhner, H.; Martinez, G.; Matulewicz, T.; Messchendorp, J.G.; Mora, M.-J.; Ostendorf, R.W.; Schadmand, S.; Schutz, Y.; Seip, M.; Taranenko, A.; Turrisi, R.; van Goethem, M.J.; Volkerts, M.; Wagner, V.; Wilschut, H.W.E.M.

    2001-01-01

    The production of hard photons and neutral pions in 190 MeV proton induced reactions on C, Ca. Ni, and W targets has been for the first time concurrently studied. Angular distributions and energy spectra up to the kinematical limit are discussed and the production cross-sections are presented. From

  9. Anomalous electrodynamics of neutral pion matter in strong magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Brauner, Tomáš [Department of Mathematics and Natural Sciences, University of Stavanger,N-4036 Stavanger (Norway); Kadam, Saurabh V. [Indian Institute of Science Education and Research (IISER),Pune 411008 (India)

    2017-03-03

    The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions https://arxiv.org/abs/1609.05213. We investigate the interplay between the CSL structure and dynamical electromagnetic fields. Our main result is that in presence of the CSL background, the two physical photon polarizations and the neutral pion mix, giving rise to two gapped excitations and one gapless mode with a nonrelativistic dispersion relation. The nature of this mode depends on the direction of its propagation, interpolating between a circularly polarized electromagnetic wave https://www.doi.org/10.1103/PhysRevD.93.085036 and a neutral pion surface wave, which in turn arises from the spontaneously broken translation invariance. Quite remarkably, there is a neutral-pion-like mode that remains gapped even in the chiral limit, in seeming contradiction to the Goldstone theorem. Finally, we have a first look at the effect of thermal fluctuations of the CSL, showing that even the soft nonrelativistic excitation does not lead to the Landau-Peierls instability. However, it leads to an anomalous contribution to pressure that scales with temperature and magnetic field as T{sup 5/2}(B/f{sub π}){sup 3/2}.

  10. Measurement of neutral current coherent neutral pion production on carbon in a few-GeV neutrino beam

    CERN Document Server

    Kurimoto, Y; Brice, S J; Bugel, L; Catala-Perez, J; Cheng, G; Conrad, J M; Djurcic, Z; Dore, U; Finley, D A; Franke, A J; Giganti, C; Gomez-Cadenas, J J; Guzowski, P; Hanson, A; Hayato, Y; Hiraide, K; Jover-Manas, G; Karagiorgi, G; Katori, T; Kobayashi, Y K; Kobilarcik, T; Kubo, H; Louis, W C; Loverre, P F; Ludovici, L; Mahn, K B M; Mariani, C; Masuike, S; Matsuoka, K; McGary, V T; Metcalf, W; Mills, G B; Mitsuka, G; Miyachi, Y; Mizugashira, S; Moore, C D; Nakajima, Y; Nakaya, T; Napora, R; Nienaber, P; Orme, D; Otani, M; Russell, A D; Sanchez, F; Shaevitz, M H; Shibata, T -A; Sorel, M; Stefanski, R J; Takei, H; Tanaka, H -K; Tanaka, M; Tayloe, R; Taylor, I J; Tesarek, R J; Uchida, Y; Van de Water, R; Walding, J J; Wascko, M O; White, H B; Wilking, M J; Yokoyama, M; Zeller, G P; Zimmerman, E D

    2010-01-01

    The SciBooNE Collaboration reports a measurement of neutral current coherent neutral pion production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive neutral pion production has been improved by detecting recoil protons from resonant neutral pion production. We measure the ratio of the neutral current coherent neutral pion production to total charged current cross sections to be (1.16 +/- 0.24) x 10-2. The ratio of charged current coherent pion to neutral current coherent pion production is calculated to be 0.14+0.30 -0.28, using our published charged current coherent pion measurement.

  11. Precision determination of the lifetime of the neutral pion

    CERN Multimedia

    2002-01-01

    The experiment aims at a determination of the lifetime of the neutral pion with an accuracy of 1\\%, as against at present 5\\% for the best measurement by the indirect, Primakoff method, and 18\\% by a direct measurement. \\\\\\\\2 gold foils with different separations are traversed by the extracted proton beam to the High Intensity Area. Positive particles of 160 GeV/c momentum from this target are transported by the H6 beam to the North Area. The electron component is separated from heavier particles by synchrotron losses in the bending magnets, and is further identified by a lead glass Cerenkov counter, in coincidence with scintillation counters (Fig. 1).\\\\\\\\ The electron flux from the double foil target depends on the distance between the foils, since for small separations the neutral pions will have to decay before electrons can be materialised by the decay $\\gamma$ rays.\\\\\\\\ The average momentum of neutral pions from a 400 GeV pN reaction, giving a 160 GeV/c electron, is about 250 GeV/c, and the corresponding...

  12. Subthreshold Production of Neutral Pions in Heavy Ion Collisions

    CERN Multimedia

    2002-01-01

    The pion production below the threshold at 290 MeV/u (corresponding to the minimum beam velocity at which pions can be produced in nucleon-nucleon collisions) is sensitive to coherent effects in the momentum distribution of the nucleons in the internuclear collision region. Such collective or coherent effects would manifest themselves in an enhancement of the observed cross section with respect to a prediction on the basis of model momentum distributions, e.g. from the Fermi gas model. \\\\ \\\\ With neutral pions such experiments can be extended to rather low energies and rather small cross sections (in the sub-@mb range) due to the fact that the @p|0's leave the composite nuclear system undisturbed by the Coulomb forces and that their decay $\\gamma$ rays can be detected with high efficiency also at very low pion momentum. In our experiments using |1|2C~ions of 60, 74 and 84~MeV/u and |1|80 of 84~MeV/u we were able to clearly sep from background from different sources. The large efficiency of the annular lead gl...

  13. Evidence for neutral-current diffractive neutral pion production from hydrogen in neutrino interactions on hydrocarbon

    CERN Document Server

    Wolcott, J; Altinok, O; Bercellie, A; Betancourt, M; Bodek, A; Bravar, A; Budd, H; Cai, T; Carneiro, M F; Chvojka, J; Devan, J; Dytman, S A; Diaz, G A; Eberly, B; Endress, E; Felix, J; Fields, L; Galindo, R; Gallagher, H; Golan, T; Gran, R; Harris, D A; Higuera, A; Hurtado, K; Kiveni, M; Kleykamp, J; Kordosky, M; Le, T; Maher, E; Manly, S; Mann, W A; Marshall, C M; Caicedo, D A Martinez; McFarland, K S; McGivern, C L; McGowan, A M; Messerly, B; Miller, J; Mislivec, A; Morfin, J G; Mousseau, J; Naples, D; Nelson, J K; Norrick, A; Nuruzzaman,; Paolone, V; Park, J; Patrick, C E; Perdue, G N; Rakotondravohitra, L; Ramirez, M A; Ray, H; Ren, L; Rimal, D; Rodrigues, P A; Ruterbories, D; Schellman, H; Schmitz, D W; Salinas, C J Solano; Sanchez, S F; Tagg, N; Tice, B G; Valencia, E; Walton, T; Wospakrik, M; Zhang, D

    2016-01-01

    The MINERvA experiment observes an excess of events containing electromagnetic showers relative to the expectation from Monte Carlo simulations in neutral-current neutrino interactions with mean beam energy of 4.5 GeV on a hydrocarbon target. The excess is characterized and found to be consistent with neutral-current neutral pion production with a broad energy distribution peaking at 7 GeV and a total cross section of 0.26 +- 0.02 (stat) +- 0.08 (sys) x 10^{-39} cm^{2}. The angular distribution, electromagnetic shower energy, and spatial distribution of the energy depositions of the excess are consistent with expectations from neutrino neutral-current diffractive neutral pion production from hydrogen in the hydrocarbon target. These data comprise the first direct experimental observation and constraint for a reaction that poses an important background process in neutrino oscillation experiments searching for muon neutrino to electron neutrino oscillations.

  14. Inclusive Production of Neutral Pions in Hadronic Z Decays

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Bazarko, A O; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rizzo, G; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Martin, E B; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Leroy, O; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1997-01-01

    A measurement of the inclusive production of pi0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at LEP at a centre-of-mass energy of sqrt(s) = 91.2 GeV. Neutral pions are reconstructed using photons from conversion pairs and photons measured in the electromagnetic calorimeter. The inclusive pi0 momentum spectrum is measured in the range from 0.025 < x(p) = p/p(beam) < 1 to be 4.80 +/- 0.07(stat) +/- 0.31(sys). The differential inclusive pi0 cross section has also been measured as a function of transverse momentum with respect to the event plane (p_T^in and p_T^out_T).

  15. Analysis of Neutral Pion Helicity Asymmetry with the STAR Detector

    Science.gov (United States)

    Hauck, Alec; Strand, Noah; STAR Collaboration

    2017-09-01

    The gluon contribution to the proton spin is poorly constrained compared to the quark contribution. To further constrain the gluon contribution, the STAR collaboration at RHIC analyzes the asymmetry in neutral pion (π0) production as a function of spin alignment in longitudinally polarized proton beam collisions. These π0s mostly decay into photon pairs, some of which are identified in the Endcap Electromagnetic Calorimeter (EEMC) within the STAR detector. The EEMC has a pseudorapidity range of 1 < η < 2 with full azimuthal coverage. The EEMC's Shower Max Detector (SMD) determines the positions of photon showers. A first step in identifying photons is reconstructing clusters of energy in each layer of the SMD. Knowing the position and energy of these photons allows us to reconstruct the π0s they decayed from. From these reconstructed π0s, a corrected count is determined by fitting signal and background templates from Monte Carlo simulation to the π0 candidate invariant mass distributions. We will describe the state of our analysis on the √{ s} = 510 GeV dataset from 2012 (integrated luminosity 82 pb-1) including cluster identification, Monte Carlo simulation, and data. We will also give a first glimpse of the 2013 dataset (300 pb-1).

  16. Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z Decays

    CERN Document Server

    Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Baarmand, M.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; Dai, T.S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duinker, P.; Echenard, B.; Eline, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Ewers, A.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, H.J.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luckey, David; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wu, S.X.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

    2002-01-01

    Bose-Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic $\\mathrm{Z}$ decays collected with the L3 detector at LEP. The analysis is performed in the four-momentum difference range $300 \\mathrm{\\ Me\\kern -0.1em V} < Q < 2 \\mathrm{\\ Ge\\kern -0.1em V}$. The radius of the neutral pion source is found to be smaller than that of charged pions. This result is in qualitative agreement with the string fragmentation model. \\end{document}

  17. A Precision Measurement of the Neutral Pion Lifetime via the Primakoff Effect

    Energy Technology Data Exchange (ETDEWEB)

    Clinton, Eric [Univ. of Massachusetts, Amherst, MA (United States)

    2007-09-01

    The neutral pion radiative width has been measured to 8.411 eV ± 1.8% + 1.13% - 1.70% (lifetime = 7.826 ± 0.14 + 0.088 - 0.133 x 10-17 s) utilizing the Primakoff effect and roughly 4.9 to 5.5 GeV photons at the Thomas Jefferson National Accelerator Facility in Newport News, VA. The Hall B Photon Tagger, the Hall B Pair Spectrometer, a state of the art Hybrid Calorimter enabled precision incident photon energy measurement, photon flux measurement, and neutral pion identification, respectively. With these and other hardware and software tools, elastic neutral pion yields were extracted from the data. A well developed and understood simulation calculated geometric and software cut efficiency curves. The simulation also provided photo-pion production response functions to fit the experimental cross sections and extract the Primakoff cross section and thus the neutral pion radiative width and lifetime. Future work includes improving understanding of the nuclear incoherent process and any other background sources of elastic neutral pions in this data.

  18. Search for a neutral particle of mass 33.9 MeV in pion decay

    Energy Technology Data Exchange (ETDEWEB)

    Daum, M.; Frosch, R.; Hajdas, W. [PSI Paul Scherrer Inst., Villingen-PSI (Switzerland)] [and others

    1997-12-31

    The muon momentum distribution in charged pion decay in flight in order to search for a small branching fraction {eta} of pion decays {pi}{sup +} {yields} {mu}{sup +} + X, in which a heavy neutral particle X with a mass of 33.9 MeV would be emitted has been measured. The upper limit of {eta} at a confidence level of 95 % is found to be 2.6 x 1{sup -8}. (orig.)

  19. A measurement of coherent neutral pion production in neutrino neutral current interactions in the NOMAD experiment

    Science.gov (United States)

    Kullenberg, C. T.; Mishra, S. R.; Seaton, M. B.; Kim, J. J.; Tian, X. C.; Scott, A. M.; Kirsanov, M.; Petti, R.; Alekhin, S.; Astier, P.; Autiero, D.; Baldisseri, A.; Baldo-Ceolin, M.; Banner, M.; Bassompierre, G.; Benslama, K.; Besson, N.; Bird, I.; Blumenfeld, B.; Bobisut, F.; Bouchez, J.; Boyd, S.; Bueno, A.; Bunyatov, S.; Camilleri, L.; Cardini, A.; Cattaneo, P. W.; Cavasinni, V.; Cervera-Villanueva, A.; Challis, R.; Chukanov, A.; Collazuol, G.; Conforto, G.; Conta, C.; Contalbrigo, M.; Cousins, R.; Degaudenzi, H.; De Santo, A.; Del Prete, T.; Di Lella, L.; do Couto e Silva, E.; Dumarchez, J.; Ellis, M.; Feldman, G. J.; Ferrari, R.; Ferrère, D.; Flaminio, V.; Fraternali, M.; Gaillard, J.-M.; Gangler, E.; Geiser, A.; Geppert, D.; Gibin, D.; Gninenko, S.; Godley, A.; Gomez-Cadenas, J.-J.; Gosset, J.; Gößling, C.; Gouanère, M.; Grant, A.; Graziani, G.; Guglielmi, A.; Hagner, C.; Hernando, J.; Hurst, P.; Hyett, N.; Iacopini, E.; Joseph, C.; Juget, F.; Kent, N.; Klimov, O.; Kokkonen, J.; Kovzelev, A.; Krasnoperov, A.; Kulagin, S.; Lacaprara, S.; Lachaud, C.; Lakić, B.; Lanza, A.; La Rotonda, L.; Laveder, M.; Letessier-Selvon, A.; Levy, J.-M.; Ling, J.; Linssen, L.; Ljubičić, A.; Long, J.; Lupi, A.; Lyubushkin, V.; Marchionni, A.; Martelli, F.; Méchain, X.; Mendiburu, J.-P.; Meyer, J.-P.; Mezzetto, M.; Moorhead, G. F.; Naumov, D.; Nédélec, P.; Nefedov, Yu.; Nguyen-Mau, C.; Orestano, D.; Pastore, F.; Peak, L. S.; Pennacchio, E.; Pessard, H.; Placci, A.; Polesello, G.; Pollmann, D.; Polyarush, A.; Poulsen, C.; Popov, B.; Rebuffi, L.; Rico, J.; Riemann, P.; Roda, C.; Rubbia, A.; Salvatore, F.; Samoylov, O.; Schahmaneche, K.; Schmidt, B.; Schmidt, T.; Sconza, A.; Sevior, M.; Sillou, D.; Soler, F. J. P.; Sozzi, G.; Steele, D.; Stiegler, U.; Stipčević, M.; Stolarczyk, Th.; Tareb-Reyes, M.; Taylor, G. N.; Tereshchenko, V.; Toropin, A.; Touchard, A.-M.; Tovey, S. N.; Tran, M.-T.; Tsesmelis, E.; Ulrichs, J.; Vacavant, L.; Valdata-Nappi, M.; Valuev, V.; Vannucci, F.; Varvell, K. E.; Veltri, M.; Vercesi, V.; Vidal-Sitjes, G.; Vieira, J.-M.; Vinogradova, T.; Weber, F. V.; Weisse, T.; Wilson, F. F.; Winton, L. J.; Wu, Q.; Yabsley, B. D.; Zaccone, H.; Zuber, K.; Zuccon, P.

    2009-11-01

    We present a study of exclusive neutral pion production in neutrino-nucleus Neutral Current interactions using data from the NOMAD experiment at the CERN SPS. The data correspond to 1.44 ×106 muon-neutrino Charged Current interactions in the energy range 2.5 ⩽Eν ⩽ 300 GeV. Neutrino events with only one visible π0 in the final state are expected to result from two Neutral Current processes: coherent π0 production, ν + A → ν + A +π0 and single π0 production in neutrino-nucleon scattering. The signature of coherent π0 production is an emergent π0 almost collinear with the incident neutrino while π0's produced in neutrino-nucleon deep inelastic scattering have larger transverse momenta. In this analysis all relevant backgrounds to the coherent π0 production signal are measured using data themselves. Having determined the backgrounds, and using the Rein-Sehgal model for the coherent π0 production to compute the detection efficiency, we obtain 4630 ± 522 (stat) ± 426 (syst) corrected coherent-π0 events with Eπ0 ⩾ 0.5 GeV. We measure σ (νA → νAπ0) = [ 72.6 ± 8.1 (stat) ± 6.9 (syst) ] ×10-40 cm2 /nucleus. This is the most precise measurement of the coherent π0 production to date.

  20. High transverse momentum inclusive neutral pion production in d+Au collisions at RHIC

    NARCIS (Netherlands)

    Grebenyuk, O.|info:eu-repo/dai/nl/304848883; Mischke, A.|info:eu-repo/dai/nl/325781435; Stolpovsky, A.

    2006-01-01

    Preliminary results are presented on high pT inclusive neutral pion production in d+Au collisions at sNN = 200 GeV in the pseudo-rapidity range 0 <η <1. Photons from the decay π0 → γγ are detected in the Barrel Electromagnetic Calorimeter of the STAR experiment at RHIC. The analysis procedure is

  1. Search for a neutral particle of mass 33.9 MeV in pion decay

    Energy Technology Data Exchange (ETDEWEB)

    Daum, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    We have measured the muon momentum distribution in charged pion decay in flight in order to search for a small branching fraction {eta} of pion decays {pi}{sup +}{yields}{mu}{sup +} 1 X, in which a heavy neutral particle X with a mass of 33.9 MeV would be emitted. Such a particle was postulated by the KARMEN collaboration as a possible explanation for an anomaly in their time-of-flight spectrum. In a first experiment we found an upper limit of {eta}{<=}2.6.10{sup -8} at a confidence level of 95%. (author) 4 figs., 9 refs.

  2. Search for a 33.9 MeV/c2 Neutral Particle in Pion Decay

    Science.gov (United States)

    Formaggio, J. A.; Zimmerman, E. D.; Adams, T.; Alton, A.; Avvakumov, S.; de Barbaro, L.; de Barbaro, P.; Bernstein, R. H.; Bodek, A.; Bolton, T.; Brau, J.; Buchholz, D.; Budd, H.; Bugel, L.; Case, S.; Conrad, J. M.; Drucker, R. B.; Fleming, B. T.; Frey, R.; Goldman, J.; Goncharov, M.; Harris, D. A.; Johnson, R. A.; Kim, J. H.; Koutsoliotas, S.; Lamm, M. J.; Marsh, W.; Mason, D.; McFarland, K. S.; McNulty, C.; Naples, D.; Nienaber, P.; Romosan, A.; Sakumoto, W. K.; Schellman, H. M.; Shaevitz, M. H.; Spentzouris, P.; Stern, E. G.; Vakili, M.; Vaitaitis, A.; Wu, V.; Yang, U. K.; Yu, J.; Zeller, G. P.

    2000-05-01

    The E815 (NuTeV) neutrino experiment has performed a search for a 33.9 MeV/c2 weakly interacting neutral particle produced in pion decay. Such a particle may be responsible for an anomaly in the timing distribution of neutrino interactions in the KARMEN experiment. E815 has searched for this particle's decays in an instrumented decay region; no evidence for this particle was found. The search is sensitive to pion branching ratios as low as 10-13.

  3. Measurement of Neutral Current Neutral Pion Production on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kurimoto, Yoshinori [Kyoto Univ. (Japan)

    2010-01-01

    Understanding of the π0 production via neutrino-nucleus neutral current interaction in the neutrino energy region of a few GeV is essential for the neutrino oscillation experiments. In this thesis, we present a study of neutral current π0 production from muon neutrinos scattering on a polystyrene (C8H8) target in the SciBooNE experiment. All neutrino beam data corresponding to 0.99 × 1020 protons on target have been analyzed. We have measured the cross section ratio of the neutral current π0 production to the total charge current interaction and the π0 kinematic distribution such as momentum and direction. We obtain [7.7 ± 0.5(stat.) ± 0.5(sys.)] × 10-2 as the ratio of the neutral current neutral pion production to total charged current cross section; the mean energy of neutrinos producing detected neutral pions is 1.1 GeV. The result agrees with the Rein- Sehgal model, which is generally used for the Monte Carlo simulation by many neutrino oscillation experiments. We achieve less than 10 % uncertainty which is required for the next generation search for νµ → νe oscillation. The spectrum shape of the π0 momentum and the distribution of the π0 emitted angle agree with the prediction, which means that not only the Rein-Sehgal model but also the intra-nuclear interaction models describe our data well. We also measure the ratio of the neutral current coherent pion production to total charged current cross section to be (1.17 ± 0.23 ) × 10-2 based on the Rein and Sehgal model. The result gives the evidence for non-zero coherent pion production via neutral current interaction at the mean neutrino energy of 1.0 GeV.

  4. Charged-Current Neutral Pion production at SciBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Catala-Perez, J.; /Valencia U., IFIC

    2009-10-01

    SciBooNE, located in the Booster Neutrino Beam at Fermilab, collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon below 1 GeV neutrino energy. SciBooNE is studying charged current interactions. Among them, neutral pion production interactions will be the focus of this poster. The experimental signature of neutrino-induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the {pi}{sup 0} decay photons, with an additional muon in the final state for CC processes. In this poster, I will present how we reconstruct and select charged-current muon neutrino interactions producing {pi}{sup 0}'s in SciBooNE.

  5. Nuclear Targets for a Precision Measurement of the Neutral Pion Radiative Width

    Energy Technology Data Exchange (ETDEWEB)

    Martel, Philippe; Clinton, Eric; McWilliams, R.; Lawrence, Dave; Miskimen, Rory; Ahmidouch, Abdellah; Ambrozewicz, Pawel; Asaturyan, Arshak; Baker, O.; Benton, LaRay; Bernstein, Aron; Cole, Philip; Collins, Patrick; Dale, Daniel; Danagoulian, Samuel; Davidenko, G.; Demirchyan, Raphael; Deur, Alexandre; DOLGOLENKO, A.; Dzyubenko, Georgiy; Evdokimov, Anatoly; Feng, JIng; Gabrielyan, Marianna; Gan, Liping; Gasparian, Ashot; Glamazdin, Oleksandr; Goryachev, Vladimir; Gyurjyan, Vardan; Hardy, K.; Ito, Mark; Khandaker, Mahbubul; Kingsberry, Paul; Kolarkar, Ameya; Konchatnyi, Mykhailo; Korchin, O.; Korsch, Wolfgang; Kowalski, Stanley; Kubantsev, Mikhail; Kubarovsky, Valery; LARIN, Ilya; MATVEEV, V.; McNulty, Dustin; Milbrath, Brian; Minehart, Ralph; Mochalov, Vasiliy; Mtingwa, Sekazi; Nakagawa, Itaru; Overby, Steven; Pasyuk, Evgueni; Payen, Marvin; Pedroni, Ronald; Prok, Yelena; Ritchie, Barry; Salgado, Carlos; Sitnikov, Anatoly; Sober, Daniel; Stephens, W.; Teymurazyan, Aram; Underwood, Jarreas; VASILIEV, A.; VEREBRYUSOV, V.; Vishnyakov, Vladimir; Wood, Michael

    2009-12-01

    A technique is presented for precision measurements of the area densities, density * T, of approximately 5% radiation length carbon and 208Pb targets used in an experiment at Jefferson Laboratory to measure the neutral pion radiative width. The precision obtained in the area density for the carbon target is +/- 0.050%, and that obtained for the lead target through an x-ray attenuation technique is +/- 0.43%.

  6. Azimuthal asymmetry in electro-production of neutral pions in SIDIS

    CERN Document Server

    Efremov, A V; Schweitzer, P

    2001-01-01

    Recently HERMES has observed an azimuthal asymmetry in electro-production of neutral pions in semi-inclusive deep-inelastic scattering of unpolarized positrons off longitudinally polarized protons. This asymmetry (like those observed in the production of charged pions) is well reproduced theoretically by using the non-perturbative calculation of the proton transversity distribution in the effective chiral quark-soliton model combined with experimental DELPHI-data on the new T-odd Collins fragmentation function. There are no free, adjustable parameters in the analysis. Using the $z$-dependence of the HERMES azimuthal asymmetry and the calculated transversity distributions the z-dependence of the Collins fragmentation function is obtained. The value obtained from HERMES data is consistent with the DELPHI result, even though these results refer to different scales.

  7. Near Threshold Neutral Pion Electroproduction at High Momentum Transfers and Generalized Form Factors

    CERN Document Server

    Khetarpal, P; Aznauryan, I G; Kubarovsky, V; Adhikari, K P; Adikaram, D; Aghasyan, M; Amaryan, M J; Anderson, M D; Pereira, S Anefalos; Anghinolfi, M; Avakian, H; Baghdasaryan, H; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Bono, J; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Charles, G; Cole, P L; Contalbrigo, M; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Doughty, D; Dugger, M; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Eugenio, P; Fedotov, G; Fegan, S; Fersch, R; Fleming, J A; Fradi, A; Gabrielyan, M Y; Garçon, M; Gevorgyan, N; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hicks, K; Ho, D; Holtrop, M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Klein, F J; Koirala, S; Kubarovsky, A; Kuleshov, S V; Kvaltine, N D; Lewis, S; Livingston, K; Lu, H Y; MacGregor, I J D; Mao, Y; Martinez, D; Mayer, M; McKinnon, B; Meyer, C A; Mineeva, T; Mirazita, M; Mokeev, V; Montgomery, R A; Moutarde, H; Munevar, E; Camacho, C Munoz; Nadel-Turonski, P; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Park, K; Park, S; Pasyuk, E; Phelps, E; Phillips, J J; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Protopopescu, D; Puckett, A J R; Raue, B A; Ricco, G; Rimal, D; Ripani, M; Rosner, G; Rossi, P; Sabatié, F; Saini, M S; Salgado, C; Saylor, N A; Schott, D; Schumacher, R A; Seder, E; Seraydaryan, H; Sharabian, Y G; Smith, G D; Sober, D I; Sokhan, D; Stepanyan, S S; Stepanyan, S; Strakovsky, I I; Strauch, S; Taiuti, M; Tang, W; Taylor, C E; Tkachenko, S; Ungaro, M; Vernarsky, B; Voskanyan, H; Voutier, E; Walford, N K; Weinstein, L B; Weygand, D P; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2012-01-01

    We report the measurement of near threshold neutral pion electroproduction cross sections and the extraction of the associated structure functions on the proton in the kinematic range $Q^2$ from 2 to 4.5 GeV$^2$ and $W$ from 1.08 to 1.16 GeV. These measurements allow us to access the dominant pion-nucleon s-wave multipoles $E_{0+}$ and $S_{0+}$ in the near-threshold region. In the light-cone sum-rule framework (LCSR), these multipoles are related to the generalized form factors $G_1^{\\pi^0 p}(Q^2)$ and $G_2^{\\pi^0 p}(Q^2)$. The data are compared to these generalized form factors and the results for $G_1^{\\pi^0 p}(Q^2)$ are found to be in good agreement with the LCSR predictions, but the level of agreement with $G_2^{\\pi^0 p}(Q^2)$ is poor.

  8. Transverse single-spin asymmetries for direct photon and neutral pion production in midrapidity at PHENIX

    Science.gov (United States)

    Lewis, Nicole; Phenix Collaboration

    2017-09-01

    Large transverse single spin asymmetries for hadron production in proton-proton collisions were some of the first indicators of significant nonperturbative spin-momentum correlations in the proton. They have been found to persist up to collision energies of 510 GeV, yet their origin remains poorly understood. Measurements of different final-state particles in a wide variety of collision systems over a range of kinematics can help to identify and separate contributions from the proton versus hadronization, and from different parton flavors. Depending on the rapidity pion production can provide access to both initial- and final-state effects for a mix of parton flavors, while direct photons depend only on initial-state effects and are particularly sensitive to gluon dynamics in RHIC kinematics. The status of transverse single spin measurements for neutral pions and direct photons performed for p+p, p+Al, and p+Au collisions at PHENIX will be presented.

  9. Analysis of the semileptonic neutral D meson decays to neutral antikaon pion muon neutrino

    Science.gov (United States)

    Segoni, Ilaria Maria Lucia

    This thesis describes the analysis of the semileptonic decay D0→K0p- m+n using FOCUS data. FOCUS is a fixed target experiment at Fermilab that studies the physics of the charm quark. Particles containing charm are produced by photon-gluon fusion from the collision of a photon beam on a BeO target. The experiment is characterized by excellent vertex resolution and particle identification. The spectrometer consists of three systems for track reconstruction (two silicon systems and one multiwire proportional chamber system) and two magnets of opposite polarity. The polarity of the magnet is such that the events of e+e- pairs produced in the target (which constitutes the main background) travel through a central opening in the detectors without interactions. Particle momentum is measured from the deflection angle in the magnets. Three multi-cell Cerenkov counters are used for charged particle identification (for e, p , K, and p). Two different tracking systems located after several interaction lengths of shielding material are used for muon identification. The energy of neutral pions and electrons is measured in two electromagnetic calorimeters, while an hadron calorimeter is used for measuring the neutron energy. During the last four years the FOCUS collaboration provided results on several charm topics: CP violation, D0-- D0 mixing, rare and forbidden decays, precision measurements of semileptonic decays, baryon and meson lifetimes, fully hadronic baryon and meson branching ratios, charm spectroscopy, Dalitz analyses of resonant structures, charm anti-charm production, QCD studies involving double charm particles, and pentaquarks. In this thesis we present the first measurement of the form factor ratios rv and r2 for the decay D0→K0p- m+n . We use a model where the K0p- system is described by a spin 1 component, the K*(892) -, interfering with a small S-wave component of constant amplitude and phase (Aeidelta). This model was introduced by FOCUS for the analysis

  10. Measurement Of Inclusive Forward Neutral Pion Production In 200 Gev Polarized Proton-proton Collisions At Rhic

    CERN Document Server

    Wang, Y

    2004-01-01

    Measurement of inclusive forward π0 production in the first polarized p-p collision at s = 200 GeV was achieved using a prototype Forward (neutral) Pion Detector. The invariant differential cross section was consistent with next-to-leading order perturbative QCD calculation. Large positive analyzing power was found for large Feynman-x (xF > 0.3). In addition, a new analysis program was developed for the upgraded Forward Pion Detector (FPD).

  11. A precision measurement of direct CP violation in the decay of neutral kaons into two pions

    CERN Document Server

    Batley, J Richard; Gershon, T J; Kalmus, George Ernest; Lazzeroni, C; Munday, D J; Olaiya, E; Patel, M; Parker, M A; White, T O; Wotton, S A; Arcidiacono, R; Barr, Giles David; Bocquet, G; Ceccucci, Augusto; Çuhadar-Dönszelmann, T; Cundy, Donald C; Doble, Niels T; Falaleev, V P; Gatignon, L; Gonidec, A; Gorini, B; Grafström, P; Kubischta, Werner; Mikulec, I; Norton, Alan Robert; Palestini, S; Panzer-Steindel, B; Schinzel, D; Wahl, H; Cheshkov, C; Khristov, P Z; Kekelidze, V D; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Zinchenko, A I; Rubin, P; Sacco, R; Walker, A; Bettoni, D; Calabrese, R; Dalpiaz, Pietro; Duclos, J; Frabetti, P L; Gianoli, A; Martini, M; Masetti, L; Petrucci, F; Savrié, M; Scarpa, M; Bizzeti, A; Calvetti, M; Collazuol, G; Iacopini, E; Lenti, M; Martelli, F; Ruggiero, G; Veltri, M; Coward, D; Eppard, M; Hirstius, A; Holtz, K; Kleinknecht, K; Koch, U; Köpke, L; Lopes da Silva, P; Marouelli, P; Mestvirishvili, I; Morales, C; Pellmann, I A; Peters, A; Renk, B; Schmidt, S A; Schönharting, V; Wanke, R; Winhart, A; Chollet, J C; Fayard, Louis; Graziani, G; Iconomidou-Fayard, L; Unal, G; Wingerter-Seez, I; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Lamanna, G; Lubrano, P; Mestvirishvili, A; Nappi, A; Pepé, M; Piccini, M; Valdata-Nappi, M; Casali, R; Cerri, C; Cirilli, M; Costantini, F; Fantechi, R; Fiorini, Luca; Giudici, Sergio; Mannelli, I; Pierazzini, G M; Sozzi, M; Chèze, J B; De Beer, M; Debu, P; Derue, F; Formica, A; Gouge, G; Marel, Gérard; Mazzucato, E; Peyaud, B; Turlay, René; Vallage, B; Holder, M; Maier, A; Ziolkowski, M; Biino, C; Cartiglia, N; Clemencic, M; Marchetto, F; Menichetti, E; Pastrone, N; Nassalski, J P; Rondio, Ewa; Wislicki, W; Wronka, S; Dibon, Heinz; Jeitler, Manfred; Markytan, Manfred; Neuhofer, Günther; Pernicka, Manfred; Taurok, Anton; Widhalm, L

    2002-01-01

    The direct CP violation parameter Re($\\epsilon'/\\epsilon)$ has been measured from the decay rates of neutral kaons into two pions using the NA48 detector at the CERN SPS. The 2001 running period was devoted to collecting additional data under varied conditions compared to earlier years (1997-99). The new data yield the result: Re($\\epsilon'/\\epsilon)$=$(13.7\\pm3.1)\\ times10^{-4}$. Combining this result with that published from the 1997 98 and 99 data, an overall value of Re($\\epsilon'/\\epsilon)$=$(14.7\\pm2.2)\\times10^{-4 }$ is obtained from the NA48 experiment.

  12. Transverse momentum distributions of neutral pions from nuclear collisions at 200 AGeV

    CERN Document Server

    Albrecht, R; Awes, T C; Barlag, C; Bloomer, M A; Blume, C; Bock, D; Bock, R; Bohne, E M; Bucher, D; Claussen, A; Clewing, G; Eklund, A; Fokin, S; Franz, A; Garpman, S; Geurts, F; Glasow, R; Gustafsson, H °A; Gutbrod 1, H H; Hölker, G; Idh, J; Ippolitov, M; Jacobs, P; Kamermans, R; Kampert 4, K -H; Karadjev, K; Kolb, B W; Lebedev, A; L¨ohner, H; Lund, I; Manko, V; Nikolaev, S; Obenshain, F E; Oskarsson, A; Otterlund, I; Peitzmann, T; Plasil, F; Poskanzer, A M; Purschke, M; Ritter, H G; Saini, S; Santo, R; Schmidt, H R; S¨oderstrom, K; Sørensen, S P; Stankus, P; Steffens, K; Steinhaeuser, P; Stenlund, E; St¨uken, D; Twenh¨ofel, C; Vinogradov, A; Young, G R

    1998-01-01

    New results on transverse mass spectra of neutral pions measured at central rapidity are presented for impact parameter selected 200 AGeV S + S and S + Au collisions. The spectra from all systems show a clear power-law like shape with similar curvature. Collisions of S + Au exhibit a larger mean transverse momentum than pp increasing with centrality. Predictions of string models and by hydrodynamic approaches including collective expansion and decays of short lived resonances are compared to the data and the implications are discussed.

  13. Experimental study of the atmospheric neutrino backgrounds for proton decay to positron and neutral pion searches in water Cherenkov detectors

    CERN Document Server

    Mine, S; Andringa, S; Aoki, S; Argyriades, J; Asakura, K; Ashie, R; Berghaus, F; Berns, H; Bhang, H; Blondel, A; Borghi, S; Bouchez, J; Burguet-Castell, J; Casper, D; Catala, J; Cavata, C; Cervera-Villanueva, Anselmo; Chen, S M; Cho, K O; Choi, J H; Dore, U; Espinal, X; Fechner, M; Fernández, E; Fujii, Y; Fukuda, Y; Gomez-Cadenas, J; Gran, R; Hara, T; Hasegawa, M; Hasegawa, T; Hayato, Y; Helmer, R L; Hiraide, K; Hosaka, J; Ichikawa, A K; Iinuma, M; Ikeda, A; Ishida, T; Ishihara, K; Ishii, T; Ishitsuka, M; Itow, Y; Iwashita, T; Jang, H I; Jeon, E J; Jeong, I S; Joo, K K; Jover, G; Jung, C K; Kajita, T; Kameda, J; Kaneyuki, K; Kato, I; Kearns, E; Kim, C O; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kim, J Y; Kim, S B; Kitching, P; Kobayashi, K; Kobayashi, T; Konaka, A; Koshio, Y; Kropp, W; Kudenko, Yu; Kuno, Y; Kurimoto, Y; Kutter, T; Learned, J; Likhoded, S; Lim, I T; Loverre, P F; Ludovici, L; Maesaka, H; Mallet, J; Mariani, C; Matsuno, S; Matveev, V; McConnel, K; McGrew, C; Mikheyev, S; Minamino, A; Mineev, O; Mitsuda, C; Miura, M; Moriguchi, Y; Moriyama, S; Nakadaira, T; Nakahata, M; Nakamura, K; Nakano, I; Nakaya, T; Nakayama, S; Namba, T; Nambu, R; Nawang, S; Nishikawa, K; Nitta, K; Nova, F; Novella, P; Obayashi, Y; Okada, A; Okumura, K; Oser, S M; Oyama, Y; Pac, M Y; Pierre, F; Rodríguez, A; Saji, C; Sakuda, M; Sánchez, F; Scholberg, K; Schroeter, R; Sekiguchi, M; Shiozawa, M; Shiraishi, K; Sitjes, G; Smy, M; Sobel, H; Sorel, M; Stone, J; Sulak, L; Suzuki, A; Suzuki, Y; Tada, M; Takahashi, T; Takenaga, Y; Takeuchi, Y; Taki, K; Takubo, Y; Tamura, N; Tanaka, M; Terri, R; T'Jampens, S; Tornero-Lopez, A; Totsuka, Y; Vagins, M; Whitehead, L; Walter, C W; Wang, W; Wilkes, R J; Yamada, S; Yamada, Y; Yamamoto, S; Yanagisawa, C; Yershov, N; Yokoyama, H; Yokoyama, M; Yoo, J; Yoshida, M; Zalipska, J

    2008-01-01

    The atmospheric neutrino background for proton decay to positron and neutral pion in ring imaging water Cherenkov detectors is studied with an artificial accelerator neutrino beam for the first time. In total, about 314,000 neutrino events corresponding to about 10 megaton-years of atmospheric neutrino interactions were collected by a 1,000 ton water Cherenkov detector (KT). The KT charged-current single neutral pion production data are well reproduced by simulation programs of neutrino and secondary hadronic interactions used in the Super-Kamiokande (SK) proton decay search. The obtained proton to positron and neutral pion background rate by the KT data for SK from the atmospheric neutrinos whose energies are below 3 GeV is about two per megaton-year. This result is also relevant to possible future, megaton-scale water Cherenkov detectors.

  14. First Search for Exotic Z Boson Decays into Photons and Neutral Pions in Hadron Collisions

    Science.gov (United States)

    Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; D'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Galloni, C.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lucà, A.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Marchese, L.; Margaroli, F.; Marino, P.; Martínez, M.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Song, H.; Sorin, V.; St. Denis, R.; Stancari, M.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vázquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizán, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S. M.; Waters, D.; Wester, W. C., III; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Zanetti, A. M.; Zeng, Y.; Zhou, C.; Zucchelli, S.; CDF Collaboration

    2014-03-01

    A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb-1 of integrated luminosity from proton-antiproton collisions at √s =1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01×10-5 for Z→π0γ, 1.46×10-5 for Z→γγ, and 1.52×10-5 for Z→π0π0. The Z→π0γ and Z→γγ limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z→π0π0 branching ratio limit is the first experimental result on this decay.

  15. First Search for Exotic Z Boson Decays into Photons and Neutral Pions in Hadron Collisions

    CERN Document Server

    Aaltonen, Timo Antero; Amidei, Dante E; Anastassov, Anton Iankov; Annovi, Alberto; Antos, Jaroslav; Apollinari, Giorgio; Appel, Jeffrey A; Arisawa, Tetsuo; Artikov, Akram Muzafarovich; Asaadi, Jonathan A; Ashmanskas, William Joseph; Auerbach, Benjamin; Aurisano, Adam J; Azfar, Farrukh A; Badgett, William Farris; Bae, Taegil; Barbaro-Galtieri, Angela; Barnes, Virgil E; Barnett, Bruce Arnold; Barria, Patrizia; Bartos, Pavol; Bauce, Matteo; Bedeschi, Franco; Behari, Satyajit; Bellettini, Giorgio; Bellinger, James Nugent; Benjamin, Douglas P; Beretvas, Andrew F; Bhatti, Anwar Ahmad; Bland, Karen Renee; Blumenfeld, Barry J; Bocci, Andrea; Bodek, Arie; Bortoletto, Daniela; Boudreau, Joseph Francis; Boveia, Antonio; Brigliadori, Luca; Bromberg, Carl Michael; Brucken, Erik; Budagov, Ioulian A; Budd, Howard Scott; Burkett, Kevin Alan; Busetto, Giovanni; Bussey, Peter John; Butti, Pierfrancesco; Buzatu, Adrian; Calamba, Aristotle; Camarda, Stefano; Campanelli, Mario; Canelli, Florencia; Carls, Benjamin; Carlsmith, Duncan L; Carosi, Roberto; Carrillo Moreno, Salvador; Casal Larana, Bruno; Casarsa, Massimo; Castro, Andrea; Catastini, Pierluigi; Cauz, Diego; Cavaliere, Viviana; Cavalli-Sforza, Matteo; Cerri, Alessandro; Cerrito, Lucio; Chen, Yen-Chu; Chertok, Maxwell Benjamin; Chiarelli, Giorgio; Chlachidze, Gouram; Cho, Kihyeon; Chokheli, Davit; Clark, Allan Geoffrey; Clarke, Christopher Joseph; Convery, Mary Elizabeth; Conway, John Stephen; Corbo, Matteo; Cordelli, Marco; Cox, Charles Alexander; Cox, David Jeremy; Cremonesi, Matteo; Cruz Alonso, Daniel; Cuevas Maestro, Javier; Culbertson, Raymond Lloyd; D'Ascenzo, Nicola; Datta, Mousumi; de Barbaro, Pawel; Demortier, Luc M; Deninno, Maria Maddalena; D'Errico, Maria; Devoto, Francesco; Di Canto, Angelo; Di Ruzza, Benedetto; Dittmann, Jay Richard; Donati, Simone; D'Onofrio, Monica; Dorigo, Mirco; Driutti, Anna; Ebina, Koji; Edgar, Ryan Christopher; Elagin, Andrey L; Erbacher, Robin D; Errede, Steven Michael; Esham, Benjamin; Farrington, Sinead Marie; Fernández Ramos, Juan Pablo; Field, Richard D; Flanagan, Gene U; Forrest, Robert David; Franklin, Melissa EB; Freeman, John Christian; Frisch, Henry J; Funakoshi, Yujiro; Galloni, Camilla; Garfinkel, Arthur F; Garosi, Paola; Gerberich, Heather Kay; Gerchtein, Elena A; Giagu, Stefano; Giakoumopoulou, Viktoria Athina; Gibson, Karen Ruth; Ginsburg, Camille Marie; Giokaris, Nikos D; Giromini, Paolo; Giurgiu, Gavril A; Glagolev, Vladimir; Glenzinski, Douglas Andrew; Gold, Michael S; Goldin, Daniel; Golossanov, Alexander; Gomez, Gervasio; Gomez-Ceballos, Guillelmo; Goncharov, Maxim T; González López, Oscar; Gorelov, Igor V; Goshaw, Alfred T; Goulianos, Konstantin A; Gramellini, Elena; Grinstein, Sebastian; Grosso-Pilcher, Carla; Group, Robert Craig; Guimaraes da Costa, Joao; Hahn, Stephen R; Han, Ji-Yeon; Happacher, Fabio; Hara, Kazuhiko; Hare, Matthew Frederick; Harr, Robert Francis; Harrington-Taber, Timothy; Hatakeyama, Kenichi; Hays, Christopher Paul; Heinrich, Joel G; Herndon, Matthew Fairbanks; Hocker, James Andrew; Hong, Ziqing; Hopkins, Walter Howard; Hou, Suen Ray; Hughes, Richard Edward; Husemann, Ulrich; Hussein, Mohammad; Huston, Joey Walter; Introzzi, Gianluca; Iori, Maurizio; Ivanov, Andrew Gennadievich; James, Eric B; Jang, Dongwook; Jayatilaka, Bodhitha Anjalike; Jeon, Eun-Ju; Jindariani, Sergo Robert; Jones, Matthew T; Joo, Kyung Kwang; Jun, Soon Yung; Junk, Thomas R; Kambeitz, Manuel; Kamon, Teruki; Karchin, Paul Edmund; Kasmi, Azeddine; Kato, Yukihiro; Ketchum, Wesley Robert; Keung, Justin Kien; Kilminster, Benjamin John; Kim, DongHee; Kim, Hyunsoo; Kim, Jieun; Kim, Min Jeong; Kim, Shin-Hong; Kim, Soo Bong; Kim, Young-Jin; Kim, Young-Kee; Kimura, Naoki; Kirby, Michael H; Knoepfel, Kyle James; Kondo, Kunitaka; Kong, Dae Jung; Konigsberg, Jacobo; Kotwal, Ashutosh Vijay; Kreps, Michal; Kroll, IJoseph; Kruse, Mark Charles; Kuhr, Thomas; Kurata, Masakazu; Laasanen, Alvin Toivo; Lammel, Stephan; Lancaster, Mark; Lannon, Kevin Patrick; Latino, Giuseppe; Lee, Hyun Su; Lee, Jaison; Leo, Sabato; Leone, Sandra; Lewis, Jonathan D; Limosani, Antonio; Lipeles, Elliot David; Lister, Alison; Liu, Hao; Liu, Qiuguang; Liu, Tiehui Ted; Lockwitz, Sarah E; Loginov, Andrey Borisovich; Lucchesi, Donatella; Lucà, Alessandra; Lueck, Jan; Lujan, Paul Joseph; Lukens, Patrick Thomas; Lungu, Gheorghe; Lys, Jeremy E; Lysak, Roman; Madrak, Robyn Leigh; Maestro, Paolo; Malik, Sarah Alam; Manca, Giulia; Manousakis-Katsikakis, Arkadios; Marchese, Luigi; Margaroli, Fabrizio; Marino, Christopher Phillip; Martínez-Perez, Mario; Matera, Keith; Mattson, Mark Edward; Mazzacane, Anna; Mazzanti, Paolo; McNulty, Ronan; Mehta, Andrew; Mehtala, Petteri; Mesropian, Christina; Miao, Ting; Mietlicki, David John; Mitra, Ankush; Miyake, Hideki; Moed, Shulamit; Moggi, Niccolo; Moon, Chang-Seong; Moore, Ronald Scott; Morello, Michael Joseph; Mukherjee, Aseet; Muller, Thomas; Murat, Pavel A; Mussini, Manuel; Nachtman, Jane Marie; Nagai, Yoshikazu; Naganoma, Junji; Nakano, Itsuo; Napier, Austin; Nett, Jason Michael; Neu, Christopher Carl; Nigmanov, Turgun S; Nodulman, Lawrence J; Noh, Seoyoung; Norniella Francisco, Olga; Oakes, Louise Beth; Oh, Seog Hwan; Oh, Young-do; Oksuzian, Iuri Artur; Okusawa, Toru; Orava, Risto Olavi; Ortolan, Lorenzo; Pagliarone, Carmine Elvezio; Palencia, Jose Enrique; Palni, Prabhakar; Papadimitriou, Vaia; Parker, William Chesluk; Pauletta, Giovanni; Paulini, Manfred; Paus, Christoph Maria Ernst; Phillips, Thomas J; Piacentino, Giovanni M; Pianori, Elisabetta; Pilot, Justin Robert; Pitts, Kevin T; Plager, Charles; Pondrom, Lee G; Poprocki, Stephen; Potamianos, Karolos Jozef; Pranko, Aliaksandr Pavlovich; Prokoshin, Fedor; Ptohos, Fotios K; Punzi, Giovanni; Ranjan, Niharika; Redondo Fernández, Ignacio; Renton, Peter B; Rescigno, Marco; Rimondi, Franco; Ristori, Luciano; Robson, Aidan; Rodriguez, Tatiana Isabel; Rolli, Simona; Ronzani, Manfredi; Roser, Robert Martin; Rosner, Jonathan L; Ruffini, Fabrizio; Ruiz Jimeno, Alberto; Russ, James S; Rusu, Vadim Liviu; Sakumoto, Willis Kazuo; Sakurai, Yuki; Santi, Lorenzo; Sato, Koji; Saveliev, Valeri; Savoy-Navarro, Aurore; Schlabach, Philip; Schmidt, Eugene E; Schwarz, Thomas A; Scodellaro, Luca; Scuri, Fabrizio; Seidel, Sally C; Seiya, Yoshihiro; Semenov, Alexei; Sforza, Federico; Shalhout, Shalhout Zaki; Shears, Tara G; Shepard, Paul F; Shimojima, Makoto; Shochet, Melvyn J; Shreyber-Tecker, Irina; Simonenko, Alexander V; Sliwa, Krzysztof Jan; Smith, John Rodgers; Snider, Frederick Douglas; Song, Hao; Sorin, Maria Veronica; St Denis, Richard Dante; Stancari, Michelle Dawn; Stentz, Dale James; Strologas, John; Sudo, Yuji; Sukhanov, Alexander I; Suslov, Igor M; Takemasa, Ken-ichi; Takeuchi, Yuji; Tang, Jian; Tecchio, Monica; Teng, Ping-Kun; Thom, Julia; Thomson, Evelyn Jean; Thukral, Vaikunth; Toback, David A; Tokar, Stanislav; Tollefson, Kirsten Anne; Tomura, Tomonobu; Tonelli, Diego; Torre, Stefano; Torretta, Donatella; Totaro, Pierluigi; Trovato, Marco; Ukegawa, Fumihiko; Uozumi, Satoru; Velev, Gueorgui; Vellidis, Konstantinos; Vernieri, Caterina; Vidal Marono, Miguel; Vilar Cortabitarte, Rocio; Vizán Garcia, Jesus Manuel; Vogel, Marcelo; Volpi, Guido; Vázquez-Valencia, Elsa Fabiola; Wagner, Peter; Wallny, Rainer S; Wang, Song-Ming; Waters, David S; Wester, William Carl; Whiteson, Daniel O; Wicklund, Arthur Barry; Wilbur, Scott; Williams, Hugh H; Wilson, Jonathan Samuel; Wilson, Peter James; Winer, Brian L; Wittich, Peter; Wolbers, Stephen A; Wolfe, Homer; Wright, Thomas Roland; Wu, Xin; Wu, Zhenbin; Yamamoto, Kazuhiro; Yamato, Daisuke; Yang, Tingjun; Yang, Un-Ki; Yang, Yu Chul; Yao, Wei-Ming; Yeh, Gong Ping; Yi, Kai; Yoh, John; Yorita, Kohei; Yoshida, Takuo; Yu, Geum Bong; Yu, Intae; Zanetti, Anna Maria; Zeng, Yu; Zhou, Chen; Zucchelli, Stefano

    2014-03-20

    A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb^-1 of integrated luminosity from proton-antiproton collisions at sqrt(s) = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 x 10^-5 for Z to \\pi^0\\gamma, 1.46 x 10^-5 for Z to \\gamma\\gamma, and 1.52 x 10^-5 for Z to \\pi^0\\pi^0. The Z to \\pi^0\\gamma\\ and Z to \\gamma\\gamma\\ limits improve by factors of 2.6 and 3.6, respectively, the most stringent results from other experiments. The Z to \\pi^0\\pi^0 branching ratio limit is the first experimental result on this decay.

  16. First search for exotic Z Boson decays into photons and neutral pions in hadron collisions.

    Science.gov (United States)

    Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Martínez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester Iii, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2014-03-21

    A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at √s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 × 10(-5) for Z → π(0)γ, 1.46 × 10(-5) for Z → γγ, and 1.52 × 10(-5) for Z → π(0)π(0). The Z → π(0)γ and Z → γγ limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z → π(0)π(0) branching ratio limit is the first experimental result on this decay.

  17. Production of neutral pions Pb+Au collisions at 158 AGeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Soualah, Rachik

    2009-06-24

    The direct photons are a particularly useful probe to search for an evidence of the Quark-Gluon Plasma formation in ultra-relativistic heavy-ion collisions. Direct photons can be extracted experimentally by measuring the large background from {pi}{sup 0} and {eta} meson decays. This thesis work represents the production of the neutral pion mesons measured with the CERES/NA45 experiment at the top SPS energy in 158 AGeV/c Pb-Au collisions. The {pi}{sup 0} {yields} {gamma}{gamma} (98.8%) is the decay channel used in the reconstruction scheme. The {pi}{sup 0} measurement is based on the data taken in the year 2000. The CERES experiment can measure the photons that convert shortly before the TPC by measuring the e{sup +}e{sup -} pairs in the TPC. The RICH2 mirror is the main converter used for this analysis. The presented analysis method describes in more details the selection of the e{sup +} and e{sup -} tracks using only the TPC information to reconstruct the converted photon. A Secondary vertex technique was developed and used to select the photons converted in the RICH2 mirror area. The extraction of the {pi}{sup 0} needs a careful study of the combinatorial background determined using the mixed event technique. The obtained invariant mass distribution of the two photons defined well the {pi}{sup 0} peak. The neutral pion transverse spectra compared to phenomenological models and other experiments validate our analysis method. (orig.)

  18. Centrality Dependence of Neutral Pion Production in 158 A GeV $^{208}Pb +^{208}Pb$ Collisions

    CERN Document Server

    Aggarwal, M.M.; Ahammed, Z.; Angelis, A.L.S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Baldine, A.; Barabach, L.; Barlag, C.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bock, R.; Bohne, E.-M.; Borocz, Z.K.; Bucher, D.; Buijs, A.; Busching, H.; Carlen, L.; Chalyshev, V.; Chattopadhyay, S.; Cherbatchev, R.; Chujo, T.; Claussen, A.; Das, A.C.; Decowski, M.P.; Djordjadze, V.; Donni, P.; Doubovik, I.; Dutta Majumdar, M.R.; El Chenawi, K.; Eliseev, S.; Enosawa, K.; Foka, P.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Gupta, S.K.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Higuchi, R.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Kampert, K.-H.; Karadjev, K.; Karpio, K.; Kato, S.; Kees, S.; Kim, H.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Krumpel, T.; Kugler, A.; Kulinich, P.; Kurata, M.; Kurita, K.; Kuzmin, N.; Langbein, I.; Lebedev, A.; Lee, Y.Y.; Lohner, H.; Luquin, L.; Mahapatra, D.P.; Manko, V.; Martin, M.; Maximov, A.; Mehdiyev, R.; Mgebrichvili, G.; Miake, Y.; Mikhalev, D.; Mishra, G.C.; Miyamoto, Y.; Morrison, D.; Mukhopadhyay, D.S.; Myalkovski, V.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Neumaier, S.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nilsson, P.; Nishimura, S.; Nomokonov, P.; Nystrand, J.; Obenshain, F.E.; Oskarsson, A.; Otterlund, I.; Pachr, M.; Parfenov, A.; Pavliouk, S.; Pietzmann, T.; Patracek, V.; Pinanaud, W.; Plasil, F.; Purschke, M.L.; Raeven, B.; Rak, J.; Raniwala, R.; Raniwala, S.; Ramamurthy, V.S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Roy, C.; Rubio, J.M.; Sako, H.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.-R.; Shabratova, G.; Sibiriak, I.; Siemiarczuk, T.; Silvermyr, D.; Sinha, B.C.; Slavine, N.; Soderstrom, K.; Solomey, N.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Stuken, D.; Sumbera, M.; Svensson, T.; Trivedi, M.D.; Tsvetkov, A.; Twenhofel, C.; Tykarski, L.; Urbahn, J.; Eijndhoven, N.v.; Nieuwenhuizen, G.J.v.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.; Voros, S.; Wyslouch, B.; Yagi, K.; Yokota, Y.; Young, G.R.

    1998-01-01

    The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system.

  19. Centrality Dependence of Neutral Pion Production in 158A GeV {sup 208}Pb+{sup 208}Pb Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, M.M.; Bhatia, V.S. [University of Panjab, Chandigarh 160014 (India); Agnihotri, A.; Bhalla, K.B.; Gupta, S.K.; Raniwala, R.; Raniwala, S. [University of Rajasthan, Jaipur 302004 (India); Ahammed, Z.; Chattopadhyay, S.; Das, A.C.; Dutta Majumdar, M.R.; Ganti, M.S.; Mukhopadhyay, D.S.; Nayak, T.K.; Sinha, B.C.; Trivedi, M.D.; Viyogi, Y.P. [Variable Energy Cyclotron Centre, Calcutta 700 064 (India); Angelis, A.L.; Donni, P.; Foka, P.; Kalechofsky, H.; Martin, M.; Naef, H.; Rosselet, L.; Rubio, J.M.; Solomey, N.; Voeroes, S. [University of Geneva, CH-1211 Geneva 4 (Switzerland); Antonenko, V.; Cherbatchev, R.; Doubovik, I.; Fokin, S.; Ippolitov, M.; Karadjev, K.; Koutcheryaev, I.; Lebedev, A.; Manko, V.; Mgebrichvili, G.; Nianine, A.; Sibiriak, I.; Tsvetkov, A.; Vinogradov, A. [RRC (Kurchatov), RU-123182 Moscow (Russia); Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Baldine, A.; Barabach, L.; Batiounia, B.; Chalyshev, V.; Djordjadze, V.; Frolov, V.; Gavrishchuk, O.; Guskov, B.; Kosarev, I.; Kuzmin, N.; Maximov, A.; Mehdiyev, R.; Mikhalev, D.; Myalkovski, V.; Nikitine, V.; Nikolaev, S.; Nomokonov, P.; Parfenov, A.; Pavliouk, S.; Roufanov, I.; Shabratova, G.; Slavine, N.; Vodopianov, A. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russia); Awes, T.C.; Kim, H.; Plasil, F.; Stankus, P.; Young, G.R. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States); Baba, P.V.; Badyal, S.K.; Rao, N.K.; Sambyal, S.S. [University of Jammu, Jammu 180001 (India); Barlag, C.; Bathe, S.; Blume, C.; Bohne, E.; Boeroecz, Z.K.; Bucher, D.; Buesching, H.; Claussen, A.; Glasow, R.; Kampert, K.; Kees, S.; Kruempel, T.; Pietzmann, T.; Reygers, K.; Santo, R.; Schlagheck, H.; Stueken, D. [University of Muenster, D-48149 Muenster (Germany); Bernier, T.; Gutbrod, H.H.; Luquin, L.; Nayak, S.K.; Pinanaud, W.; Retiere, F.; Roy, C. [SUBATECH, Ecole des Mines, Nantes (France); Bock, R.; Kolb, B.W.; Langbein, I.; Lee, Y.Y.; Neumaier, S.; and others

    1998-11-01

    The production of neutral pions in 158A GeV {sup 208}Pb+ {sup 208}Pb collisions has been studied in the WA98 experiment at the CERN Super Proton Synchrotron (SPS). Transverse momentum spectra are studied for the range 0.3{le}m{sub T}{minus}m{sub 0}{le}4.0 GeV /c . The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30thinspthinspparticipating nucleons. This is most naturally explained by assuming an equilibrated system. {copyright} {ital 1998} {ital The American Physical Society }

  20. A Measurement of Neutrino-Induced Charged-Current Neutral Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Robert H. [Univ. of Colorado, Boulder, CO (United States)

    2010-01-01

    This work presents the first comprehensive measurement of neutrino-induced charged-current neutral pion production (CCπ0) off a nuclear target. The Mini Booster Neutrino Experiment (MiniBooNE) and Booster Neutrino Beam (BNB) are discussed in detail. MiniBooNE is a high-statistics (~ 1, 000, 000 interactions) low-energy (Evϵ 2 0.5 - 2.0 GeV) neutrino experiment located at Fermilab. The method for selecting and reconstructing CCπ0 events is presented. The π0 and μ- are fully reconstructed in the final state allowing for the measurement of, among other things, the neutrino energy. The total observable CCπ0 cross-section is presented as a function of neutrino energy, along with five differential cross-sections in terms of the final state kinematics and Q2. The results are combined to yield a flux-averaged total cross-section of <σ>Φ = (9.2 ± 0.3stat. ± 1.5syst.) × 10-39 cm2/CH2 at energy 965 MeV. These measurements will aid future neutrino experiments with the prediction of their neutrino interaction rates.

  1. Inclusive Photoproduction of Neutral Pions in the Photon Hemisphere at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Bernardi, G.; Berndt, T.; Bertrand-Coremans, G.; Bizot, J.C.; Borras, K.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; Collard, C.; Contreras, J.G.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; David, M.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dixon, P.; Dodonov, V.; Donovan, K.T.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Ebert, J.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferrarotto, F.; Ferron, S.; Fleischer, M.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazaryan, Samvel; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haustein, V.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hilgers, M.; Hiller, K.H.; Hilton, C.D.; Hladky, J.; Hoting, P.; Hoffmann, D.; Hoprich, W.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Kaufmann, O.; Kausch, M.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Knies, G.; Koblitz, B.; Kolanoski, H.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Krasny, M.W.; Krehbiel, H.; Kroseberg, J.; Krucker, D.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Kutuev, R.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lebedev, A.; Leissner, B.; Lemaitre, V.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; Lobo, G.; Lobodzinska, E.; Lobodzinski, B.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, A.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, D.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Negri, I.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Passaggio, S.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; Solochenko, V.; Solovev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Sutton, J.P.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; von Dombrowski, S.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wollatz, H.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

    2001-01-01

    The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman x of the pizero mesons at an average photon--proton centre-of-mass energy of 208 GeV and for photon virtualities below Q^2=0.01 GeV^2. The pizero measurement extends the range covered by previous charged particle measurements at HERA by two units of rapidity in the photon direction down to a value of -5.5 in the gamma p centre-of-mass frame. The pizero transverse momentum distribution is well described over the whole measured range by a power law ansatz, while an exponential fit falls below the data at transverse momentum values above 1.5 GeV/c. Good agreement with the predictions of the Monte Carlo models PYTHIA and PHOJET is found. In the context of the PYTHIA model the data are inconsistent with large intrinsic transverse momentum values in the photon.

  2. Proton-Proton Interaction Through the Neutral Pion Production Channel from Threshold to 1 GEV

    Science.gov (United States)

    Rigney, Micheal M.

    1992-01-01

    Total cross sections for the reaction vec ppto pppi^circ have been measured for polarized proton incident energies ranging from the single pion production threshold to 1 scGe scV. This was accomplished by use of a new neutral meson spectrometer called scSPES0-2pi. This spectrometer detector the two gamma -rays of the decay of the pi^circ in coincidence. The experiment was performed at the synchrotron of the Laboratoire National Saturne in Saclay, France. The results show that the total cross section is highly dependent on the detection efficiency of the spectrometer. This work also describes a calibration experiment that was performed with a setup of the scSPES0-2 pi spectrometer. This calibration experiment took place at the tagged photon beam of the scPHOENICS experiment at the scELSA accelerator facilities in Bonn, Germany. The results of this experiment is compared with the results from an Electron Gamma Shower scEGS simulation code. The simulation and the experiment are in good qualitative agreement. Finally, an appendix has been written describing in detail the Limited Streamer Tube (scLST) subsystem of the spectrometer. This gas detector system is used to locate where the shower was initiated. The complete subsystem of the scLST is not described anywhere else.

  3. Neutral meson measurement using different neutral pion reconstruction techniques in ALICE in pp collisions at $\\sqrt s = 7$ TeV

    CERN Document Server

    Jonas, Florian

    2017-01-01

    In this analysis, which is carried out as part of a summer student project, the $\\omega$ and $\\eta$ mesons are measured in pp collisions at $\\sqrt s = 7$ TeV using ALICE's two calorimeters PHOS and EMCal, the so called Photon Conversion Method (PCM) and two hybrid methods that combine one photon that was reconstructed with PCM and the other photon measured with the different calorimeters for neutral pion reconstruction. The analysis was carried out on LHC data from 2010 resulting in visible peaks for all mentioned methods. Investigations of the invariant mass distributions using Monte Carlo Event Generator PYTHIA6 show a main contribution to the background by false identifications of neutral pions, that are reduced by stronger cuts on the photon pairs invariant-mass. Furthermore, the chain of afterburners that was put in place to further process the extracted peaks and compare the different reconstruction methods is demonstrated.

  4. Measurement of muon neutrino and antineutrino induced single neutral pion production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Colin E. [Yale Univ., New Haven, CT (United States)

    2011-05-01

    Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for νμ → νe oscillation - a channel that may yield insight into the vanishingly small mixing parameter θ13, CP violation, and the neutrino mass hierarchy - are particularly susceptible to contamination from neutral current single π0 (NC 1π0) production. Unfortunately, the available data concerning NC 1π0 production are limited in scope and statistics. Without satisfactory constraints, theoretical models of NC 1π0 production yield substantially differing predictions in the critical Eν ~ 1 GeV regime. Additional investigation of this interaction can ameliorate the current deficiencies. The Mini Booster Neutrino Experiment (MiniBooNE) is a short-baseline neutrino oscillation search operating at the Fermi National Accelerator Laboratory (Fermilab). While the oscillation search is the principal charge of the MiniBooNE collaboration, the extensive data (~ 106 neutrino events) offer a rich resource with which to conduct neutrino cross section measurements. This work concerns the measurement of both neutrino and antineutrino NC 1π0 production cross sections at MiniBooNE. The size of the event samples used in the analysis exceeds that of all other similar experiments combined by an order of magnitude. We present the first measurements of the absolute NC 1π0 cross section as well as the first differential cross sections in both neutrino and antineutrino mode. Specifically, we measure single differential cross sections with respect to pion momentum and pion angle. We find the

  5. Photon flux determination for a precision measurement of the neutral pion lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Teymurazyan, Aram [Univ. of Kentucky, Lexington, KY (United States)

    2008-01-01

    The Jefferson Lab Hall B PrimEx Collaboration is using tagged photons to perform a 1.4% level measurement of the absolute cross section for the photo-production of neutral pions in the Coulomb field of a nucleus as a test of Chiral Perturbation Theory. Such a high precision pushes the limits of the photon tagging technique in regards to the determination of the absolute photon flux. A multifaceted approach to this problem has included measuring the absolute tagging ratios with a Total Absorption Counter (TAC) as well as relative tagging ratios with a Pair Spectrometer (PS), and determining the rate of the tagging counters using multi-hit TDC's and a clock trigger. This enables the determination of the absolute tagged photon flux for the PrimEx experiment with uncertainty of ~ 1.0%, which is unprecedented. In view of the stringent constraints on the required precision of the photon flux for this experiment, periodicmeasurements of the pair production cross section were performed throughout the run. In these measurements, both the photon energy and flux were determined by the Jefferson Lab Hall B tagger, and the electron-positron pairs were swept by a magnetic field and detected in the new 1728 channel hybrid calorimeter (HyCal). The pair production crosssection was extracted with an uncertainty of ~ 2%, producing an agreement with theoretical calculations at the level of ~ 2%. This measurement provided a unique opportunity to verify the photon flux determination procedure for the PrimEx experiment.

  6. Suppression of High-pT Neutral Pions in Central Pb+Pb Collisions at sqrt{s_NN} = 17.3 GeV

    CERN Document Server

    Aggarwal, M.M.; Angelis, A.L.S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Bathe, S.; Batiounia, B.; Baumann, C.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bucher, D.; Busching, H.; Carlen, L.; Chattopadhyay, S.; Decowski, M.P.; Delagrange, H.; Donni, P.; Dutta Majumdar, M.R.; El Chenawi, K.; Dubey, A.K.; Enosawa, K.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Karadjev, K.; Karpio, K.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kurata, M.; Lebedev, A.; Lohner, H.; Luquin, L.; Mahapatra, D.P.; Manko, V.; Martin, M.; Martinez, G.; Maximov, A.; Miake, Y.; Mishra, G.C.; Mohanty, B.; Mora, M.J.; Morrison, D.; Mukhanova, T.; Mukhopadhyay, D.S.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nilsson, P.; Nishimura, S.; Nomokonov, P.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Pavliouk, S.; Peitzmann, T.; Peressounko, D.; Petracek, V.; Phatak, S.C.; Pinganaud, W.; Plasil, F.; Purschke, M.L.; Rak, J.; Rammler, M.; Raniwala, R.; Raniwala, S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Roy, C.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.R.; Schutz, Y.; Shabratova, G.; Shah, T.H.; Sibiriak, I.; Siemiarczuk, T.; Silvermyr, D.; Sinha, B.C.; Slavine, N.; Soderstrom, K.; Sood, G.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Sumbera, M.; Svensson, T.; Tsvetkov, A.; Tykarski, L.; van de Pijll, E.C.; van Eijndhoven, N.; van Nieuwenhuizen, G.J.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.; Voros, S.; Wyslouch, B.; Young, G.R.

    2007-01-01

    Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt{s_NN} = 17.4 GeV at mid-rapidity (2.3 2 GeV/c is consistent with the p+C or p+Pb yields scaled with the number of inelastic nucleon-nucleon collisions, while for central Pb+Pb collisions with N_{part} > 300 the pion yield is suppressed.

  7. Transverse mass distributions of neutral pions from $^{208}$Pb-induced reactions at 158$\\cdot A$ GeV

    CERN Document Server

    Aggarwal, M.M.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bucher, D.; Busching, H.; Carlen, L.; Chattopadhyay, S.; Decowski, M.P.; Delagrange, H.; Donni, P.; Dutta Majumdar, M.R.; El Chenawi, K.; Enosawa, K.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Karadjev, K.; Karpio, K.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kurata, M.; Lebedev, A.; Lohner, H.; Mahapatra, D.P.; Manko, V.; Martin, M.; Martinez, G.; Maximov, A.; Miake, Y.; Mishra, G.C.; Mohanty, B.; Mora, M.J.; Morrison, Douglas R.O.; Mukhanova, T.; Mukhopadhyay, D.S.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nilsson, P.; Nishimura, S.; Nomokonov, P.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Peitzmann, T.; Peressounko, D.; Petracek, V.; Plasil, F.; Purschke, M.L.; Rak, J.; Raniwala, R.; Raniwala, S.; Rao, N.K.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.R.; Schutz, Y.; Shabratova, G.; Shah, T.H.; Sibiriak, I.; Siemiarczuk, T.; Silvermyr, D.; Sinha, B.C.; Slavine, N.; Soderstrom, K.; Sood, G.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Sumbera, M.; Svensson, T.; Tsvetkov, A.; Tykarski, L.; Van den Pijll, E.C.; Van Eijndhoven, N.; Van Nieuwenhuizen, G.J.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.S.; Voros, S.; Wyslouch, B.; Young, G.R.

    2002-01-01

    Results on transverse mass spectra of neutral pions measured at central rapidity are presented for impact parameter selected 158$\\cdot A$ GeV Pb + Pb, and Pb + Nb collisions. The distributions cover the range $0.5 \\mathrm{GeV}/c^{2} \\le m_{T} - m_{0} \\le 4 \\mathrm{GeV}/c^{2}$. The change of the spectral shape with centrality is studied in detail. In going from peripheral to medium central collisions there is a nuclear enhancement increasing with transverse mass similar to the well known Cronin effect, while for very central collisions this enhancement appears to be weaker than expected.

  8. Measurement of the azimuthal anisotropy of neutral pions in PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Staykova, Zlatka; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Reis, Thomas; Thomas, Laurent; Vander Marcken, Gil; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Verwilligen, Piet; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; De Jesus Damiao, Dilson; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Melo Da Costa, Eliza; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zhu, Bo; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Millischer, Laurent; Nayak, Aruna; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Baffioni, Stephanie; Beaudette, Florian; Benhabib, Lamia; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Daci, Nadir; Dahms, Torsten; Dobrzynski, Ludwik; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Naranjo, Ivo Nicolas; Nguyen, Matthew; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Veelken, Christian; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Ferro, Cristina; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Juillot, Pierre; Le Bihan, Anne-Catherine; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Beauceron, Stephanie; Beaupere, Nicolas; Bondu, Olivier; Boudoul, Gaelle; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Fay, Jean; Gascon, Susan; Gouzevitch, Maxime; Ille, Bernard; Kurca, Tibor; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tschudi, Yohann; Verdier, Patrice; Viret, Sébastien; Tsamalaidze, Zviad; Anagnostou, Georgios; Beranek, Sarah; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Wittmer, Bruno; Zhukov, Valery; Ata, Metin; Caudron, Julien; Dietz-Laursonn, Erik; Duchardt, Deborah; Erdmann, Martin; Fischer, Robert; Güth, Andreas; Hebbeker, Thomas; Heidemann, Carsten; Hoepfner, Kerstin; Klingebiel, Dennis; Kreuzer, Peter; Magass, Carsten; Merschmeyer, Markus; Meyer, Arnd; Olschewski, Mark; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Weber, Martin; Bontenackels, Michael; Cherepanov, Vladimir; Flügge, Günter; Geenen, Heiko; Geisler, Matthias; Haj Ahmad, Wael; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Kuessel, Yvonne; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Sauerland, Philip; Stahl, Achim; Aldaya Martin, Maria; Behr, Joerg; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Bethani, Agni; Borras, Kerstin; Burgmeier, Armin; Cakir, Altan; Calligaris, Luigi; Campbell, Alan; Castro, Elena; Costanza, Francesco; Dammann, Dirk; Diez Pardos, Carmen; Eckerlin, Guenter; Eckstein, Doris; Flucke, Gero; Geiser, Achim; Glushkov, Ivan; Gunnellini, Paolo; Habib, Shiraz; Hauk, Johannes; Hellwig, Gregor; Jung, Hannes; Kasemann, Matthias; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krämer, Mira; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Lutz, Benjamin; Mankel, Rainer; Marfin, Ihar; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Naumann-Emme, Sebastian; Olzem, Jan; Perrey, Hanno; Petrukhin, Alexey; Pitzl, Daniel; Raspereza, Alexei; Ribeiro Cipriano, Pedro M; Riedl, Caroline; Ron, Elias; Rosin, Michele; Salfeld-Nebgen, Jakob; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Spiridonov, Alexander; Stein, Matthias; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Blobel, Volker; Draeger, Jula; Enderle, Holger; Erfle, Joachim; Gebbert, Ulla; Görner, Martin; Hermanns, Thomas; Höing, Rebekka Sophie; Kaschube, Kolja; Kaussen, Gordon; Kirschenmann, Henning; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Nowak, Friederike; Peiffer, Thomas; Pietsch, Niklas; Rathjens, Denis; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schlieckau, Eike; Schmidt, Alexander; Schröder, Matthias; Schum, Torben; Seidel, Markus; Sola, Valentina; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Vanelderen, Lukas; Barth, Christian; Berger, Joram; Böser, Christian; Chwalek, Thorsten; De Boer, Wim; Descroix, Alexis; Dierlamm, Alexander; Feindt, Michael; Guthoff, Moritz; Hackstein, Christoph; Hartmann, Frank; Hauth, Thomas; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Katkov, Igor; Komaragiri, Jyothsna Rani; Lobelle Pardo, Patricia; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Nürnberg, Andreas; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Ratnikova, Natalia; Röcker, Steffen; Scheurer, Armin; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Ulrich, Ralf; Wagner-Kuhr, Jeannine; Wayand, Stefan; Weiler, Thomas; Zeise, Manuel; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Ntomari, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Saoulidou, Niki; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Bencze, Gyorgy; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Sikler, Ferenc; Veszpremi, Viktor; Vesztergombi, Gyorgy; Beni, Noemi; Czellar, Sandor; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Karancsi, János; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Gupta, Ruchi; Bansal, Monika; Kaur, Manjit; Mehta, Manuk Zubin; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Singh, Jasbir; Kumar, Ashok; Kumar, Arun; Ahuja, Sudha; Bhardwaj, Ashutosh; Choudhary, Brajesh C; Malhotra, Shivali; Naimuddin, Md; Ranjan, Kirti; Sharma, Varun; Shivpuri, Ram Krishen; Banerjee, Sunanda; Bhattacharya, Satyaki; Dutta, Suchandra; Gomber, Bhawna; Jain, Sandhya; Jain, Shilpi; Khurana, Raman; Sarkar, Subir; Sharan, Manoj; Abdulsalam, Abdulla; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kumar, Vineet; Mehta, Pourus; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Ganguly, Sanmay; Guchait, Monoranjan; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Parida, Bibhuti; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Hesari, Hoda; Jafari, Abideh; Khakzad, Mohsen; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Chhibra, Simranjit Singh; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pompili, Alexis; Pugliese, Gabriella; Selvaggi, Giovanna; Silvestris, Lucia; Singh, Gurpreet; Venditti, Rosamaria; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Grandi, Claudio; Guiducci, Luigi; Marcellini, Stefano; Masetti, Gianni; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gian Piero; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Gonzi, Sandro; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Tosi, Silvano; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Fiorendi, Sara; Gennai, Simone; Ghezzi, Alessio; Malvezzi, Sandra; Manzoni, Riccardo Andrea; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Sala, Silvano; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Carrillo Montoya, Camilo Andres; Cavallo, Nicola; De Cosa, Annapaola; Dogangun, Oktay; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Meola, Sabino; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Checchia, Paolo; Dorigo, Tommaso; Dosselli, Umberto; Gasparini, Fabrizio; Gozzelino, Andrea; Gulmini, Michele; Kanishchev, Konstantin; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Maron, Gaetano; Meneguzzo, Anna Teresa; Nespolo, Massimo; Pazzini, Jacopo; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Vanini, Sara; Zotto, Pierluigi; Zumerle, Gianni; Gabusi, Michele; Ratti, Sergio P; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Biasini, Maurizio; Bilei, Gian Mario; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Romeo, Francesco; Saha, Anirban; Santocchia, Attilio; Spiezia, Aniello; Taroni, Silvia; Azzurri, Paolo; Bagliesi, Giuseppe; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Rizzi, Andrea; Serban, Alin Titus; Spagnolo, Paolo; Squillacioti, Paola; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Diemoz, Marcella; Fanelli, Cristiano; Grassi, Marco; Longo, Egidio; Meridiani, Paolo; Micheli, Francesco; Nourbakhsh, Shervin; Organtini, Giovanni; Paramatti, Riccardo; Rahatlou, Shahram; Sigamani, Michael; Soffi, Livia; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Cartiglia, Nicolo; Costa, Marco; Dattola, Domenico; Demaria, Natale; Mariotti, Chiara; Maselli, Silvia; Migliore, Ernesto; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Potenza, Alberto; Romero, Alessandra; Sacchi, Roberto; Solano, Ada; Staiano, Amedeo; Vilela Pereira, Antonio; Belforte, Stefano; Candelise, Vieri; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Marone, Matteo; Montanino, Damiana; Penzo, Aldo; Schizzi, Andrea; Heo, Seong Gu; Kim, Tae Yeon; Nam, Soon-Kwon; Chang, Sunghyun; Kim, Dong Hee; Kim, Gui Nyun; Kong, Dae Jung; Park, Hyangkyu; Ro, Sang-Ryul; Son, Dong-Chul; Son, Taejin; Kim, Jae Yool; Kim, Zero Jaeho; Song, Sanghyeon; Choi, Suyong; Gyun, Dooyeon; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Choi, Minkyoo; Kim, Ji Hyun; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Cho, Yongjin; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Min Suk; Kwon, Eunhyang; Lee, Byounghoon; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Juodagalvis, Andrius; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Lopez-Fernandez, Ricardo; Magaña Villalba, Ricardo; Martínez-Ortega, Jorge; Sánchez-Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A; Krofcheck, David; Bell, Alan James; Butler, Philip H; Doesburg, Robert; Reucroft, Steve; Silverwood, Hamish; Ahmad, Muhammad; Ansari, Muhammad Hamid; Asghar, Muhammad Irfan; Hoorani, Hafeez R; Khalid, Shoaib; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Shah, Mehar Ali; Shoaib, Muhammad; Bialkowska, Helena; Boimska, Bozena; Frueboes, Tomasz; Gokieli, Ryszard; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Brona, Grzegorz; Bunkowski, Karol; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Almeida, Nuno; Bargassa, Pedrame; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Seixas, Joao; Varela, Joao; Vischia, Pietro; Afanasiev, Serguei; Bunin, Pavel; Gavrilenko, Mikhail; Golutvin, Igor; Gorbunov, Ilya; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Malakhov, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Evstyukhin, Sergey; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Vorobyev, Andrey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Tlisov, Danila; Toropin, Alexander; Epshteyn, Vladimir; Erofeeva, Maria; Gavrilov, Vladimir; Kossov, Mikhail; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Belyaev, Andrey; Boos, Edouard; Ershov, Alexander; Gribushin, Andrey; Klyukhin, Vyacheslav; Kodolova, Olga; Korotkikh, Vladimir; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Popov, Andrey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Vardanyan, Irina; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Vinogradov, Alexey; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Ekmedzic, Marko; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Quintario Olmeda, Adrián; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Senghi Soares, Mara; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Brun, Hugues; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Piedra Gomez, Jonatan; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Graziano, Alberto; Jorda, Clara; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Benitez, Jose F; Bernet, Colin; Bianchi, Giovanni; Bloch, Philippe; Bocci, Andrea; Bonato, Alessio; Botta, Cristina; Breuker, Horst; Camporesi, Tiziano; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; D'Enterria, David; Dabrowski, Anne; De Roeck, Albert; Di Guida, Salvatore; Dobson, Marc; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Georgiou, Georgios; Giffels, Manuel; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Giunta, Marina; Glege, Frank; Gomez-Reino Garrido, Robert; Govoni, Pietro; Gowdy, Stephen; Guida, Roberto; Hansen, Magnus; Harris, Philip; Hartl, Christian; Harvey, John; Hegner, Benedikt; Hinzmann, Andreas; Innocente, Vincenzo; Janot, Patrick; Kaadze, Ketino; Karavakis, Edward; Kousouris, Konstantinos; Lecoq, Paul; Lee, Yen-Jie; Lenzi, Piergiulio; Lourenco, Carlos; Maki, Tuula; Malberti, Martina; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Musella, Pasquale; Nesvold, Erik; Orimoto, Toyoko; Orsini, Luciano; Palencia Cortezon, Enrique; Perez, Emmanuelle; Perrozzi, Luca; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Piparo, Danilo; Polese, Giovanni; Quertenmont, Loic; Racz, Attila; Reece, William; Rodrigues Antunes, Joao; Rolandi, Gigi; Rommerskirchen, Tanja; Rovelli, Chiara; Rovere, Marco; Sakulin, Hannes; Santanastasio, Francesco; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sekmen, Sezen; Sharma, Archana; Siegrist, Patrice; Silva, Pedro; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Tsirou, Andromachi; Veres, Gabor Istvan; Vlimant, Jean-Roch; Wöhri, Hermine Katharina; Worm, Steven; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Gabathuler, Kurt; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; König, Stefan; Kotlinski, Danek; Langenegger, Urs; Meier, Frank; Renker, Dieter; Rohe, Tilman; Sibille, Jennifer; Bäni, Lukas; Bortignon, Pierluigi; Buchmann, Marco-Andrea; Casal, Bruno; Chanon, Nicolas; Deisher, Amanda; Dissertori, Günther; Dittmar, Michael; Donegà, Mauro; Dünser, Marc; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Hits, Dmitry; Lecomte, Pierre; Lustermann, Werner; Marini, Andrea Carlo; Martinez Ruiz del Arbol, Pablo; Mohr, Niklas; Moortgat, Filip; Nägeli, Christoph; Nef, Pascal; Nessi-Tedaldi, Francesca; Pandolfi, Francesco; Pape, Luc; Pauss, Felicitas; Peruzzi, Marco; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Starodumov, Andrei; Stieger, Benjamin; Takahashi, Maiko; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Hannsjoerg Artur; Wehrli, Lukas; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Otiougova, Polina; Robmann, Peter; Snoek, Hella; Tupputi, Salvatore; Verzetti, Mauro; Chang, Yuan-Hann; Chen, Kuan-Hsin; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Zong-Kai; Lu, Yun-Ju; Mekterovic, Darko; Singh, Anil; Volpe, Roberta; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Dietz, Charles; Grundler, Ulysses; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Majumder, Devdatta; Petrakou, Eleni; Shi, Xin; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wan, Xia; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Karaman, Turker; Karapinar, Guler; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Sunar Cerci, Deniz; 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Kellogg, Richard G; Kirn, Malina; Kolberg, Ted; Lu, Ying; Marionneau, Matthieu; Mignerey, Alice; Pedro, Kevin; Peterman, Alison; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C; Twedt, Elizabeth; Apyan, Aram; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Kim, Yongsun; Klute, Markus; Krajczar, Krisztian; Li, Wei; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Stöckli, Fabian; Sumorok, Konstanty; Sung, Kevin; Velicanu, Dragos; Wenger, Edward Allen; Wolf, Roger; Wyslouch, Bolek; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cooper, Seth; Dahmes, Bryan; De Benedetti, Abraham; Franzoni, Giovanni; Gude, Alexander; Kao, Shih-Chuan; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Pastika, Nathaniel; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Tambe, Norbert; Turkewitz, Jared; Cremaldi, Lucien Marcus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Avdeeva, Ekaterina; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R; Dominguez, Aaron; Eads, Michael; Keller, Jason; Kravchenko, Ilya; Lazo-Flores, Jose; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Jain, Supriya; Kharchilava, Avto; Kumar, Ashish; Shipkowski, Simon Peter; Smith, Kenneth; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Chasco, Matthew; Haley, Joseph; Nash, David; Trocino, Daniele; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Mucia, Nicholas; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Brinkerhoff, Andrew; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Lannon, Kevin; Luo, Wuming; 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Halkiadakis, Eva; Hidas, Dean; Lath, Amitabh; Panwalkar, Shruti; Park, Michael; Patel, Rishi; Rekovic, Vladimir; Robles, Jorge; Rose, Keith; Salur, Sevil; Schnetzer, Steve; Seitz, Claudia; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Eusebi, Ricardo; Flanagan, Will; Gilmore, Jason; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Perloff, Alexx; Roe, Jeffrey; Safonov, Alexei; Sakuma, Tai; Sengupta, Sinjini; Suarez, Indara; Tatarinov, Aysen; Toback, David; Akchurin, Nural; Damgov, Jordan; Dudero, Phillip Russell; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Libeiro, Terence; Roh, Youn; Volobouev, Igor; Appelt, Eric; Delannoy, Andrés G; Florez, Carlos; Greene, Senta; Gurrola, Alfredo; Johns, Willard; Johnston, Cody; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sharma, Monika; Sheldon, Paul; Snook, Benjamin; Tuo, Shengquan; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Cox, Bradley; Francis, Brian; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Wood, John; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Kottachchi Kankanamge Don, Chamath; Lamichhane, Pramod; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Belknap, Donald; Borrello, Laura; Carlsmith, Duncan; Cepeda, Maria; Dasu, Sridhara; Friis, Evan; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Palmonari, Francesco; Pierro, Giuseppe Antonio; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua

    2013-01-22

    First measurements of the azimuthal anisotropy of neutral pions produced in PbPb collisions at a center-of-mass energy of $\\sqrt{s_{NN}}$ = 2.76 TeV are presented. The amplitudes of the second Fourier component ($v_2$) of the neutral pion azimuthal distributions are extracted using an event-plane technique. The values of $v_2$ are studied as a function of the neutral pion transverse momentum ($p_T$) for different classes of collision centrality in the kinematic range 1.6 < $p_T$ < 8.0 GeV, within the pseudorapidity interval |$\\eta$| < 0.8. The CMS measurements of $v_2(p_T)$ are similar to previously reported neutral pion azimuthal anisotropy results from $\\sqrt{s_{NN}}$ = 200 GeV AuAu collisions at RHIC, despite a factor of about 14 increase in the center-of-mass energy. In the momentum range 2.5 < $p_T$ < 5.0 GeV, the neutral pion anisotropies are found to be smaller than those observed by CMS for inclusive charged particles.

  9. Single neutral pion production by charged-current ν¯μ interactions on hydrocarbon at 〈Eν〉=3.6 GeV

    Directory of Open Access Journals (Sweden)

    T. Le

    2015-10-01

    Full Text Available Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH is studied using the MINERvA detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for ν¯e appearance oscillation experiments. The differential cross sections for π0 momentum and production angle, for events with a single observed π0 and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the π0 kinematics for this process.

  10. Measurements of longitudinal and transverse momentum distributions for neutral pions in the forward-rapidity region with the LHCf detector

    CERN Document Server

    Adriani, O.; Bonechi, L.; Bongi, M.; D'Alessandro, R.; Del Prete, M.; Haguenauer, M.; Itow, Y.; Kasahara, K.; Kawade, K.; Makino, Y.; Masuda, K.; Matsubayashi, E.; Menjo, H.; Mitsuka, G.; Muraki, Y.; Papini, P.; Perrot, A.L.; Ricciarini, S.; Sako, T.; Sakurai, N.; Suzuki, T.; Tamura, T.; Tiberio, A.; Torii, S.; Tricomi, A.; Turner, W.C.; Zhou, Q.D.

    2016-01-01

    The transverse and longitudinal momentum distributions for inclusive neutral pions in the very forward rapidity region have been measured with the Large Hadron Collider forward detector in proton-proton collisions at $\\sqrt{s}=$ 2.76 and 7 TeV and in proton-lead collisions at nucleon-nucleon center-of-mass energies of $\\sqrt{s_\\text{NN}}=$ 5.02 TeV at the LHC. Such momentum distributions in proton-proton collisions are compatible with the hypotheses of limiting fragmentation and Feynman scaling. A sizable suppression of the production of neutral pions, after taking into account ultraperipheral collisions, is found in the transverse and longitudinal momentum distributions obtained in proton-lead collisions. This leads to a strong nuclear modification factor value of about 0.1-0.3. The experimental measurements presented in this paper provide a benchmark for the hadronic interaction Monte Carlo simulations codes that are used for the simulation of air showers.

  11. Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Fuchey, Eric [Blaise Pascal Univ., Aubiere (France)

    2010-06-01

    The past decade has seen a strong evolution of the study of the hadron structure through exclusive processes, allowing to access to a more complete description of this structure. Exclusive processes include DVCS (Deeply Virtual Compton Scattering) as well as hard exclusive meson production. This document is particularly focussed on the latter, and more particularly on exclusive neutral pion production. In this thesis is described the analysis of triple coincidence events H(e, e'γγ)X, which were a consequent by-product of the DVCS experiment which occured during Fall 2004 at Jefferson Lab Hall A, to extract the ep → epπ0 cross section. This cross section has been measured at two values of four-momentum transfer Q2 = 1.9 GeV2 and Q2 = 2.3 GeV2. The statistical precision for these measurements is achieved at better than 5 %. The kinematic range allows to study the evolution of the extracted cross section as a function of Q2 and W. Results are be confronted with Regge inspired calculations and Generalized (GPD) predictions. An intepretation of our

  12. Measurement of forward neutral pion transverse momentum spectra for $\\sqrt{s}$ = 7TeV proton-proton collisions at LHC

    CERN Document Server

    Adriani, O.; Bongi, M.; Castellini, G.; D'Alessandro, R.; Fukatsu, K.; Haguenauer, M.; Iso, T.; Itow, Y.; Kasahara, K.; Kawade, K.; Mase, T.; Masuda, K.; Menjo, H.; Mitsuka, G.; Muraki, Y.; Noda, K.; Papini, P.; Perrot, A.-L.; Ricciarini, S.; Sako, T.; Shimizu, Y.; Suzuki, K.; Suzuki, T.; Taki, K.; Tamura, T.; Torii, S.; Tricomi, A.; Turner, W.C.

    2012-01-01

    The inclusive production rate of neutral pions in the rapidity range greater than $y=8.9$ has been measured by the Large Hadron Collider forward (LHCf) experiment during LHC $\\sqrt{s}=7$\\,TeV proton-proton collision operation in early 2010. This paper presents the transverse momentum spectra of the neutral pions. The spectra from two independent LHCf detectors are consistent with each other and serve as a cross check of the data. The transverse momentum spectra are also compared with the predictions of several hadronic interaction models that are often used for high energy particle physics and for modeling ultra-high-energy cosmic-ray showers.

  13. Magnetic polarizability of pion

    Directory of Open Access Journals (Sweden)

    E.V. Luschevskaya

    2016-10-01

    Full Text Available We explore the energy dependence of π mesons off the background Abelian magnetic field on the base of quenched SU(3 lattice gauge theory and calculate the magnetic dipole polarizability of charged and neutral pions for various lattice volumes and lattice spacings. The contribution of the magnetic hyperpolarizability to the neutral pion energy has been also found.

  14. Detailed study of high-pT neutral pion suppression and azimuthal anisotropy in Au+Au collisions at VsNN=200 GeV

    NARCIS (Netherlands)

    Peitzmann, T.|info:eu-repo/dai/nl/304833959

    2007-01-01

    Measurements of neutral pion (π0) production at midrapidity in VsNN=200 GeV Au+Au collisions as a function of transverse momentum, pT, collision centrality, and angle with respect to reaction plane are presented. The data represent the final π0 results from the PHENIX experiment for the first RHIC

  15. Study of prompt photon and neutral pion production in photon-photon scattering with the OPAL experiment

    CERN Document Server

    Lillich, Joachim

    2003-01-01

    For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of mass energies between 183 GeV and 209 GeV. The total inclusive production cross-section for isolated prompt photons in the kinematic range of transverse momentum > 3.0 GeV and the absolut value of pseudorapidity <1 is determined to be (0.32 +- 0.04 (stat) +- 0.04 (sys)) pb. Differential cross-sections are compared to the predictions of a next-to-leading-order (NLO) calculation. In the second part of this thesis inclusive differential neutral pion cross-sections in photon photon collisons are measured. This measurement is an important test of QCD. In addition this process is the main background for prompt photons.

  16. Structure of the neutral pion and its electromagnetic transition form factor

    Science.gov (United States)

    Raya, Khépani; Chang, Lei; Bashir, Adnan; Cobos-Martinez, J. Javier; Gutiérrez-Guerrero, L. Xiomara; Roberts, Craig D.; Tandy, Peter C.

    2016-04-01

    The γ*γ →π0 transition form factor, G (Q2), is computed on the entire domain of spacelike momenta using a continuum approach to the two valence body bound-state problem in relativistic quantum field theory: the result agrees with data obtained by the CELLO, CLEO, and Belle Collaborations. The analysis unifies this prediction with that of the pion's valence-quark parton distribution amplitude (PDA) and elastic electromagnetic form factor and demonstrates, too, that a fully self-consistent treatment can readily connect a pion PDA that is a broad, concave function at the hadronic scale with the perturbative QCD prediction for the transition form factor in the hard photon limit. The normalization of that limit is set by the scale of dynamical chiral symmetry breaking, which is a crucial feature of the Standard Model. Understanding of the latter will thus remain incomplete until definitive transition form factor data are available on Q2>10 GeV2 .

  17. Structure of the neutral pion and its electromagnetic transition form factor

    Energy Technology Data Exchange (ETDEWEB)

    Raya, Khépani; Chang, Lei; Bashir, Adnan; Cobos-Martinez, J. Javier; Gutiérrez-Guerrero, L. Xiomara; Roberts, Craig D.; Tandy, Peter C.

    2016-04-01

    The gamma*gamma -> pi(0) transition formfactor, G(Q(2)), is computed on the entire domain of spacelikemomenta using a continuum approach to the two valence body bound-state problem in relativistic quantum field theory: the result agrees with data obtained by the CELLO, CLEO, and Belle Collaborations. The analysis unifies this prediction with that of the pion's valence-quark parton distribution amplitude (PDA) and elastic electromagnetic form factor and demonstrates, too, that a fully self-consistent treatment can readily connect a pion PDA that is a broad, concave function at the hadronic scale with the perturbative QCD prediction for the transition form factor in the hard photon limit. The normalization of that limit is set by the scale of dynamical chiral symmetry breaking, which is a crucial feature of the Standard Model. Understanding of the latter will thus remain incomplete until definitive transition form factor data are available on Q(2) > 10 GeV2.

  18. Double Photoproduction of Neutral Pions on a Proton and a Deuteron

    Science.gov (United States)

    Dusaev, R. R.; Egorov, M. V.

    2017-05-01

    Total cross sections of electromagnetic π0π0 formation processes on a proton and a deuteron in the photon energy range from threshold to E γ ≤ 2 GeV are calculated. Construction of the single-particle photoproduction operator is based on a calculation of Born and resonance contributions calculated in the tree approximation. The main parameters of the nucleon resonances were found from the Particle Data Group (PDG) compilation. A satisfactory description of the p(γ, π0π0) p cross section was achieved assuming a leading role for the pion rescattering process π+π- → π0π0, whose contribution amounted to more than 1 μb in the vicinity of the D 13(1520) resonance.

  19. Double-polarization observable G in neutral-pion photoproduction off the proton

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, A.; Lang, M.; Afzal, F.; Beck, R.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hannappel, J.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Klassen, P.; Klempt, E.; Koop, K.; Kube, M.; Mahlberg, P.; Mueller, J.; Muellers, J.; Piontek, D.; Schmidt, C.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Winnebeck, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Eberhardt, H.; Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Frommberger, F.; Goertz, S.; Hammann, D.; Hillert, W.; Jude, T.; Kammer, S.; Kleber, V.; Klein, F.; Reeve, S.; Runkel, S.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Anisovich, A.V.; Bayadilov, D.; Nikonov, V.; Sarantsev, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bichow, M.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany); Brinkmann, K.T.; Gutz, E. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen und Kernphysik, Bonn (Germany); Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Dieterle, M.; Keshelashvili, I.; Krusche, B.; Witthauer, L. [Universitaet Basel, Institut fuer Physik, Basel (Switzerland); Friedrich, S.; Makonyi, K.; Metag, V.; Nanova, M. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Gridnev, A.; Lopatin, I. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Wilson, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Florida State University, Department of Physics, Tallahassee, FL (United States); Collaboration: The CBELSA/TAPS Collaboration

    2017-01-15

    This paper reports on a measurement of the double-polarization observable G in π{sup 0} photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable G is determined from reactions of linearly polarized photons with longitudinally polarized protons. The polarized photons are produced by bremsstrahlung off a diamond radiator of well-defined orientation. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for G are compared to predictions by the Bonn-Gatchina (BnGa), Juelich-Bonn (JueBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed. (orig.)

  20. Charge Symmetry Breaking In Neutron Proton Scattering To Deuteron And Neutral Pion Close To Threshold

    CERN Document Server

    Reitzner, S D

    2001-01-01

    The charge symmetry breaking (CSB) experiment using the CHARGEX facility and the SASP magnetic spectrometer at TRIUMF has measured the forward-backward scattering asymmetry (Afb) for np→dπ 0 at a neutron beam energy of 279.5 MeV. This reaction is sensitive to contributions not present in elastic scattering and therefore will complement previous measurements of CSB. Contributions to CSB in np→dπ 0 are predicted to be an order of magnitude greater than those found for elastic scattering. These contributions, which include η − π 0 and η′ − π0 mixing and the u - d quark mass difference in pion- nucleon scattering, are predicted to give values for Afb that range from (−35 to +60) × 10−4. A fb can be non-zero only if charge-symmetry is violated. Due to the nature of the observable and the realities of the experiment, Afb is obtained from a χ2 minimization procedure which compares data w...

  1. Neutral pion production at midrapidity in pp and Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Abelev, Betty Bezverkhny; Adamova, Dagmar; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agostinelli, Andrea; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Nazeer; Ahmed, Ijaz; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont Moreno, Ernesto; Belmont Iii, Ronald John; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Berger, Martin Emanuel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Bogolyubskiy, Mikhail; Boehmer, Felix Valentin; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile Ioan; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dainese, Andrea; Dang, Ruina; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; Delagrange, Hugues; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; De Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Di Bari, Domenico; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dorheim, Sverre; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutt Mazumder, Abhee Kanti; Hilden, Timo Eero; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erdal, Hege Austrheim; Eschweiler, Dominic; Espagnon, Bruno; Esposito, Marco; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigory; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floratos, Emmanouil; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gumbo, Mervyn; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Khan, Kamal; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hippolyte, Boris; Hladky, Jan; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Innocenti, Gian Michele; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Jacholkowski, Adam Wlodzimierz; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kadyshevskiy, Vladimir; Kalcher, Sebastian; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Konevskikh, Artem; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; La Pointe, Sarah Louise; La Rocca, Paola; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leoncino, Marco; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Lohner, Daniel; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Luzzi, Cinzia; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martin Blanco, Javier; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Okatan, Ali; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Sahoo, Pragati; Pachmayer, Yvonne Chiara; Pachr, Milos; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares Vales, Carlos; Pal, Susanta Kumar; Palmeri, Armando; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Patalakha, Dmitry; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Pohjoisaho, Esko Heikki Oskari; Polishchuk, Boris; Poljak, Nikola; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Rauf, Aamer Wali; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Sharma, Rohni; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sanchez Rodriguez, Fernando Javier; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Segato, Gianfranco; Seger, Janet Elizabeth; Sekiguchi, Yuko; Selyuzhenkov, Ilya; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wagner, Vladimir; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yang, Shiming; Yano, Satoshi; Yasnopolskiy, Stanislav; Yi, Jungyu; Yin, Zhongbao; Yoo, In-Kwon; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zaman, Ali; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zyzak, Maksym

    2014-10-16

    Invariant yields of neutral pions at midrapidity in the transverse momentum range $0.6 < p_{T} < 12$ GeV/c measured in Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV are presented for six centrality classes. The pp reference spectrum was measured in the range $0.4 < p_{T} < 10$ GeV/c at the same center-of-mass energy. The nuclear modification factor, $R_{AA}$, shows a suppression of neutral pions in central Pb-Pb collisions by a factor of up to about $8-10$ for $5 \\lesssim p_{T} \\lesssim 7$ GeV/c. The presented measurements are compared with results at lower center-of-mass energies and with theoretical calculations.

  2. BRANCHING FRACTION AND TIME-DEPENDENT CP ASYMMETRY IN NEUTRAL B DECAYS TO PSI AND A NEUTRAL PION

    Energy Technology Data Exchange (ETDEWEB)

    Soha, Aron L

    2003-05-23

    The invariance of physical laws under the combination of exchange of particles with antiparticles (charge conjugation, C) and reversal of coordinates (parity, P) is called CP symmetry. The violation of CP symmetry was first discovered in 1964 in the neutral kaon system, and is in general one of the great puzzles of particle physics. The recent observation of CP violation in the B meson system has been a simultaneous success for model predictions and experiment. The opportunity now exists to probe details of the underlying mechanisms. This thesis presents measurements of the branching fraction and time-dependent CP-violating asymmetry in neutral B decays to J/{psi}{pi}{sup 0}. The decay amplitude for this channel features both tree and penguin diagram contributions, the interference of which can yield a result for the asymmetry differing from that found in the ''golden mode'' B{sup 0} {yields} J/{psi} K{sub s}{sup 0}. Using the measured branching fraction and CP asymmetry, constraints are placed on the ratio of penguin to tree amplitudes in B{sup 0} {yields} J/{psi}{pi}{sup 0}. In addition, the impact on the CP asymmetry measurement in B{sup 0} {yields} J/{psi} K{sub s}{sup 0} is discussed. The results are presented for e{sup +}e{sup -} annihilation data collected with the BABAR detector on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy B Factory at SLAC. The measurement of the branching fraction, based on about 23 million B{bar B} pairs collected between October 1999 and October 2000, yields BF(B{sup 0} {yields} J/{psi}{pi}{sup 0}) = (2.0 {+-} 0.6 (stat) {+-} 0.2(syst)) x 10{sup -5}. With about 88 million B{bar B} pairs collected during the years 1999-2002, our results for the coefficients of the cosine and sine terms of the CP asymmetry are C{sub J/{psi}{pi}{sup 0}} = 0.38 {+-} 0.41 (stat) {+-} 0.09 (syst) and S{sub J/{psi}{pi}{sup 0}} = 0.05 {+-} 0.49 (stat) {+-} 0.16 (syst).

  3. A Measurement Of The Neutrino Neutral Current Pion Cross Section At Miniboone

    CERN Document Server

    Raaf, Jennifer L

    2005-01-01

    The MiniBooNE neutrino beam and detector at Fermilab are used to study the production of neutral current π0 events. The cross sections for neutrino interactions with mineral oil (CH2) are reported for resonantly produced and coherently produced single π0 events. We measure a resonant single π0 cross section of σ(ν μ N → νμ N π0) = (0.0129±0.0011 (stat.)±0.0043 (syst.)) × 10-36 cm2/CH 2 at a mean neutrino energy of 1.26 GeV. We measure a coherent single π 0 cross section of σ(νμ A → νμ A π0) = (0.00077±0.00016 (stat.)±0.00036 (cyst.)) × 10-36 cm2/CH 2 at mean neutrino energy 1.12 GeV.

  4. Nuclear Modification of Neutral Pion Production at Low x in √s=200 GeV d+Au and p+p Collisions

    Science.gov (United States)

    Sedgwick, Kenneth Blair

    Nuclear modification factors quantify suppression in particle production due to nuclear effects. They are defined as a ratio of invariant yields, with a numerator derived from a given species of nuclear collision and a denominator derived from a hypothetically equivalent ensemble of independent proton-proton collisions. At large momentum transfer Q 2 and low momentum fraction x, the neutral pion nuclear modification factor Rd+Au for d+Au collisions is useful for investigating initial state gluon saturation. The large initial state gluon multiplicity of the Au nucleus causes saturation effects to occur at lower energies in d+Au collisions, as compared to p+p collisions, resulting in a relative suppression. Measuring the relative suppression R d+Au can therefore test the validity of competing models describing saturation, including the framework of a color glass condensate (CGC). Measurements at low x are of particular interest because in this region linear pQCD evolution equations begin to break down. The Froissart theorem places a robust theoretical upper limit on the behavior of hadronic cross sections: a cross section can increase at most like ln2 E. Equivalently, an hadronic structure function can increase at most like ln2(1/x). Adherence to this theorem is necessary to preserve S-matrix unitarity; no physical system should exhibit behavior to the contrary. However linear evolution equations, which dictate structure function behavior, predict an unchecked growth of low-x gluons, in violation of the theorem. For this reason, it is expected that gluon saturation, via non-linear evolution, will take place at low x to steer the gluon distribution function back within the limitations of the Froissart bound. Greater suppression is expected at lower Q2; however, at low x, regions of high Q 2 are more difficult to access experimentally. Pushing out to higher Q2 is important for discriminating between competing theoretical models. In practice, regions of low x and high Q

  5. Improving the performance of the H→ττ analysis by enhancing reconstruction and identification of neutral pions in tau lepton decays with the CMS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cherepanov, Vladimir; Fluegge, Guenter; Kargoll, Bastian; Lohmann, Wolfgang; Nehrkorn, Alexander; Nugent, Ian M.; Pistone, Claudia; Stahl, Achim; Zotz, Alexander [III. Physikalisches Institut B, RWTH Aachen University, D-52056 Aachen (Germany)

    2016-07-01

    The most promising channel to measure the fermionic couplings of the recently discovered Higgs boson is the decay into two tau leptons. While the decay rate into taus is much smaller than that into b quarks, considerably less background is expected. The largest reducible backgrounds in a search for a Higgs boson decaying into tau leptons originate from multijet and W+jets production where hadronic jets are misidentified as tau leptons. Improving the reconstruction and identification of neutral pions would not only increase the purity of reconstructed decay modes of the tau and reduce migration effects but might also help to distinguish tau jets from hadronic jets, thereby suppressing background.

  6. Transverse momentum distribution and nuclear modification factor of forward neutral pion in proton–lead collisions at $\\sqrt{s_{NN}}$= 5.02 TeV

    CERN Document Server

    Adriani, O; Bonechi, L; Bongi, M; Castellini, G; D’Alessandro, R; Del Prete, M; Haguenauer, M; Itow, Y; Kasahara, K; Kawade, K; Makino, Y; Masuda, K; Matsubayashi, E; Menjo, H; Mitsuka, G; Muraki, Y; Papini, P; Perrot, A-L; Pfeiffer, D; Ricciarini, S; Sako, T; Sakurai, N; Suzuki, T; Tamura, T; Tiberio, A; Torii, S; Tricomi, A; Turner, W C

    2014-01-01

    The transverse momentum ($p_\\text{T}$) distribution for inclusive neutral pions in the very forward rapidity region has been measured, with the Large Hadron Collider forward detector (LHCf), in proton--lead collisions at nucleon-nucleon center-of-mass energies of $\\sqrt{s_{NN}} = 5.02$TeV at the LHC. The $p_\\text{T}$ spectra obtained in the rapidity range $-11.0 < y_\\text{lab} < -8.9$ and $0 < p_\\text{T} < 0.6$GeV (in the detector reference frame) show a strong suppression of the production of neutral pions after taking into account ultra-peripheral collisions. This leads to a nuclear modification factor value, relative to the interpolated $p_\\text{T}$ spectra in proton-proton collisions at $\\sqrt{s} = 5.02$TeV, of about 0.1--0.4. This value is compared with the predictions of several hadronic interaction Monte Carlo simulations.

  7. Jet-like correlations with neutral pion triggers in pp and central Pb-Pb collisions at 2.76 TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Moreno, Ernesto; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Bonora, Matthias; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botta, Elena; Bourjau, Christian; Braun-munzinger, Peter; Bregant, Marco; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buhler, Paul; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crkovska, Jana; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Deisting, Alexander; Deloff, Andrzej; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Duggal, Ashpreet Kaur; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erhardt, Filip; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eulisse, Giulio; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-solis, Edmundo Javier; Garg, Kunal; Garg, Prakhar; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; Germain, Marie; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Sanchez Gonzalez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Grachov, Oleg Anatolievich; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Grelli, Alessandro; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Gronefeld, Julius Maximilian; Grosse-oetringhaus, Jan Fiete; Grosso, Raffaele; Gruber, Lukas; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Bautista Guzman, Irais; Haake, Rudiger; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Incani, Elisa; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Khuntia, Arvind; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minjung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; 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    2016-12-10

    We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta $8 3~\\mathrm{GeV}/c$, while with decreasing momenta an enhancement develops reaching about $5$ at low $p_{\\mathrm{T}}^{\\rm assoc}$. On the near side, an enhancement of $I_{\\mathrm{AA}}$ between $1.2$ at the highest to $1.8$ at the lowest $p_{\\mathrm{T}}^{\\rm assoc}$ is observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high $p_{\\mathrm{T}}^{\\rm assoc}$. Only AMPT captures the enhancement at low $p_{\\mathrm{T}}^{\\rm assoc}$, both on the near and away side. However, it also underpredicts $I_{\\mathrm{AA}}$ above $5$ GeV/$c$, in particular on the near-side.

  8. Jet-like correlations with neutral pion triggers in pp and central Pb–Pb collisions at 2.76 TeV

    Directory of Open Access Journals (Sweden)

    J. Adam

    2016-12-01

    Full Text Available We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta 83 GeV/c, while with decreasing momenta an enhancement develops reaching about 5 at low pTassoc. On the near side, an enhancement of IAA between 1.2 at the highest to 1.8 at the lowest pTassoc is observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high pTassoc. Only AMPT captures the enhancement at low pTassoc, both on the near and away side. However, it also underpredicts IAA above 5 GeV/c, in particular on the near-side.

  9. Transverse mass distributions of neutral pions from 208Pb-induced reactions at 158 A GeV

    NARCIS (Netherlands)

    Aggarwal, M.M.; Agnihotri, A.; Ahammed, Z.A.; Angelis, A.L.S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Barlag, C.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bock, R.; Bohne, E.-M.; Böröcz, Z.K.; Bucher, D.; Buijs, A.; Büsching, H.; Carlén, L.; Chalyshev, V.; Chattopadhyay, S.; Cherbatchev, R.; Chujo, T.; Claussen, A.; Das, A.C.; Decowski, M.P.; Delagrange, H.; Djordjadze, V.; Donni, P.; Doubovik, I.; Dubey, A.K.; Dutt, S.; Dutta Majumdar, M.R.; El Chenawi, K.; Eliseev, S.; Enosawa, K.; Foka, P.; Fokin, S.; Ganti, M.S.; Garpmann, S.; Gavrishchuk, O.; Geurts, F.; Ghosh, T.K.; Glasow, R.; Gupta, S.K.; Guskov, B.; Gustafsson, H.-A.; Gutbrod, H.H.; Higuchi, R.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Kampert, K.-H.; Karadjev, K.; Karpio, K.; Kato, S.; Kees, S.; Klein-Bösing, C.; Knoche, S.; Kolb, B.; Kosarev, I.; Koutcheryaev, I.; Krümpel, T.; Kugler, A.; Kulinich, P.; Kurata, M.; Kurita, K.; Kuzmin, N.; Langbein, I.; Bevedev, A.; Lee, Y.Y.; Löhner, H.; Luquin, L.; Mahapatra, D.P.; Manko, V.; Martin, M.; Martinez, G.; Maximov, A.; Mgebrichvili, G.; Miake, Y.; Mir, Md.F.; Mishra, G.C.; Mitamoto, Y.; Mohanti, B.; Mora, M.-J.; Morrison, D.; Mukhopadhyay, D.S.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Neumaier, S.

    Results on transverse mass spectra of neutral pious measured at central rapidity are presented for impact parameter selected 158-A GeV Pb + Pb-1 and Pb + Nb collisions. The distributions cover the range 0.5 GeV/c(2) less than or equal to MT - Mo less than or equal to 4 GeV/c(2). The change of the

  10. Neutral pion and $\\eta$ meson production in p-Pb collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV

    CERN Document Server

    Acharya, Shreyasi; The ALICE collaboration; Adolfsson, Jonatan; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Al-turany, Mohammad; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Ali, Yasir; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altenkamper, Lucas; Altsybeev, Igor; Andrei, Cristian; Andreou, Dimitra; Andrews, Harry Arthur; Andronic, Anton; Angeletti, Massimo; Anguelov, Venelin; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Apadula, Nicole; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; 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Blau, Dmitry; Blume, Christoph; Boca, Gianluigi; Bock, Friederike; Bogdanov, Alexey; Boldizsar, Laszlo; Bombara, Marek; Bonomi, Germano; Bonora, Matthias; Borel, Herve; Borissov, Alexander; Borri, Marcello; Botta, Elena; Bourjau, Christian; Bratrud, Lars; Braun-munzinger, Peter; Bregant, Marco; Broker, Theo Alexander; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buhler, Paul; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Soto Camacho, Rabi; Camerini, Paolo; Capon, Aaron Allan; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Chandra, Sinjini; Chang, Beomsu; Chang, Wan; Chapeland, Sylvain; Chartier, Marielle; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Chowdhury, Tasnuva; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Concas, Matteo; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Costanza, Susanna; Crkovska, Jana; Crochet, Philippe; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Franz Degenhardt, Hermann; Deisting, Alexander; Deloff, Andrzej; Delsanto, Silvia; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Arteche Diaz, Raul; Dietel, Thomas; Dillenseger, Pascal; Ding, Yanchun; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Van Doremalen, Lennart Vincent; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dudi, Sandeep; Duggal, Ashpreet Kaur; Dukhishyam, Mallick; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erhardt, Filip; Espagnon, Bruno; Eulisse, Giulio; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Fabbietti, Laura; Faggin, Mattia; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Fernandez Tellez, Arturo; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Ganoti, Paraskevi; Garabatos Cuadrado, Jose; Garcia-solis, Edmundo Javier; Garg, Kunal; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; De Leone Gay, Maria Beatriz; Germain, Marie; Ghosh, Jhuma; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-dziadus, Ewa; Glassel, Peter; 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Wenzel, Sandro Christian; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Willems, Guido Alexander; Williams, Crispin; Willsher, Emily; Windelband, Bernd Stefan; Witt, William Edward; Xu, Ran; Yalcin, Serpil; Yamakawa, Kosei; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-kwon; Yoon, Jin Hee; Yun, Eungyu; Yurchenko, Volodymyr; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correa Zanoli, Henrique Jose; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Ya; Zichichi, Antonino; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zmeskal, Johann; Zou, Shuguang

    2018-01-01

    Neutral pion and $\\eta$ meson invariant differential yields were measured in non-single diffractive p-Pb collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV with the ALICE experiment at the CERN LHC. The analysis combines results from three complementary photon measurements, utilizing the PHOS and EMCal calorimeters and the Photon Conversion Method. The invariant differential yields of $\\pi^0$ and $\\eta$ meson inclusive production are measured near mid-rapidity in a broad transverse momentum range of $0.34$ GeV/$c$ at $0.483\\pm0.015{\\rm {(stat.)}}\\pm 0.015 {\\rm{(syst.)}}$. A deviation from $m_{\\rm T}$ scaling is observed for $p_{\\rm T}<2$ GeV/$c$. The measured $\\eta/\\pi^0$ ratio is consistent with previous measurements from pA and pp collisions over the full $p_{\\rm T}$ range. The measured $\\eta/\\pi^0$ ratio at high $p_{\\rm T}$ also agrees within uncertainties with measurements from AA collisions. The $\\pi^0$ and $\\eta$ yields in p-Pb relative to the scaled pp interpolated reference, $R_{\\rm pPb}$, are present...

  11. Jet-like correlations with direct-photon and neutral-pion triggers at sNN=200 GeV

    Directory of Open Access Journals (Sweden)

    L. Adamczyk

    2016-09-01

    Full Text Available Azimuthal correlations of charged hadrons with direct-photon (γdir and neutral-pion (π0 trigger particles are analyzed in central Au+Au and minimum-bias p+p collisions at sNN=200 GeV in the STAR experiment. The charged-hadron per-trigger yields at mid-rapidity from central Au+Au collisions are compared with p+p collisions to quantify the suppression in Au+Au collisions. The suppression of the away-side associated-particle yields per γdir trigger is independent of the transverse momentum of the trigger particle (pTtrig, whereas the suppression is smaller at low transverse momentum of the associated charged hadrons (pTassoc. Within uncertainty, similar levels of suppression are observed for γdir and π0 triggers as a function of zT (≡pTassoc/pTtrig. The results are compared with energy-loss-inspired theoretical model predictions. Our studies support previous conclusions that the lost energy reappears predominantly at low transverse momentum, regardless of the trigger energy.

  12. Measurement of CP Asymmetries and Branching Fractions in Neutral B Meson Decays to Charged Pions and Kaons with the BABAR Detector

    Energy Technology Data Exchange (ETDEWEB)

    Farbin, A.

    2005-02-10

    This dissertation presents a measurement of CP asymmetries and branching fractions for neutral B meson decays to two-body final states of charged pions and kaons. The results are obtained from a data sample of about 88 million {Upsilon}(4S) {yields} B{bar B} decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B factory located at the Stanford Linear Accelerator Center. A fit to kinematic, topological, and particle identification information measures the charge-averaged branching fractions {Beta}(B{sup 0} {yields} {pi}{sup +}{pi}{sup -}) = (4.7 {+-} 0.6 {+-} 0.2) x 10{sup -6} and {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}) = (17.9 {+-} 0.9 {+-} 0.7) x 10{sup -6}; the 90% confidence level upper limit {Beta}(B{sup 0} {yields} K{sup +}K{sup -}) < 0.6 x 10{sup -6}; and the direct CP-violating charge asymmetry {Alpha}{sub K{pi}} = -0.102 {+-} 0.050 {+-} 0.016 [-0.188, -0.016], where the first uncertainties are statistical and the second are systematic and the ranges in square brackets indicate the 90% confidence interval. A fit which adds decay time and b-flavor tagging information measures the CP-violating parameters for B{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays S{sub {pi}{pi}} = 0.02 {+-} 0.34 {+-} 0.05 [-0.54, +0.58] and C{sub {pi}{pi}} = -0.30 {+-} 0.25 {+-} 0.04 [-0.72, +0.12].

  13. Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance

    Energy Technology Data Exchange (ETDEWEB)

    James Kelly; et. Al.

    2005-09-01

    We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q{sup 2} = 1.0 (GeV/c){sup 2} in 10 bins of W across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near 1.232 GeV, but variations among models is large for response functions governed by imaginary parts and for both increases rapidly with W. We performed a nearly model-independent multipole analysis that adjusts complex multipoles with high partial waves constrained by baseline models. Parabolic fits to the W dependence of the multipole analysis around the Delta mass gives values for SMR = (-6.61 +/- 0.18)% and EMR = (-2.87 +/- 0.19)% that are distinctly larger than those from Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+) = (+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe. Finally, using a unitary isobar model (UIM), we find that excitation of the Roper resonance is dominantly longitudinal with S1/2 = (0.05 +/- 0.01) GeV{sup (-1/2)} at Q{sup 2}=1. The ReS0+ and ReE0+ multipoles favor pseudovector coupling over pseudoscalar coupling or a recently proposed mixed-coupling scheme, but the UIM does not reproduce the imaginary parts of 0+ multipoles well.

  14. Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at root s=200 GeV

    Czech Academy of Sciences Publication Activity Database

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C.; Aparin, A. A.; Arkhipkin, D.; Barnovská, Zuzana; Bielčík, J.; Bielčíková, Jana; Chaloupka, P.; Pachr, M.; Rusňák, Jan; Šumbera, Michal; Tlustý, David; Vértési, Robert

    2014-01-01

    Roč. 89, č. 1 (2014), 012001 ISSN 1550-7998 R&D Projects: GA ČR GA13-20841S Institutional support: RVO:61389005 Keywords : pions production * transverse momentum * STAR Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.643, year: 2014

  15. Neutral pion electroproduction and virtual Compton scattering on proton with four-momentum transfer squared Q{sup 2} = 1 GeV{sup 2}. Measurement of cross-sections and of generalized polarizabilities; Electroproduction de photons et de pions sur le proton au quadrimoment de transfert Q{sup 2} = 1.0 GeV{sup 2}. Mesure des sections efficaces et extraction des polarisabilites generalisees

    Energy Technology Data Exchange (ETDEWEB)

    Laveissiere, G

    2001-11-01

    In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focussed on the VCS experiment performed at Jefferson Lab in 1998. The 4 GeV electron beam is scattered off a cryogenic hydrogen target, and the scattered electron and recoiled proton are detected in coincidence in the twin hall A spectrometers. The photon (pion) is reconstructed using a missing particle technique. The data analysis allowed to extract the cross sections relative to both process at four-momentum transfer squared Q{sup 2} = 1 GeV{sup 2}. The VCS cross section has been extracted for the first time in the proton resonance region (W between 1.O and 2.0 GeV) through the photon electroproduction reaction. Around the pion-production threshold up to the Delta(1232) resonance region, these results lead to the measurement of the generalized polarizabilities, that describe the proton structure in the same way as the elastic form factors. Moreover, the neutral pion electroproduction cross section measurement in the resonance region has brought new constraints on the existing phenomenological models. (author)

  16. Measurement of the Nuclear Dependence of Direct Photon and Neutral Meson Production at High Transverse Momentum by Negative 515-GeV/c Pions Incident on Beryllium and Copper Targets

    Energy Technology Data Exchange (ETDEWEB)

    Sorrell, Lee Ronald [Michigan State Univ., East Lansing, MI (United States)

    1995-01-01

    The nuclear dependence of inclusive direct photon production and inclusive neutral meson production by a 515 GeV/c $\\pi^-$ beam has been measured using data collected by the E706 experiment during the 19.90 fixed, target run at the Fermi National Accelerator Laboratory. The experiment utilized a finely segmented liquid argon calorimeter and a high precision charged particle spectrometer to make precision measurements of inclusive direct photon, neutral pion, and $\\eta$ production in the rapidity interval from -0.75 < $y$ < 0.75. The $\\pi^0$ data is reported for the $P_T$ range from 0.6 GeV /c to 12 GeV /c, while the $\\eta$ data is reported for the range from 3.5 GeV /c to 7.0 GeV /c. The direct photon nuclear dependence results are reported for the range from approxlmately 4.0 GeV/c to 8.5 GeV/c. The data from the beryllium and copper targets have been fit using the parameterization $\\sigma_A$ = $\\sigma_0$ x $A^{\\alpha}$. The neutral meson results are in good agreement with previous charged meson results. The direct photon results are consistent with no anomalous enhancement.

  17. The pion: an enigma within the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Tanja; Roberts, Craig D.

    2016-05-27

    Almost 50 years after the discovery of gluons & quarks, we are only just beginning to understand how QCD builds the basic bricks for nuclei: neutrons, protons, and the pions that bind them. QCD is characterised by two emergent phenomena: confinement & dynamical chiral symmetry breaking (DCSB). They are expressed with great force in the character of the pion. In turn, pion properties suggest that confinement & DCSB are closely connected. As both a Nambu-Goldstone boson and a quark-antiquark bound-state, the pion is unique in Nature. Developing an understanding of its properties is thus critical to revealing basic features of the Standard Model. We describe experimental progress in this direction, made using electromagnetic probes, highlighting both improvements in the precision of charged-pion form factor data, achieved in the past decade, and new results on the neutral-pion transition form factor. Both challenge existing notions of pion structure. We also provide a theoretical context for these empirical advances, first explaining how DCSB works to guarantee that the pion is unnaturally light; but also, nevertheless, ensures the pion is key to revealing the mechanisms that generate nearly all the mass of hadrons. Our discussion unifies the charged-pion elastic and neutral-pion transition form factors, and the pion's twist-2 parton distribution amplitude. It also indicates how studies of the charged-kaon form factor can provide significant contributions. Importantly, recent predictions for the large-$Q^2$ behaviour of the pion form factor can be tested by experiments planned at JLab 12. Those experiments will extend precise charged-pion form factor data to momenta that can potentially serve in validating factorisation theorems in QCD, exposing the transition between the nonperturbative and perturbative domains, and thereby reaching a goal that has long driven hadro-particle physics.

  18. Multi-pion production

    Energy Technology Data Exchange (ETDEWEB)

    Beavis, D.; Fung, S.Y.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T.; VanDalen, G.; Vient, M.

    1984-01-01

    Preliminary analysis of pion production in 1.2 GeV/nucleon Kr-RbBr collisions is presented. The negative pion multiplicity is consistent with a convolution of Poisson distributions and a freeze-out density between 1/3 and 1/2 normal nuclear density is extracted. Global negative pion kinematic variables are used to search for possible structure in the multi-pion emission. No evidence for structured emission or conservation constraints is found. Pion interferometry analysis gives a source radius of 5.4 +- 1.2 Fermi and a freeze-out density of .3 +- .2 times normal nuclear density. 10 refs., 5 figs.

  19. Soft Pion Processes

    Science.gov (United States)

    Nambu, Y.

    1968-01-01

    My talk is concerned with a review, not necessarily of the latest theoretical developments, but rather of an old idea which has contributed to recent theoretical activities. By soft pion processes I mean processes in which low energy pions are emitted or absorbed or scattered, just as we use the word soft photon in a similar context. Speaking more quantitatively, we may call a pion soft if its energy is small compared to a natural scale in the reaction. This scale is determined by the particular dynamics of pion interaction, and one may roughly say that a pion is soft if its energy is small compared to the energies of the other individual particles that participate in the reaction. It is important to note at this point that pion is by far the lightest member of all the hadrons, and much of the success of the soft pion formulas depends on this fact.

  20. Study of neutral pions in Pb-Pb collisions at $\\sqrt{^{s}}NN$= 2.76 TeV with the PHOS detector at ALICE

    CERN Document Server

    Sekihata, Daiki

    A state of decon ned quarks and gluons, called quark-gluon plasma (QGP), is created in high-energy heavy-ion collisions. The ALICE experiment is one of the heavy-ion collider experiments at the LHC to investigate such the new state of mat- ter. Neutral mesons such as 0 that decays into two photons are suitable to study parton energy-loss in the QGP, since they can be identi ed by a ne-segmented elec- tromagnetic calorimeter in a wide p T range. It is quite competitive with respect to other particle identi cation methods. The energy-loss results in a suppression of hadrons yields quanti ed with a nuclear modi cation factor R AA de ned as hadron yields in A-A collisions with respect to those in p-p collisions. Partons created by a hard scattering interacts with the medium and lose energy. This phenomenon modi es hadron yields at a high p T and can be powerful probe to disentangle mechanism of the energy-loss in the QGP.

  1. Experimental studies of pion-nucleus interactions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

  2. Pion transition form factor in the constituent quark model

    Science.gov (United States)

    Dorokhov, A. E.; Kuraev, E. A.

    2013-07-01

    We calculate the transition form factor of the neutral pion where one photon is virtual and another photon is real in the model where the light constituent quark mass and the quark-pion vertex are taken to be momentum independent. Radiative corrections to the lowest order triangle quark Feynman amplitude are calculated. The resummation of the lowest radiative corrections to the virtual photon vertex is done by applying the Sudakov exponential hypothesis. By using fitting parameters, the quark mass and the strong coupling constant, the results on the pion transition form factor are compared with existing data published by CELLO, CLEO, BABAR, and Belle collaborations.

  3. On the role of secondary pions in spallation targets

    CERN Document Server

    Mancusi, Davide; Colonna, Nicola; Boudard, Alain; Cortés-Giraldo, Miguel Antonio; Cugnon, Joseph; David, Jean-Christophe; Leray, Sylvie; Lerendegui-Marco, Jorge; Massimi, Cristian; Vlachoudis, Vasilis

    2017-01-01

    We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20-GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.

  4. On the role of secondary pions in spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Mancusi, Davide [Paris-Saclay Univ., Gif-sur-Yvette (France). Den-Service d' Etude des Reacteurs et de Mathematiques Appliquees (SERMA); Lo Meo, Sergio [ENEA, Research Centre ' ' Ezio Clementel' ' , Bologna (Italy); INFN, Bologna (Italy); Colonna, Nicola [INFN, Bari (Italy); Boudard, Alain; David, Jean-Christophe; Leray, Sylvie [Paris-Saclay Univ., Gif-sur-Yvette (France). IRFU, CEA; Cortes-Giraldo, Miguel Antonio; Lerendegui-Marco, Jorge [Sevilla Univ. (Spain). Facultad de Fisica; Cugnon, Joseph [Liege Univ. (Belgium). AGO Dept.; Massimi, Cristian [INFN, Bologna (Italy); Bologna Univ. (Italy). Physics and Astronomy Dept.; Vlachoudis, Vasilis [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2017-05-15

    We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the nTOF lead spallation target, irradiated with 20 GeV/c protons, neutral pions are involved in the production of ∝ 90% of the high-energy photons; charged pions participate in ∝ 40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets. (orig.)

  5. Improved measurement of neutral current coherent $\\pi^0$ production on carbon in a few-GeV neutrino beam

    Energy Technology Data Exchange (ETDEWEB)

    Kurimoto, Y.; /KEK, Tsukuba; Alcaraz-Aunion, J.L.; /Barcelona, IFAE; Brice, S.J.; /Fermilab; Bugel, L.; /MIT; Catala-Perez, J.; /Valencia U. /Valencia U., IFIC; Cheng, G.; /Columbia U.; Conrad, J.M.; /MIT; Djurcic, Z.; /Columbia U.; Dore, U.; /INFN, Rome; Finley, D.A.; /Fermilab; Franke, A.J.; /Columbia U. /INFN, Rome

    2010-05-01

    The SciBooNE Collaboration reports a measurement of neutral current coherent neutral pion production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive neutral pion production has been improved by detecting recoil protons from resonant neutral pion production. We measure the ratio of the neutral current coherent neutral pion production to total charged current cross sections to be (1.16 +/- 0.24) x 10-2. The ratio of charged current coherent pion to neutral current coherent pion production is calculated to be 0.14+0.30 -0.28, using our published charged current coherent pion measurement.

  6. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  7. Measurements of tau decays to three pions

    Science.gov (United States)

    Band, H. R.; Camporesi, T.; Chadwick, G. B.; Delfino, M. C.; De Sangro, R.; Ford, W. T.; Gettner, M. W.; Goderre, G. P.; Groom, D. E.; Hurst, R. B.; Johnson, J. R.; Lavine, T. L.; Leedy, R. E.; Maruyama, T.; Messner, R. L.; Moss, L. J.; Muller, F.; Nelson, H. N.; Peruzzi, I.; Piccolo, M.; Prepost, R.; Pyrlik, J.; Qi, N.; Read, A. L.; Ritson, D. M.; Rosenberg, L. J.; Sleeman, J. C.; Smith, J. G.; Venuti, J. P.; Verdini, P. G.; Von Goeler, E.; Weinstein, Roy; Wiser, D. E.; Zdarko, R. W.; MAC Collaboration

    1987-11-01

    We reports the result of a study of a tau decays with three pions in the final state ( τ±→ π±π+π-υτ and τ±→ π±π0π0υτ) from data accumulated with the MAC detector operating at the PEP storage ring. The branching fractions for these modes are measured to be 0.070±0.003±0.007 and, with assumptions discussed in the text, 0.087±0.004±0.011, respectively. Assuming that these final states result from the decay of the a 1 meson, we measure the resonant parameters of the a 1 with the three charged pion sample to be ma1=1166±18±11 MeV and γa1=405±75±25 MeV, and with the one charged plus two neutral pions sample to be ma1=1164±41±23 MeV and γa1=419±108±57 MeV.

  8. Pion Polarizability Status Report (2017)

    OpenAIRE

    Moinester, Murray

    2017-01-01

    The electric ${\\alpha}_{\\pi}$ and magnetic $\\beta_{\\pi}$ charged pion Compton polarizabilities are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD).They are directly linked to the phenomenon of spontaneously broken chiral symmetry within QCD and to the dynamics of the pion-photon interaction.The combination (${\\alpha}_{\\pi}-\\beta_{\\pi}$) was measured by:(1) CERN COMPASS via radiative pion Primakoff scattering (Bremsstrahlung) in the nuclear Coulomb field, ${\\pi...

  9. Pion polarizabilities measurement at COMPASS

    CERN Document Server

    Guskov, Alexey

    2008-01-01

    The electromagnetic structure of pions is probed in $\\pi^{−} + (A,Z)\\rightarrow\\pi^{−} + (A,Z) +\\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric $(\\bar{\\alpha_{\\pi}})$ and the magnetic $(\\bar{\\beta_{\\pi}})$ polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of pointlike pions with the measured cross section. The pion polarizability measurement was performed with $a \\pi^{−}$ beam of 190 GeV. The high beam intensity, the good spectrometer resolution, the high rate capability, the high acceptance and the possibility to use pion and muon beams, unique to the COMPASS experiment, provide the tools to measure precisely the pion polarizabilities in the Primakoff reaction. The preliminary result for pion polarizabilities under the assumption of $\\bar{\\alpha_{\\pi}} + \\bar{\\beta_{\\pi}} =$ 0 is $\\ba...

  10. {rho}{sup 0}-{gamma} mixing in the neutral channel pion form factor F{sub {pi}}{sup (e)}(s) and its role in comparing e{sup +}e{sup -} with {tau} spectral functions

    Energy Technology Data Exchange (ETDEWEB)

    Jegerlehner, Fred [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Szafron, Robert [Uniwersytet Slaski, Katowice (Poland). Inst. Fizyki

    2011-01-15

    We study the effect of {rho}{sup 0}-{gamma} mixing in e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -} and its relevance for the comparison of the square modulus of the pion form-factor vertical stroke F{sub {pi}}{sup (e)}(s) vertical stroke {sup 2}, as measured in e{sup +}e{sup -} annihilation experiments, and vertical stroke F{sub {pi}}{sup ({tau})}(s) vertical stroke {sup 2} the corresponding quantity obtained after accounting for known isospin breaking effects by an isospin rotation from the {tau}-decay spectra. After correcting the {tau} data for the missing {rho}-{gamma} mixing contribution, besides the other known isospin symmetry violating corrections, the {pi}{pi} I=1 part of the hadronic vacuum polarization contribution to the muon g - 2 are fully compatible between {tau} based and e{sup +}e{sup -} based evaluations. {tau} data thus confirm result obtained with e{sup +}e{sup -} data. Our evaluation of the leading order vacuum polarization contribution, based on all e{sup +}e{sup -} data including more recent BaBar and KLOE data, yields a{sub {mu}}{sup had,LO}[e]=690.75(4.72) x 10{sup -10} (e{sup +}e{sup -} based), while including {tau} data we find a{sub {mu}}{sup had,LO}[e, {tau}]=690.96(4.65) x 10{sup -10} (e{sup +}e{sup -} + {tau} based). This backs the {proportional_to}3{sigma} deviation between a{sub {mu}}{sup experiment} and a{sub {mu}}{sup theory}. For the {tau} di-pion branching fraction we find B{sub {pi}}{sub {pi}{sup 0}}{sup CVC} = 25.20 {+-} 0.0.17 {+-} 0.28 from e{sup +}e{sup -}+CVC, while B{sub {pi}}{sub {pi}{sup 0}}0 = 25.34 {+-} 0.0.06 {+-} 0.08 is evaluated directly from the {tau} spectra. (orig.)

  11. Pions in the nuclear medium

    Energy Technology Data Exchange (ETDEWEB)

    Chanfray, G.

    1996-07-01

    We discuss various aspects of pion physics in the nuclear medium. We first study s-wave pion-nucleus interaction in connection with chiral symmetry restoration and quark condensate in the nuclear medium. We then address the question of p-wave pion-nucleus interaction and collective pionic modes in nuclei and draw the consequences for in medium {pi}{pi} correlations especially in the scalar-isoscalar channel. We finally discuss the modification of the rho meson mass spectrum at finite density and/or temperature in connection with relativistic heavy ion collisions. 37 refs.

  12. Pion form factor

    Energy Technology Data Exchange (ETDEWEB)

    Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)

    1994-04-01

    It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.

  13. Charged Pion Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Haiyan Gao, Wei Chen

    2009-12-01

    We extracted the differential cross section for the gn --> pi-p process from a deuterium target using the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (theta c.m.) between 50 deg. and 115 deg. We confirm a previous indication of a broad enhancement around a c.m. energy (sqrt s) of 2.1 GeV at theta c.m. =90 deg. in the scaled differential cross section, s^7 ds/dt and a rapid fall-off in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for theta c.m. from 70 deg. to 10 deg.

  14. Experimental studies of pion-nucleus interactions at intermediate energies. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

  15. Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

    Directory of Open Access Journals (Sweden)

    C. Adolph

    2015-05-01

    Full Text Available Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.

  16. Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised proton

    CERN Document Server

    Adolph, C; Alexeev, M G; Alexeev, G D; Amoroso, A; Andrieux, V; Anosov, V; Austregesilo, A; Badełek, B; Balestra, F; Barth, J; Baum, G; Beck, R; Bedfer, Y; Berlin, A; Bernhard, J; Bicker, K; Bieling, J; Birsa, R; Bisplinghoff, J; Bodlak, M; Boer, M; Bordalo, P; Bradamante, F; Braun, C; Bressan, A; Büchele, M; Burtin, E; Capozza, L; Chiosso, M; Chung, S U; Cicuttin, A; Crespo, M L; Curiel, Q; Dalla Torre, S; Dasgupta, S S; Dasgupta, S; Denisov, O Yu; Donskov, S V; Doshita, N; Duic, V; Dünnweber, W; Dziewiecki, M; Efremov, A; Elia, C; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Finger jr , M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Frolov, V; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S; Geyer, R; Gnesi, I; Gobbo, B; Goertz, S; Gorzellik, M; Grabmüller, S; Grasso, A; Grube, B; Grussenmeyer, T; Guskov, A; Guthörl, T; Haas, F; von Harrach, D; Hahne, D; Hashimoto, R; Heinsius, F H; Herrmann, F; Hinterberger, F; Höppner, Ch; Horikawa, N; d’Hose, N; Huber, S; Ishimoto, S; Ivanov, A; Ivanshin, Yu; Iwata, T; Jahn, R; Jary, V; Jasinski, P; Jörg, P; Joosten, R; Kabuß, E; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Klimaszewski, K; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Kotzinian, A M; Kouznetsov, O; Krämer, M; Kroumchtein, Z V; Kuchinski, N; Kunne, F; Kurek, K; Kurjata, R P; Lednev, A A; Lehmann, A; Levillain, M; Levorato, S; Lichtenstadt, J; Maggiora, A; Magnon, A; Makke, N; Mallot, G K; Marchand, C; Martin, A; Marzec, J; Matousek, J; Matsuda, H; Matsuda, T; Meshcheryakov, G; Meyer, W; Michigami, T; Mikhailov, Yu V; Miyachi, Y; Nagaytsev, A; Nagel, T; Nerling, F; Neubert, S; Neyret, D; Nikolaenko, V I; Novy, J; Nowak, W -D; Nunes, A S; Olshevsky, A G; Orlov, I; Ostrick, M; Panknin, R; Panzieri, D; Parsamyan, B; Paul, S; Peshekhonov, D V; Platchkov, S; Pochodzalla, J; Polyakov, V A; Pretz, J; Quaresma, M; Quintans, C; Ramos, S; Regali, C; Reicherz, G; Rocco, E; Rossiyskaya, N S; Ryabchikov, D I; Rychter, A; Samoylenko, V D; Sandacz, A; Sarkar, S; Savin, I A; Sbrizzai, G; Schiavon, P; Schill, C; Schlüter, T; Schmidt, K; Schmieden, H; Schönning, K; Schopferer, S; Schott, M; Shevchenko, O Yu; Silva, L; Sinha, L; Sirtl, S; Slunecka, M; Sosio, S; Sozzi, F; Srnka, A; Steiger, L; Stolarski, M; Sulc, M; Sulej, R; Suzuki, H; Szabelski, A; Szameitat, T; Sznajder, P; Takekawa, S; ter Wolbeek, J; Tessaro, S; Tessarotto, F; Thibaud, F; Uhl, S; Uman, I; Virius, M; Wang, L; Weisrock, T; Wilfert, M; Windmolders, R; Wollny, H; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziembicki, M; Zink, A

    2015-01-01

    Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.

  17. Shape of Pion Distribution Amplitude

    Energy Technology Data Exchange (ETDEWEB)

    Radyushkin, Anatoly

    2009-11-01

    A scenario is investigated in which the leading-twist pion distribution amplitude $\\varphi_\\pi (x)$ is approximated by the pion decay constant $f_\\pi$ for all essential values of the light-cone fraction $x$. A model for the light-front wave function $\\Psi (x, k_\\perp)$ is proposed that produces such a distribution amplitude and has a rapidly decreasing (exponential for definiteness) dependence on the light-front energy combination $ k_\\perp^2/x(1-x)$. It is shown that this model easily reproduces the fit of recent large-$Q^2$ BaBar data on the photon-pion transition form factor. Some aspects of scenario with flat pion distribution amplitude are discussed.

  18. Light quark fragmentations into pions

    Science.gov (United States)

    Edemskaya, A. K.; Naumov, D. V.; Samoylov, O. B.

    2011-12-01

    We discuss a process of hadronization of light quarks into charged pions in e + e - annihilations and in deep inelastic scatering of charged leptons and neutrino off nucleons. The corresponding semi-inclusive cross-sections of pions production we write in terms of quark fragmentation functions and fracture functions. We suggest a new method of measurements of fragmentation and fracture functions based on analysis of semiinclusive data.

  19. Investigation of pion-nucleus interactions. [295 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Moore, C.F.

    1992-09-01

    This report summarizes the work carried out by personnel from the University of Texas at Austin at the Los Alamos Clinton P. Anderson Meson Physics Facility (LAMPF). The research activities involved experiments done with the Energetic Pion Channel and Spectrometer (EPICS), the Low Energy Pion Channel (LEP), the Pion and Particle Physics Channel (P[sup 3]), the High Resolution Spectrometer (HRS), and planning a new experimental program associated with the new high-resolution Neutral Meson Spectrometer (NMS) at LAMPF. A brief overview of work supported by this grant is given followed by an account of the study of the double giant resonances in pion double charge exchange on [sup 51]V, [sup 115]In, and [sup 197]Au. This report contains a list of published papers and preprints, abstracts, and invited talks. These papers summarize experiments involving participants supported by this grant and indicate the work accomplished by these participants in this program of medium energy nuclear physics research. Lists of the most recent proposals on which we have participation at LAMPF, proposals which have been approved this past year to run as experiments, personnel who have participated in this research program are included. The research cited in this report is, in many cases, the collaborative effort of many groups associated with research at LAMPF.

  20. The pion polarisability and more measurements on chiral dynamics at COMPASS

    CERN Document Server

    Friedrich, Jan

    2016-01-01

    Within the physics program of the COMPASS experiment at CERN pion-photon reactions are measured via the Primakoff effect, referring to processes in which high-energetic pions react with the quasi-real photon field that surrounds the target nuclei. The production of a single hard photon in such a pion scattering at lowest momentum transfer to the nucleus is related to pion Compton scattering. From the measured cross-section shape, the pion polarisability has been determined, a result that has been published meanwhile as a Physical Review Letter [ 1 ]. The COMPASS measurement is in tension with the earlier dedicated measurements, and rather in agreement with the theoretical expectation from chiral perturbation theory. The analysis of a more recent high-statistics data taking is underway. Reactions with neutral and more charged pions in the final state are measured and analyzed as well. At low energy in the pion-photon centre-of-momentum system, these reactions are governed by chiral dynamics and contain informa...

  1. Pion structure from lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Javadi Motaghi, Narjes

    2015-05-12

    In this thesis we use lattice QCD to compute the second Mellin moments of pion generalized parton distributions and pion electromagnetic form factors. For our calculations we are able to analyze a large set of gauge configurations with 2 dynamical flavours using non-perturbatively the improved Wilson-Sheikholeslami-Wohlert fermionic action pion masses ranging down to 151 MeV. By employing improved smearing we were able to suppress excited state contamination. However, our data in the physical quark mass limit show that some excited state contamination remains. We show the non-zero sink momentum is optimal for the computation of the electromagnetic form factors and generalized form factors at finite momenta.

  2. Inclusive and exclusive pion reactions

    Science.gov (United States)

    Collier, Sandra Lee

    1998-12-01

    One inclusive and one exclusive pion reaction are addressed. For the first, a model for pion-induced pion production ( p,2p ) from nuclei is developed with particular interest in the dependence of the 2p invariant mass distribution as a function of the target mass. Data from ( p,2p ) reactions on free nucleons are used to predict modifications in the production cross sections on nuclei due to medium corrections which might arise from a change in the structure of the nucleon in the nucleus. The ( p,2p ) reaction from the nucleon is modeled using the pion pole diagram. The form factor which governs this cross section is modified to model changes of the nucleon structure within the nuclear medium. Another medium effect, the fermi motion of the nucleon with respect to the nucleus, is also considered. It is found that the differential cross section for production from nuclei is sensitive to the changes of the form factor, but the shape of the invariant mass distribution is not. Comparisons are made to recent experimental findings from 208Pb, 40Ca, 12C, and 2H. The elastic scattering of charged pions from the trinucleon system is then examined at a pion kinetic energy of 180 MeV. The motivation for this study is the structure seen in the angular distribution of back-angle scattering for p+-H3e and p--H3 but for neither p-- H3e nor p+-H3 . A double spin flip mechanism is included in an optical model treatment. It is found that the contribution of this term is non- negligible at large angles for p+-H3e and p--H3 , but it does not reproduce the structure seen in the experiment.

  3. Scrutinizing the pion condensed phase

    Energy Technology Data Exchange (ETDEWEB)

    Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)

    2017-02-15

    When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)

  4. Weak pion production from nuclei

    Indian Academy of Sciences (India)

    The pion production processes from nucleons and nuclei at intermediate energies are important tools to study the hadronic structure. The dynamic models of the hadronic structure are used to calculate the various nucleon and transition form factors which are tested by using the experimental data on photo, electro and.

  5. Pauli Principle and Pion Scattering

    Science.gov (United States)

    Bethe, H. A.

    1972-10-01

    It is pointed out that if the Pauli principle is taken into account in the discussion of pion scattering by complex nuclei (as it ought, of course, to be) some rather implausible consequences of some earlier treatments of this problem can be avoided. (auth)

  6. Rare pion and kaon decays

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.

    1984-05-01

    Some rare pion and kaon decays, which provide clues to the generation puzzle, are discussed. The ..pi.. ..-->.. e ..nu../..pi.. ..-->.. ..mu nu.. branching ratio test of universality and the status of searches for K/sup +/ ..-->.. ..pi../sup +/..nu..nu-bar are reviewed.

  7. Rare pion and kaon decays

    Science.gov (United States)

    Bryman, Douglas

    1984-05-01

    Some rare pion and kaon decays, which provide clues to the generation puzzle, are discussed. The π → e ν/π → μν branching ratio test of universality and the status of searches for K+ → π+νν¯ are reviewed.

  8. Weak pion production from nuclei

    Indian Academy of Sciences (India)

    The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the ...

  9. Measurement of the pion polarizabilities at COMPASS

    CERN Document Server

    Guskov, A V

    2006-01-01

    The electromagnetic structure of pions is probed in $\\pi\\gamma$ Compton scattering in inverse kinematics (Primakoff effect) and described by the electric ($\\alpha_{\\pi}$) and magnetic ($\\beta_{\\pi}$) polarizabilities, that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the theoretically predicted (under approximation of unstructured pion) cross section of Primakoff scattering and the measured cross section. The high beam intensity, good spectrometer resolution, the high rate capability, the high acceptance and possibility to use pion and muon beams, that are unique to the COMPASS experiment provide the tools to measure precisely the pion polarizabilities in the $\\pi^{-} + (A,Z)\\rightarrow\\pi^{-} + (A,Z) + \\gamma$ Primakoff reaction. This cross section is related to the cross section of Compton scattering on pion. A precise tracking system, electromagnetic and hadron calorimeters provide good conditions for...

  10. Measurement of the Neutral Pion Electromagnetic Transition Form Factor

    Science.gov (United States)

    Drees, Reena Meijer

    We present the result of a measurement of the pi^0 electromagnetic transition form factor in the time-like region of momentum transfer. From a data sample of roughly 100,000 pi^0 to e^+ e^-gamma decays, observed in the SINDRUM I magnetic spectrometer at the Paul Scherrer Institute (Switzerland), we measure a value of the form factor slope a = 0.02 +/- 0.01 (stat) +/- 0.02 (sys). This measurement is consistent with both the results of the recent measurement by CELLO (DESY) in the space-like region, and with the vector meson dominance prediction of a ~ 0.03.

  11. Resonance Production through the Two Neutral-Pion Channel

    Energy Technology Data Exchange (ETDEWEB)

    Philips, Sasha A. [George Washington Univ., Washington, DC (United States)

    2002-01-30

    We have obtained data for the γp → π0π0 reaction with the CLAS at Jefferson Lab for photon energies 0.4 < Eγ < 1.7 GeV. These data extend previous total-cross-section measurements of the γp → π0π0 channel beyond Eγ = 800 MeV, and show a strong enhancement of resonance production at Eγ ~ 1.1 GeV (Wcms ~ 1.7 GeV). The proton and forward-going π0 were detected in the CLAS, while the backward π0 has been reconstructed from missing mass. An intermediate Δ state can be reconstructed from the proton and the backward π0, which provides information on the sequential decay of the γp → N* → Δ+ π0 → π0 π0 process. The Δ+ π0 intermediate state is a significant part of the cross section at center-of-mass energies of W ~ 1700 MeV and W ~ 1930 MeV. The enhancement at W ~ 1.7 GeV is broad, and coincides with the structure seen in the total cross-section measurement. This is most likely the signature of a nucleon resonance having a mass of 1650-1750 MeV, with strong Δπ and γp couplings. The enhancement at W ~ 1.9 GeV, however, is narrow and therefore is unlikely to arise from resonance production or the interference of a resonance with non-resonant background. The proximity of the enhancement to the pn' threshold (W = 1896 MeV), as well as evidence from other analyses for the presence of a resonance at this mass, suggests a cusp phenomenon. There is also evidence for the γp → (N* → D13(1520) π0) → (p π0) π0 two-step process, that is enhanced at W approx. 1.83 GeV. No resonances have been previously observed at this energy. Finally, for events that did not proceed through the two decay chains mentioned above, there is an enhancement at W approx. 1.7 GeV. This could possibly be the signature of a resonance decaying via the γp → pσ → p(π0 π0) process. If this enhancement arises from the same resonance in the Δπ channel, then its branching fraction would be roughly 1/2 that of the Δπ channel.

  12. Neutral Pion Electroproduction in the Δ Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Villano, Anthony [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2007-11-01

    The electroproduction of baryon resonances at high Q2 is examined. Analysis focuses on the Δ(1232) resonance via exclusive pseudoscalar meson production of π0 particles. Differential cross sections are extracted for exclusive π0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Δ(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Δ region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor G$*\\atop{M}$ is extracted along with the scalar to magnetic dipole ratio C2/M1.

  13. Study of $f_{0}$ decays into four neutral pions

    CERN Document Server

    Abele, A; Amsler, Claude; Baker, C A; Barnett, B M; Batty, C J; Benayoun, M; Bischoff, S; Blüm, H P; Braune, K; Case, T; Credé, V; Crowe, K M; Degener, T F; Doser, Michael; Dünnweber, W; Engelhardt, D; Faessler, M A; Giarritta, P; Haddock, R P; Heinsius, F H; Heinzelmann, M; Herbstrith, A; Hessey, N P; Hidas, P; Holtzhaussen, C; Jamnik, D; Kalinowsky, H; Kammel, P; Kisiel, J; Klempt, E; Koch, H; Kunze, M; Kurilla, U; Lakata, M T; Landua, Rolf; Matthäy, H; Meyer, C A; Meyer-Wildhagen, F; Montanet, Lucien; Ouared, R; Peters, K; Pick, B; Ratajczak, M; Regenfus, C; Röthel, W; Spanier, S M; Stöck, H; Strohbusch, U; Suffert, Martin; Suh, J S; Thoma, U; Tischhäuser, M; Uman, I; Wallis-Plachner, S; Walther, D; Wiedner, U; Wittmack, K

    2001-01-01

    A simultaneous analysis of two different 5 pi final states from pN annihilation at rest is used to study the decays of isoscalar 0/sup ++/ states into 4 pi /sup 0/. The data demand two scalar states, the f/sub 0/(1370) with m=1395+or-40 MeV/c/sup 2/, Gamma =275+or-55 MeV/c /sup 2/ and the f/sub 0/(1500) with mass and width compatible with previous findings. Apart from the dominant scalar intensity, the pi (1300) plays an important role in the 5 pi dynamics. We find a mass of m=1375+or-40 MeV/c/sup 2/ and a width of Gamma =268+or-50 MeV/c /sup 2/ with a dominant decay into rho pi . The ( pi pi )/sub s/ pi - decay of the pi (1300) is less than 15% of its rho pi decay. (33 refs).

  14. Direct СP violation in neutral kaon decays

    Indian Academy of Sciences (India)

    The final result of the NA48 experiment is presented and performed at the CERN SPS neutral kaon beams, on the direct CP violation parameter Re ( ′ / ) , as measured from the decay rates of neutral kaons into two pions. The data collected in the years 1997-2001 yield the evidence for the direct CP violation with Re ...

  15. Dalitz Plot Analysis Of Neutral B-meson Decays To Charged Kaon, Charged Pion, And Neutral Pion Final States

    CERN Document Server

    Yu, Z

    2005-01-01

    This thesis describes a Dalitz plot analysis of B0 → K+π−π 0 decays. The data sample comprises 213 million &Ugr;(4 S) → BB¯ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center in California (SLAGC). Preliminary results are presented for measurements of the inclusive branching fraction, quasi-two-body fractions and CP-violating charge asymmetries for intermediate states including K*(892)+π − and ρ(770)−K +. Observations of B0 decays to the Kπ S-wave intermediate states, K*0 (1430)+π− and K*0 (1430)0π0, are reported. Evidence of the decay B0 → K*(892) 0π0 is seen. We set tipper limits at 90% confidence level on branching fractions of the nonresonant and other less significant intermediate states.

  16. Measurement of inclusive neutral current π0 production on carbon in a few-GeV neutrino beam

    Science.gov (United States)

    Kurimoto, Y.; Alcaraz-Aunion, J. L.; Brice, S. J.; Bugel, L.; Catala-Perez, J.; Cheng, G.; Conrad, J. M.; Djurcic, Z.; Dore, U.; Finley, D. A.; Franke, A. J.; Giganti, C.; Gomez-Cadenas, J. J.; Guzowski, P.; Hanson, A.; Hayato, Y.; Hiraide, K.; Jover-Manas, G.; Karagiorgi, G.; Katori, T.; Kobayashi, Y. K.; Kobilarcik, T.; Kubo, H.; Louis, W. C.; Loverre, P. F.; Ludovici, L.; Mahn, K. B. M.; Mariani, C.; Masuike, S.; Matsuoka, K.; McGary, V. T.; Metcalf, W.; Mills, G. B.; Mitsuka, G.; Miyachi, Y.; Mizugashira, S.; Moore, C. D.; Nakajima, Y.; Nakaya, T.; Napora, R.; Nienaber, P.; Orme, D.; Otani, M.; Russell, A. D.; Sanchez, F.; Shaevitz, M. H.; Shibata, T.-A.; Sorel, M.; Stefanski, R. J.; Takei, H.; Tanaka, H.-K.; Tanaka, M.; Tayloe, R.; Taylor, I. J.; Tesarek, R. J.; Uchida, Y.; van de Water, R.; Walding, J. J.; Wascko, M. O.; White, H. B.; Wilking, M. J.; Yokoyama, M.; Zeller, G. P.; Zimmerman, E. D.; SciBooNE Collaboration

    2010-02-01

    The SciBooNE Collaboration reports inclusive neutral current neutral pion production by a muon neutrino beam on a polystyrene target (C8H8). We obtain (7.7±0.5(stat)±0.5(sys))×10-2 as the ratio of the neutral current neutral pion production to total charged current cross section; the mean energy of neutrinos producing detected neutral pions is 1.1 GeV. The result agrees with the Rein-Sehgal model implemented in our neutrino interaction simulation program with nuclear effects. The spectrum shape of the π0 momentum and angle agree with the model. We also measure the ratio of the neutral current coherent pion production to total charged current cross section to be (0.7±0.4)×10-2.

  17. Twist-2 Light-Cone Pion Wave Function

    OpenAIRE

    Belyaev, V. M.; Johnson, Mikkel B.

    1997-01-01

    We present an analysis of the existing constraints for the twist-2 light-cone pion wave function. We find that existing information on the pion wave function does not exclude the possibility that the pion wave function attains its asymptotic form. New bounds on the parameters of the pion wave function are presented.

  18. Chiral Dynamics in Pion-Photon Reactions Habilitation

    CERN Document Server

    Friedrich, Jan Michael

    As the lightest particle of the strong force, the pion plays a central role in the field of strong interactions, and understanding its properties is of prime relevance for understanding the strong interaction in general. The low-energy behaviour of pions is of particular interest. Although the quark-gluon substructure and their quantum chromodynamics is not apparent then, this specific inner structure causes the presence of approximate symmetries in pion-pion interactions and in pion decays, which gives rise to the systematic description of processes involving pions in terms of few low-energy constants. Specifically, the chiral symmetry and its spontaneous and explicit breaking, treated in chiral perturbation theory (ChPT), leads to firm predictions for low-energy properties of the pion. To those belong the electromagnetic polarisabilities of the pion, describing the leading-order structure effect in pion Compton scattering. The research presented in this work is concerned with the interaction of pions and ph...

  19. Pion production in pd interactions

    Energy Technology Data Exchange (ETDEWEB)

    Greiff, J.; Koch, I.; Scobel, W. [Institut fuer Experimentalphysik Universtaet Hamburg, Hamburg (Germany); Rohdjess, H. [Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany)

    1996-11-01

    Recent experimental data for the reaction pd {yields} pd{pi}{sup 0} in the pion momentum range {eta} = p{sup {pi}}{sub c.m.max}/m{sub {pi}c} {<=} 0.96 is discussed. The excitation function {sigma}{sub pd{pi}}(Tp) roughly follows a {eta}{sup 4} power law for Ss wave interaction; close to threshold it is compatible with that for pd {yields} {sup 3}He{pi}, i.e. a strong spin-doublet interaction. The model of a quasi-free elementary process np {yields} nd{pi}{sup 0} with a spectator proton describes {pi}{sub pd{pi}}(Tp), too, but does not exhaust the observed spectator energy spectra. Comparison to isospin related pd{yields}nd{pi}{sup +} data indicates another reaction mechanism contributing with a strength comparable to that of the quasi-free process. (author) 7 refs, 3 figs

  20. A Spin-parity Analysis Of The Reaction Antiproton Proton Going To Positive Pion Negative Pion Neutral Pion Omega Meson (proton, Antiproton, Pion, Omega Meson)

    CERN Document Server

    McCrady, R G

    1998-01-01

    An analysis of the reaction pp→ p+p-p ow is presented. The annihilations took place at rest in liquid hydrogen. This measurement finds that p+p-po w is produced in 16.1 ± 1.0565544f such annihilations. A prominent signal of pp→ ww is observed. The rate for this process was measured using a technique which is practically background free; the measured rate is BRpp→ ww =3.23± 0.25% . This rate is important in calculations concerning pp annihilation dynamics. A partial wave analysis was also performed. New results include possible observation of ω π π decay modes for the a1(1260), h1(1170) and a1(1700) . These results need confirmation. Also, the b1π decay mode of the ω (1600) is found to be stronger than the ω (π π )s decay mode: BRw1600 → b1p/BR w1600→ w pps =1.6± 0.2. .

  1. S-wave pion absorption by nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, F.; Huefner, J.; Pirner, H.J.

    1976-01-01

    The absorption of pions by nuclei leads to an imaginary part in the optical potential for pionic atoms. The imaginary part is calculated by assuming the rescattering mechanism to dominate. The pion scatters off-shell by one nucleon and is absorbed by a second one. The ..pi..N scattering amplitude is constructed from a field theoretical model. Its off-mass shell properties prove important to reproduce the data.

  2. Pion electroproduction in a nonrelativistic theory

    OpenAIRE

    Fuhrer, Andreas

    2010-01-01

    A nonrelativistic effective theory to describe the electroproduction reaction of a single pion on the nucleon at leading order in the electromagnetic coupling is constructed. The framework is tailored to accurately describe the cusp generated by the pion and nucleon mass differences. The S- and P- wave multipole amplitudes at two loops for all four reaction channels are provided. As an application, a new low energy theorem is discussed.

  3. Pion electroproduction in a nonrelativistic theory

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrer, Andreas, E-mail: afuhrer@physics.ucsd.ed [University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0319 (United States)

    2010-08-23

    A nonrelativistic effective theory to describe the electroproduction reaction of a single pion on the nucleon at leading order in the electromagnetic coupling is constructed. The framework is tailored to accurately describe the cusp generated by the pion and nucleon mass differences. The S- and P-wave multipole amplitudes at two loops for all four reaction channels are provided. As an application, a new low energy theorem is discussed.

  4. Pion photoproduction in a nonrelativistic theory

    OpenAIRE

    Fuhrer, Andreas

    2009-01-01

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes for all four reaction channels at two loops are given.

  5. Pion photoproduction in a nonrelativistic theory

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrer, Andreas, E-mail: afuhrer@physics.ucsd.ed [University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0319 (United States)

    2010-01-18

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes for all four reaction channels at two loops are given.

  6. How sensitive are high-pt electron spectra at RHIC to heavy quark energy loss?

    CERN Document Server

    Armesto, N; Dainese, A; Salgado, C A; Wiedemann, Urs Achim

    2006-01-01

    In nucleus-nucleus collisions, high-pt electron spectra depend on the medium modified fragmentation of their massive quark parents, thus giving novel access to the predicted mass hierarchy of parton energy loss. Here we calculate these spectra in a model, which supplements the perturbative QCD factorization formalism with parton energy loss. In general, we find - within large errors - rough agreement between theory and data on the single inclusive electron spectrum in pp, its nuclear modification factor, and its azimuthal anisotropy. However, the nuclear modification factor depends on the relative contribution of charm and bottom production, which we find to be affected by large perturbative uncertainties. In order for electron measurements to provide a significantly more stringent test of the expected mass hierarchy, one must then disentangle the b- and c-decay contributions, for instance by reconstructing the displaced decay vertices.

  7. Elastic and inelastic pion reactions on few nucleon systems

    Energy Technology Data Exchange (ETDEWEB)

    Lensky, V.

    2007-09-29

    In the present work, we are studying elastic and inelastic pion reactions on few-body systems within the framework of chiral effective theory. We consider two specific reactions involving pions on few-nucleon systems, namely pion production in nucleon-nucleon collisions, and incoherent pion photoproduction on the deuteron. These two reactions are closely related to the issue of dispersive and absorptive corrections to the pion-deuteron scattering length, which we also consider in our analysis. The incoherent pion photoproduction is also considered as the possible source for a high-precision determination of the neutron-neutron scattering length. (orig.)

  8. Investigation of pion-nucleus interactions. Progress report, April 1, 1991--March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Moore, C.F.

    1992-09-01

    This report summarizes the work carried out by personnel from the University of Texas at Austin at the Los Alamos Clinton P. Anderson Meson Physics Facility (LAMPF). The research activities involved experiments done with the Energetic Pion Channel and Spectrometer (EPICS), the Low Energy Pion Channel (LEP), the Pion and Particle Physics Channel (P{sup 3}), the High Resolution Spectrometer (HRS), and planning a new experimental program associated with the new high-resolution Neutral Meson Spectrometer (NMS) at LAMPF. A brief overview of work supported by this grant is given followed by an account of the study of the double giant resonances in pion double charge exchange on {sup 51}V, {sup 115}In, and {sup 197}Au. This report contains a list of published papers and preprints, abstracts, and invited talks. These papers summarize experiments involving participants supported by this grant and indicate the work accomplished by these participants in this program of medium energy nuclear physics research. Lists of the most recent proposals on which we have participation at LAMPF, proposals which have been approved this past year to run as experiments, personnel who have participated in this research program are included. The research cited in this report is, in many cases, the collaborative effort of many groups associated with research at LAMPF.

  9. The pion form factor from analyticity and unitarity

    Indian Academy of Sciences (India)

    Analyticity and unitarity techniques are employed to estimate Taylor coefficients of the pion electromagnetic form factor at = 0 by exploiting the recently evaluated two-pion contribution to the muon ( − 2) and the phase of the pion electromagnetic form factor in the elastic region, known from scattering by ...

  10. Measurement of charged pions in 12C + 12C collisions at 1 A GeV and 2 A GeV with HADES

    Science.gov (United States)

    Agakishiev, G.; Agodi, C.; Balanda, A.; Bellia, G.; Belver, D.; Belyaev, A.; Bielcik, J.; Blanco, A.; Bortolotti, A.; Boyard, J. L.; Braun-Munzinger, P.; Cabanelas, P.; Chernenko, S.; Christ, T.; Coniglione, R.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Durán, I.; Dybczak, A.; Eberl, T.; Fabbietti, L.; Fateev, O.; Ferreira-Marques, R.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Grosse, E.; Guber, F.; Heilmann, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Kozuch, A.; Krása, A.; Křížek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lamas-Valverde, J.; Lang, S.; Lange, J. S.; Lapidus, K.; Lopes, L.; Lorenz, M.; Maier, L.; Maiolino, C.; Mangiarotti, A.; Marín, J.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Morinière, E.; Mousa, J.; Münch, M.; Müntz, C.; Naumann, L.; Novotny, R.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pérez Cavalcanti, T.; Piattelli, P.; Pietraszko, J.; Pospíšil, V.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Sapienza, P.; Schmah, A.; Schroeder, C.; Schwab, E.; Simon, R. S.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Tarantola, A.; Teilab, K.; Tlustý, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.; Zhou, P.; Zumbruch, P.

    2009-04-01

    We present the results of a study of charged-pion production in 12C + 12C collisions at incident beam energies of 1A GeV and 2A GeV using the HADES spectrometer at GSI. The main emphasis of the HADES program is on the dielectron signal from the early phase of the collision. Here, however, we discuss the data with respect to the emission of charged hadrons, specifically the production of π^{{±}}_{} mesons, which are related to neutral pions representing a dominant contribution to the dielectron yield. We have performed the first large-angular-range measurement of the distribution of π^{{±}}_{} mesons for the 12C + 12C collision system covering a fairly large rapidity interval. The pion yields, transverse-mass and angular distributions are compared with calculations done within a transport model, as well as with existing data from other experiments. The anisotropy of pion production is systematically analyzed.

  11. Pion-induced damage in silicon detectors

    CERN Document Server

    Bates, S; Glaser, M; Lemeilleur, F; León-Florián, E; Gössling, C; Kaiser, B; Rolf, A; Wunstorf, R; Feick, H; Fretwurst, E; Lindström, G; Moll, Michael; Taylor, G; Chilingarov, A G

    1995-01-01

    The damage induced by pions in silicon detectors is studied for positive and negative pions for fluence up to 10(14)cm-2 and 10(13) cm-2 respectively. Results on the energy dependence of the damage in the region of 65-330 MeV near to the  resonance are presented. The change in detector characteristics such as leakage current, charge collection efficiency and effective impurity concentration including long-term annealing effects have been studied. Comparisons to neutron and proton-induced damage are presented and discussed.

  12. Positivity Constraints on Chiral Perturbation Theory Pion-Pion Scattering Amplitudes

    CERN Document Server

    Dita, P

    1999-01-01

    We test the positivity property of the chiral perturbation theory (ChPT) pion-pion scattering amplitudes within the Mandelstam triangle. In the one-loop approximation, ${\\cal O}(p^4)$, the positivity constrains only the coefficients $b_3$ and $b_4$, namely one obtains that $b_4$ and the linear combination $b_3+3 b_4$ are positive quantities. The two-loops approximation gives inequalities involving all the six arbitrary parameters entering ChPT amplitude, but the corrections to the one-loop approximation results are small. ChPT amplitudes pass unexpectedly well all the positivity tests giving strong support to the idea that ChPT is the good theory of the low energy pion-pion scattering.

  13. Precision tracking and electromagnetic calorimetry towards a measurement of the pion polarisabilities at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Dinkelbach, Anna-Maria Elisabeth

    2010-07-20

    In 2004 the COMPASS experiment at CERN SPS measured soft reactions with a beam of negatively charged pions on various nuclear targets. For this measurement, a silicon micro-strip telescope was installed in the target region. For the first time 5 silicon detector stations were operated simultaneously in the COMPASS experiment. A novel method of time calibration, with a clustering algorithm accordingly adapted, and refined alignment corrections were implemented in the analysis software. The spatial resolution of a silicon detector was determined to be 5 - 14 {mu}m and the time resolution 2 - 3 ns. Combining the time information of all stations, a track time resolution of 530 ps from the silicon telescope could be reached. One of the key points of this experiment was the observation of Primakoff events, namely pions scattering off quasi-real photons in the Coulomb field of a heavy nucleus. The production of real photons corresponds to pion Compton scattering in inverse kinematics which is sensitive to the pion polarisabilities {alpha}{sub {pi}} and {beta}{sub {pi}}. Key ingredient for such measurements is a precise knowledge of the performance of the electromagnetic calorimeter. This includes a study of the instabilities of calorimeter cells and an improved reconstruction algorithm. A data-driven shower model was developed, which was used for a timedependent recalibration of the calorimeter. A new cluster refitting method was used to recover position and energy of clusters containing passive or saturated cells and detects double-hit clusters. The latter are important, as the main background to the Primakoff Compton events stems from neutral pions misinterpreted as single-photon hits. The physics analysis comprised the selection of Primakoff events and the necessary steps to obtain the pionic polarisabilities. The measurement was limited by systematic effects of the apparatus also determined within this thesis. (orig.)

  14. Relativistic mean field theory with the pion for finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, S.; Toki, H.; Ikeda, K.; Minkov, N

    2003-07-14

    We study the possible occurrence of finite pion mean field in finite nuclei in the relativistic mean field (RMF) theory. We calculate explicitly various N = Z closed-shell nuclei with finite pion mean field in the RMF theory with the standard parameter set and the pion-nucleon coupling in free space. The finite pion mean field is introduced by breaking the parity symmetry of intrinsic single-particle states. We demonstrate the actual occurrence and the property of the finite pion mean field.

  15. Page 1 Pions 17.2 GeV Pion-Nucleus Interactions in Emulsion ...

    Indian Academy of Sciences (India)

    Pions 17.2 GeV Pion-Nucleus Interactions in Emulsion Nuclei. 9. Caforio, A., Ferrara, D., Nuovo Cimento, 1964, 32, 1471. Semeraro, S., Fisher, C. M.,. Mason, A., Venus, W.A.,. Evans, D., Hossain, A.,. Wortuba, M. F., Watoghin,. A., Kasim, M. M.,. Shaukat, M. S., Herz,. A. J., Sichirollo, A. S. and Vegni, G. 10. Rinaldo, J. D., Jain ...

  16. RPA correlation effects in radiative pion capture

    Energy Technology Data Exchange (ETDEWEB)

    Krivine, H.; Lipparini, E.; Navarro, J.; Roig, F.

    1988-05-16

    A sum rule approach to radiative pion capture is given in terms of the energy-weighted and inverse-energy weighted sum rules. They are evaluated with RPA accuracy for Skyrme-like interactions. The static polarizabilities of the dipole, quadrupole and octupole isovector modes turn out to be the relevant quantities to determine the total branching ratios and mean photon energies.

  17. Exclusive electroproduction of two pions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H.; Ashery, D.; Gueta, O.; Gurvich, E.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A. [Tel Aviv Univ., Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv (Israel); Abt, I.; Caldwell, A.; Reisert, B.; Schmidke, W.B. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L.; Bold, T.; Gach, G.; Grabowska-Bold, I.; Guzik, M.; Kisielewska, D.; Przybycien, M.; Suszycki, L. [AGH-Univ. of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow (Poland); Adamus, M.; Plucinski, P.; Tymieniecka, T. [National Centre for Nuclear Research, Warsaw (Poland); Aggarwal, R.; Kaur, M.; Kaur, P.; Singh, I. [Panjab Univ., Dept. of Physics, Chandigarh (India); Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A. [Univ. Bologna (Italy); INFN Bologna (Italy); Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Margotti, A.; Nania, R.; Polini, A. [INFN Bologna (Italy); Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S. [Moscow Engineering Physics Inst., Moscow (Russian Federation); Arneodo, M.; Ruspa, M. [Univ. del Piemonte Orientale, Novara, (Italy); INFN, Torino (Italy); Aushev, V.; Dolinska, G.; Gogota, O.; Korol, I.; Viazlo, O. [National Academy of Sciences, Inst. for Nuclear Research, Kyiv (Ukraine); National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Aushev, Y.; Bartosik, N.; Bondarenko, K.; Kadenko, I.; Onishchuk, Yu.; Salii, A.; Tomalak, O.; Volynets, O.; Zolko, M. [National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Bachynska, O.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Bot, D.; Ciesielski, R.; Coppola, N.; Fang, S.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany)] [and others

    2012-01-15

    The exclusive electroproduction of two pions in the mass range 0.4pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, vertical stroke F(M{sub {pi}}{sub {pi}}) vertical stroke, assuming that the studied mass range includes the contributions of the {rho}, {rho}' and {rho}'' vector-meson states. The masses and widths of the resonances were obtained and the Q {sup 2} dependence of the cross-section ratios {sigma}({rho}'{yields}{pi}{pi})/ {sigma}({rho}) and {sigma}({rho}''{yields}{pi}{pi})/ {sigma}({rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -}. (orig.)

  18. Pion decay constants in dense skyrmion matter

    Directory of Open Access Journals (Sweden)

    Lee H.-J.

    2010-10-01

    Full Text Available According to the QCD, the hadronic matter can have various phases with matter density and temperature. In general, when there is phase transition in a matter, it is known that a symmetry in the matter changes. In case of the hadronic matter, the chiral symmetry in the matter is expected to be restored when the matter density (or temperature increases. The actual order parameter with respect to the chiral symmetry in the hadronic matter is known as the quark condensate from the QCD, but the pion decay constant, corresponding to the radius of the chiral circle, plays the role of the order parameter in an effective field theoretical approach to the QCD. In this paper, by using the skyrmion model which is an effective theory to the QCD, we construct the skyrmion matter as a model of the hadronic matter (nuclear matter and calculate the pion decay constant in the matter. Because of presence of the matter, the pion decay constant is split into the two components, the temporal component and the spatial component. We discuss the phase transition in the skyrmion matter and behavior of the two components of the decay constant for massless pion with density of the skyrmion matter.

  19. High purity pion beam at TRIUMF

    Science.gov (United States)

    Aguilar-Arevalo, A.; Blecher, M.; Bryman, D. A.; Comfort, J.; Doornbos, J.; Doria, L.; Hussein, A.; Ito, N.; Kettell, S.; Kurchaninov, L.; Malbrunot, C.; Marshall, G. M.; Numao, T.; Poutissou, R.; Sher, A.; Walker, B.; Yamada, K.

    2009-10-01

    An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π+→e+ν is also described.

  20. High Purity Pion Beam at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Kettell, S.; Kettell, S.; Aguilar-Arevalo, A.; Blecher, M.; Bryman, D.A.; Comfort, J.; Doornbos, J.; Doria, L.; Hussein, A.; Ito, N.; et al.

    2009-10-11

    An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay {pi}{sup +} {yields} e{sup +}{nu} is also described.

  1. High purity pion beam at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Arevalo, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Blecher, M. [Physics Department, Virginia Tech., Blacksburg, VA 24061 (United States); Bryman, D.A. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Comfort, J. [Arizona State University, Tempe, AZ 85287 (United States); Doornbos, J.; Doria, L. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Hussein, A. [University of Northern British Columbia, Prince George, BC, V2N 4Z9 (Canada); Ito, N. [Physics Department, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Kettell, S. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Kurchaninov, L. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Malbrunot, C. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Marshall, G.M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Numao, T. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: toshio@triumf.ca; Poutissou, R.; Sher, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Walker, B. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Yamada, K. [Physics Department, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

    2009-10-11

    An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay {pi}{sup +}{yields}e{sup +}{nu} is also described.

  2. Exclusive electroproduction of two pions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-11-15

    The exclusive electroproduction of two pions in the mass range 0.4< M{sub {pi}}{sub {pi}} <2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb{sup -1}. The analysis was carried out in the kinematic range of 2< Q{sup 2}<80 GeV{sup 2}, 32pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, vertical stroke F(M{sub {pi}}{sub {pi}}) vertical stroke, assuming that the studied mass range includes the contributions of the {rho}, {rho}{sup '} and {rho}'' vector-meson states. The masses and widths of the resonances were obtained and the Q{sup 2} dependence of the cross-section ratios {sigma}({rho}{sup '} {yields} {pi}{pi})/{sigma}({rho}) and {sigma}({rho}'' {yields} {pi}{pi})/{sigma}({rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -}. (orig.)

  3. Measurement of the Charged-Pion Polarizability

    CERN Document Server

    Adolph, C; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dinkelbach, A.M.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Hoppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kuchinski, N.; Kuhn, R.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Moinester, M.A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peshekhonov, D.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Rocco, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

    2015-01-01

    The COMPASS collaboration at CERN has investigated pion Compton scattering, $\\pi^-\\gamma\\rightarrow \\pi^-\\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction $\\pi^-\\mathrm{Ni}\\rightarrow\\pi^-\\gamma\\;\\mathrm{Ni}$, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, $Q^2<0.0015$ (GeV/$c$)$^2$. From a sample of 63 000 events the pion electric polarisability is determined to be $\\alpha_\\pi = (2.0 \\pm 0.6_{\\mbox{stat}} \\pm 0.7_{\\mbox{syst}}) \\times 10^{-4} \\mbox{fm}^3$ under the assumption $\\alpha_\\pi=-\\beta_\\pi$, which relates the electric and magnetic dipole polarisabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction, that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is fou...

  4. Exclusive electroproduction of two pions at HERA

    CERN Document Server

    Abramowicz, H.

    2012-01-25

    The exclusive electroproduction of two pions in the mass range 0.4 < M{\\pi}{\\pi} < 2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The analysis was carried out in the kinematic range of 2 < Q2 < 80 GeV2, 32 < W < 180 GeV and |t| < 0.6 GeV2, where Q2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(M{\\pi}{\\pi})|, assuming that the studied mass range includes the contributions of the {\\rho}, {\\rho}' and {\\rho}" vector-meson states. The masses and widths of the resonances were obtained and the Q2 dependence of the cross-section ratios {\\sigma}({\\rho}' \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) and {\\sigma}({\\rho}" \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained...

  5. Study of pion photo-production using a TPC detector to determine beam asymmetries from polarized HD

    Science.gov (United States)

    Kizilgul, Serdar A.

    The Laser Electron Gamma Source facility (LEGS) provides intense, polarized, tagged gamma-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the NSLS at BNL, Upton, NY. A series of double-polarization experiments (beam and target) has been completed to study the helicity structure of the nucleon. Neutral-pion measurements were completed in 2005 by using the Spin ASYmmetry detector system (SASY) which covers a large solid angle and allows for detection of a large range of neutral pions. Charged-pion experiments were completed in 2006. This new experiment yields data on the beam asymmetry Sigma for a polarized Hydrogen Deuterium (HD) target from the 2006 data. A Time Projection Chamber (TPC), surrounded by two-Tesla magnet, was built and incorporated into SASY to identify the pion charge and so separate neutron and proton reactions. The TPC provides snap-shots of ionizing tracks of particles produced by 300-422 MeV polarized photons on a polarized HD target. A polarized HD target was developed and used in these experiments.

  6. Search for Neutral Q-balls in Super-Kamiokande II

    CERN Document Server

    Takenaga, Y; Hayato, Y; Iida, T; Ishihara, K; Kameda, J; Koshio, Y; Minamino, A; Mitsuda, C; Miura, M; Moriyama, S; Nakahata, M; Obayashi, Y; Ogawa, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takeuchi, Y; Ueshima, K; Higuchi, I; Ishihara, C; Ishitsuka, M; Kajita, T; Kaneyuki, K; Mitsuka, G; Nakayama, S; Nishino, H; Okumura, K; Saji, C; Totsuka, Y; Clark, S; Desai, S; Dufour, F; Herfurth, A; Kearns, E; Likhoded, S; Litos, M; Raaf, Jennifer L; Stone, J L; Sulak, L R; Wang, W; Goldhaber, M; Casper, D; Cravens, J P; Dunmore, J; Griskevich, J; Kropp, W R; Liu, D W; Mine, S; Regis, C; Smy, M B; Sobel, H W; Vagins, M R; Ganezer, K S; Hill, J E; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Scholberg, K; Tanimoto, N; Walter, C W; Wendell, R; Ellsworth, R W; Tasaka, S; Guillian, E; Learned, J G; Matsuno, S; Messier, M D; Ichikawa, A K; Ishida, T; Ishii, T; Iwashita, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Nitta, K; Oyama, Y; Suzuki, A T; Hasegawa, M; Hiraide, K; Kato, I; Maesaka, H; Nakaya, T; Sasaki, T; Sato, H; Yamamoto, S; Yokoyama, M; Haines, T J; Dazeley, S; Hatakeyama, S; Svoboda, R; Sullivan, G W; Gran, R; Habig, A; Fukuda, Y; Sato, T; Itow, Y; Koike, T; Jung, C K; Kato, T; Kobayashi, K; Malek, M; McGrew, C; Sarrat, A; Terri, R; Yanagisawa, C; Tamura, N; Sakuda, M; Sugihara, M; Kuno, Y; Yoshida, M; Kim, S B; Yoo, J; Ishizuka, T; Okazawa, H; Choi, Y; Seo, H K; Gando, Y; Hasegawa, T; Inoue, K; Ishii, H; Nishijima, K; Ishino, H; Watanabe, Y; Koshiba, M; Chen, S; Deng, Z; Liu, Y; Kielczewska, D; Zalipska, J; Berns, H G; Shiraishi, K K; Washburn, K; Wilkes, R J; al, et

    2007-01-01

    A search for Q-balls induced groups of successive contained events has been carried out in Super-Kamiokande II with 541.7 days of live time. Neutral Q-balls would emit pions when colliding with nuclei, generating a signal of successive contained pion events along a track. No candidate for successive contained event groups has been found in Super-Kamiokande II, so upper limits on the possible flux of such Q-balls have been obtained.

  7. Measurements of observables in the pion-nucleon system, nuclear a- dependence of heavy quark production and rare decays of D and B mesons

    Energy Technology Data Exchange (ETDEWEB)

    Sadler, M.E.; Isenhower, L.D.

    1992-02-15

    This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments. (LSP)

  8. Pion contamination in the MICE muon beam

    CERN Document Server

    Bogomilov, M.; Vankova-Kirilova, G.; Bertoni, R.; Bonesini, M.; Chignoli, F.; Mazza, R.; Palladino, V.; de Bari, A.; Cecchet, G.; Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L.; Kuno, Y.; Sakamoto, H.; Ishimoto, S.; Japan, Ibaraki; Filthaut, F.; Hansen, O.M.; Ramberger, S.; Vretenar, M.; Asfandiyarov, R.; Blondel, A.; Drielsma, F.; Karadzhov, Y.; Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Oates, A.; Owens, P.; Stokes, G.; Warburton, P.; White, C.; Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A.; Bayes, R.; Nugent, J.C.; Soler, F.J.P.; Cooke, P.; Gamet, R.; Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Hunt, C.; Lagrange, J-B.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Santos, E.; Savidge, T.; Uchida, M.A.; Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D.; Booth, C.N.; Hodgson, P.; Langlands, J.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J.; Dick, A.; Ronald, K.; Speirs, D.; Whyte, C.G.; Young, A.; Boyd, S.; Franchini, P.; Greis, J.R.; Pidcott, C.; Taylor, I.; Gardener, R.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R.; Roberts, T.J.; Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.; Zisman, M.; Drews, M.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y.; Winter, M.; Blot, S.; Kim, Y.K.; Bravar, U.; Onel, Y.; Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J.; Cline, D.; Yang, X.; Coney, L.; Hanson, G.G.; Heidt, C.

    2016-01-01

    The international Muon Ionization Cooling Experiment (MICE) will perform a systematic investigation of ionization cooling with muon beams of momentum between 140 and 240\\,MeV/c at the Rutherford Appleton Laboratory ISIS facility. The measurement of ionization cooling in MICE relies on the selection of a pure sample of muons that traverse the experiment. To make this selection, the MICE Muon Beam is designed to deliver a beam of muons with less than $\\sim$1\\% contamination. To make the final muon selection, MICE employs a particle-identification (PID) system upstream and downstream of the cooling cell. The PID system includes time-of-flight hodoscopes, threshold-Cherenkov counters and calorimetry. The upper limit for the pion contamination measured in this paper is $f_\\pi < 1.4\\%$ at 90\\% C.L., including systematic uncertainties. Therefore, the MICE Muon Beam is able to meet the stringent pion-contamination requirements of the study of ionization cooling.

  9. Exclusive electroproduction of two pions at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Ashery, D.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Gurvich, E.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Huettmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H. -P.; Januschek, F.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I. -A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zolko, M.; Zotkin, D. S.

    The exclusive electroproduction of two pions in the mass range 0.4

  10. Two Photon Exchange for Exclusive Pion Electroproduction

    Energy Technology Data Exchange (ETDEWEB)

    Afanaciev, Andrei V. [George Washington U.; Aleksejevs, Aleksandrs G. [Memorial University of Newfoundland, Newfoundland, Canada; Barkanova, Svetlana G. [Acadia University, Nova Scotia, Canada

    2013-09-01

    We perform detailed calculations of two-photon-exchange QED corrections to the cross section of pion electroproduction. The results are obtained with and without the soft-photon approximation; analytic expressions for the radiative corrections are derived. The relative importance of the two-photon correction is analyzed for the kinematics of several experiments at Jefferson Lab. A significant, over 20%, effect due to two-photon exchange is predicted for the backward angles of electron scattering at large transferred momenta.

  11. Measurement of the charged-pion polarisability at COMPASS

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    For more than a decade, COMPASS has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpukhov (Russia), where the Primakoff method for realizing interactions of charged pions with quasi-real photons was first employed. Later also other techniques in photon-nucleon and photon-photon collisions were carried out at different machines. The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous results, roughly by a factor two, with the smallest uncertainties realized so far. The pion polarisability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and dynamics of the pion, the lightest bound system of strong interaction.

  12. New Precise Measurement of the Pion Weak Form Factors in the Pi+ -> e+ nu gamma Decay

    CERN Document Server

    Bychkov, M; VanDevender, B A; Baranov, V A; Bertl, W; Bystritsky, Yu M; Frlež, E; Kalinnikov, V A; Khomutov, N V; Korenchenko, A S; Korenchenko, S M; Korolija, M; Kozlovskii, T; Kravchuk, N P; Kuchinskii, N A; Li, W; Mekterović, D; Mzhavia, D; Ritt, S; Robmann, P; Rondon-Aramayo, O A; Rozhdestvensky, A M; Sakhelashvili, T; Scheu, S; Straumann, U; Supek, I; Tsamalaidze, Z; Van der Schaaf, A; Velicheva, E P; Volnykh, V P; Wang, Y; Wirtz, H -P

    2008-01-01

    We have measured the radiative pion decay branching ratio over a wide region of phase space, based on a total of 65,460 events acquired using the PIBETA detector. Fits to the measured energy distributions result in the weak form factor value of F_A = 0.0119(1) with a fixed value of F_V = 0.0259. An unconstrained fit yields F_V = 0.0258(17) and F_A = 0.0117(17). In addition, we have measured a = 0.095(58) for the dependence of F_V on the lepton pair invariant mass. The branching ratio for the kinematic region with E(gamma) > 10 MeV and Theta(e+,gamma) > 40 degrees is measured to be B = 73.86(54)x10^{-8}. Earlier deviations we reported in the high-E(gamma)/low-E(e+) kinematic region are resolved, and we find full compatibility with CVC and standard V-A calculations without a tensor term. We also derive new values for the pion polarizability alpha_E = 2.78(10)x10^{-4} fm^3, and neutral pion lifetime, tau_{pi0} = (8.5+-1.1)x10^{-17} s.

  13. A Lower Bound on Inelasticity in Pion-Pion Scattering arXiv

    CERN Document Server

    Martin, André

    Assuming that the pion-pion scattering amplitude and its absorptive part are analytic inside an ellipse in $t$- plane with foci $t=0$, $u=0$ and right extremity $t=4 m_{\\pi}^2 +\\epsilon $, ($\\epsilon > 0$), except for cuts prescribed by Mandelstam representation for $t\\geq 4 m_{\\pi}^2$, $u\\geq 4 m_{\\pi}^2$ , and bounded by $s^N$ on the boundary of this domain, we prove that for $s\\rightarrow \\infty$, \\sigma_{inel} (s) > \\frac{Const}{s^{5/2} }\\exp {[-\\frac{\\sqrt{s}}{4} (N+5/2) \\ln {s} ]}.

  14. Characterization of ParTI Phoswiches Using Charged Pion Beams

    Science.gov (United States)

    Churchman, Emily; Zarrella, Andrew; Youngs, Michael; Yennello, Sherry

    2017-09-01

    The Partial Truncated Icosahedron (ParTI) detector array consists of 15 phoswiches. Each phoswich is made of two scintillating components - a thallium-doped cesium iodide (CsI(Tl)) crystal and an EJ-212 scintillating plastic - coupled to a photomultiplier tube. Both materials have different scintillation times and are sensitive to both charged and neutral particles. The type of particle and amount of energy deposited determine the shape of the scintillation pulse as a function of time. By integrating the fast and slow signals of the scintillation pulses, a ``Fast vs. Slow Integration'' plot can be created that produces particle identification lines based on the energy deposited in the scintillating materials. Four of these phoswiches were taken to the Paul Scherrer Institute (PSI) in Switzerland where π + , π-, and proton beams were scattered onto the phoswiches to demonstrate their particle identification (PID) capabilities. Using digitizers to record the detector response waveforms, pions can also be identified by the characteristic decay pulse of the muon daughters.

  15. Frascati results suggest the pion may be pointlike

    CERN Multimedia

    1971-01-01

    Electron-positron collisions at the Adone storage ring have yielded suprisingly high cross-sections for the production of strongly interacting particles such as positive and negative pion pairs. Some physicists are interpreting these results as meaning that the pion may have pointlike constituents or behaves like a structureless particle like the electron or muon (4 paragraphs).

  16. The pion form factor from analyticity and unitarity

    Indian Academy of Sciences (India)

    2012-11-15

    Nov 15, 2012 ... to the muon (g − 2) and the phase of the pion electromagnetic form factor in the elastic region, known from ππ ... Introduction. The pion electromagnetic form factor Fπ (t) is an important object to account for a vari- ... problem of the zeros, and obtain regions in the complex t-plane where zeros are excluded. 2.

  17. Limits on Lorentz violation from charged-pion decay

    NARCIS (Netherlands)

    P. Noordmans, J.; K. Vos, K.

    2014-01-01

    Charged-pion decay offers many opportunities to study Lorentz violation. Using an effective field theory approach, we study Lorentz violation in the lepton, W-boson, and quark sectors and derive the differential pion-decay rate, including muon polarization. Using coordinate redefinitions we are able

  18. Pion Electromagnetic Form Factor in Virtuality Distribution Formalism

    Energy Technology Data Exchange (ETDEWEB)

    Radyushkin, Anatoly V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)

    2016-01-01

    We discuss two applications of the {\\it Virtuality Distribution Amplitudes} (VDA) formalism developed in our recent papers. We start with an overview of the main properties of the pion distribution amplitude emphasizing the quantitative measures of its width, and possibility to access them through the pion transition form factor studies. We formulate the basic concepts of the VDA approach and introduce the pion {\\it transverse momentum distribution amplitude} (TMDA) which plays, in a covariant Lagrangian formulation, a role similar to that of the pion wave function in the 3-dimensional Hamiltonian light-front approach. We propose simple factorized models for soft TMDAs, and use them to describe existing data on the pion transition form factor, thus fixing the scale determining the size of the transverse-momentum effects. Finally, we apply the VDA approach to the one-gluon exchange contribution for the pion electromagnetic form factor. We observe a very late $Q^2 \\gtrsim 20$ GeV$^2$ onset of transition to the asymptotic pQCD predictions and show that in the $Q^2 \\lesssim 10$ GeV$^2$ region there is essentially no sensitivity to the shape of the pion distribution amplitude. Furthermore, the magnitude of the one-gluon exchange contribution in this region is estimated to be an order of magnitude below the Jefferson Lab data, thus leaving the Feynman mechanism as the only one relevant to the pion electromagnetic form factor behavior for accessible $Q^2$.

  19. End point behaviour of the pion distribution amplitude

    Science.gov (United States)

    Szcepaniak, Adam; Mankiewicz, Lech

    1991-08-01

    We study the end point structure of the pion distribution amplitude and reexamine the perturbative analysis of the high-Q2 pion form factor in the factorization approach. Permanent address: Nicolaus Copernicus Astronomical Centre, Bartycka 18, PL-00-716 Warsaw, Poland.

  20. Two-pion production in photon-induced reactions

    Indian Academy of Sciences (India)

    A deeper understanding of the situation is anticipated from a detailed experimental study of meson photoproduction from nuclei in exclusive reactions. In the energy regime above the (1232) resonance, the dominant double pion production channels are of particular interest. Double pion photoproduction from nuclei is ...

  1. Rare kaon, muon, and pion decay

    Energy Technology Data Exchange (ETDEWEB)

    Littenberg, L.

    1998-12-01

    The author discusses the status of and prospects for the study of rare decays of kaons, muons, and pions. Studies of rare kaon decays are entering an interesting new phase wherein they can deliver important short-distance information. It should be possible to construct an alternative unitarity triangle to that determined in the B sector, and thus perform a critical check of the Standard Model by comparing the two. Rare muon decays are beginning to constrain supersymmetric models in a significant way, and future experiments should reach sensitivities which this kind of model must show effects, or become far less appealing.

  2. Nuclear transparencies from photoinduced pion production

    Energy Technology Data Exchange (ETDEWEB)

    W. Cosyn; M.C. Martinez; J. Ryckebusch; B. Van Overmeire

    2006-12-01

    We present a relativistic and cross-section factorized framework for computing nuclear transparencies extracted from A({gamma}, {pi} N) reactions at intermediate energies. The proposed quantum mechanical model adopts a relativistic extension to the multiple-scattering Glauber approximation to account for the final state interactions of the ejected nucleon and pion. The theoretical predictions are compared against the experimental {sup 4}He({gamma},p {pi}{sup -}) data from Jefferson Lab. For those data, our results show no conclusive evidence for the onset of mechanisms related to color transparency.

  3. Pion polarizabilities: ChPT vs Experiment

    Directory of Open Access Journals (Sweden)

    Ivanov Mikhail A.

    2016-01-01

    Full Text Available The values of charged pion polarizabilities obtained in the framework of chiral perturbation theory at the level of two-loop accuracy are compared with the experimental result recently reported by COMPASS Collaboration. It is found that the calculated value for the dipole polarizabilities (α − βπ± = (5.7 ± 1.0 × 10−4 fm3 fits quite well the experimental result (α − βπ± = (4.0 ± 1.2stat ± 1.4syst × 10−4 fm3.

  4. Subthreshold production of pions in coincidence with light particles

    Energy Technology Data Exchange (ETDEWEB)

    Barbera, R.; Badala, A.; Adorno, A.; Bonasera, A.; Di Toro, M.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, G. (Istituto Nazionale di Fisica Nucleare, Catania (Italy)); Bizard, G.; Durand, D.; Laville, J.L. (Caen Univ., 14 (France). Lab. de Physique Corpusculaire); Jin, G.M. (Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)); Rosato, E. (Naples Univ. (Italy). Dipt. di Scienze Fisiche Istituto Nazionale di Fisica Nucleare, Naples (Italy))

    1990-12-03

    He ions have been detected in coincidence with charged pions in the reaction {sup 16}O on {sup 27}Al at E{sub lab}=94 MeV/u. We analyse velocity spectra and cross-sections of He ions emitted in the angular range 4deg/150deg in coincidence with charged pions detected at 90deg. A two source emission mechanism of the helium particles and a pion statistical production from an equilibrated participant zone is stressed. The absolute yields at different angles are compared with results of a theoretical model for medium energy heavy ion reactions in the frame of a participant-spectator picture. A comparison of the pion energy spectra with Boltzmann-Nordheim-Vlasov calculations and a discussion on the time scale for pion emission is also presented. (orig.).

  5. Neutral currents

    CERN Document Server

    AUTHOR|(CDS)2069482

    1986-01-01

    The present status of weak neutral currents is reviewed. F.mphasis is put on the comparison of recent experimental results with earlier ones, and with predictions of gauge models of the SU(Z) ® U(l) type. The coupling constants governing the weak neutral current interaction are given, and their quantitative agreement with the Salam-Weinberg model is critically examined. 1. INrRODUCT ION 25 The last year has been a period of consolidation for neutral current physics. Important new results and improvements of old results have been reported, but our picture of the neutral current interaction did not change compared to that of one year ago 1 • 2). Hence the emphasis of this review is put on recent experimental results, and on a critical discussion of the precision of those experiments which yield the most stringent constraints on model parameters. The processes which can occur via the weak neutral current interaction are depicted in the "Sakurai tetragon" 3) which is shown in Fig. 1. It is an analogue to the P...

  6. Off-shell effects in s-wave pion absorption

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, F.; Pirnerdouble-dagger, H.J.

    1978-06-01

    The effect of s-wave pion absorption on the pion-nucleus optical potential is calculated. We assume absorption by two uncorrelated nucleons with off-shell pion rescattering. For the pion-nucleon interaction we develop a field theoretic model which can be used on- and off-mass shell. A fully relativistic calculation of the pion polarization operator then gives U/sup opt/ =-4..pi..B/sub orho//sup 2/(2..mu..)/sup -1/, with B/sub 0/= (0.094+i0.036) ..mu../sup -4/, as contribution from s-wave absorption to the optical potential. The imaginary part agrees well with the experimentally determined value, while pion dispersion (real part of B/sub o/) does not explain the observed repulsion of the s-wave pion nucleus interaction. We deomonstrate the relevance of oo-shell dynamics in pion-nucleus scattering. The ratio R/sub s/ of ..pi../sup -/-absorption rates by neutron-proton and proton-proton pairs is much smaller than predicted by on-shell models. For equal numbers of neutrons and protons we get R/sub s/approx. =3.0.We also apply the formalism to s-wave pion production in nucleon-nucleon collisions and obtain qualitative agreement with the data. In particular the longstanding puzzle of the small imaginary pion deuteron scattering length compared to Im B/sub 0/ is explained. Our claculation gives Im a/sub pid/=3.7 x 10/sup -3/..mu../sup -1/.

  7. Branching Ratio Measurements Of B Meson Decays To J/psi Meson Eta Meson Kaon And Charged B Meson Decays To Neutral D Meson Charged Kaon With Neutral D Meson Decays To Positive Pion Negative Pion Neutral Pion

    CERN Document Server

    Zeng, Q

    2005-01-01

    Results are presented for the decays of B → J/ψηK and B± → DK±, respectively, with experimental data collected with BABAR detector at PEP-II, located at Stanford Linear Accelerator Center (SLAC). With 90 × 106 BB¯ events at the ϒ(4S) resonance, we obtained branching fractions of B (B± → J/ψηK ±) = [10.8 ± 2.3(stat) ± 2.4(syst)] × 10−5 and B (B0 → J/ψη K0S ) = [8.4 ± 2.6(stat) ± 2.7( syst)] × 10−5; and we set an upper limit of B [B± → X(3872) K± → J/ψηK ±] < 7.7 × 10−6 at 90% confidence level. The branching fraction of decay chain B (B± → DK ± → π+π−π 0K±) = [5.5 ± 1.0( stat) &...

  8. Joint resummation for pion wave function and pion transition form factor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hsiang-nan [Institute of Physics, Academia Sinica,Academia Rd., Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University,University Rd., Tainan, Taiwan 701 (China); Department of Physics, National Tsing-Hua University,Kuang-Fu Rd., Hsinchu, Taiwan 300 (China); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Rd, Qingdao, Shandong 266100 (China); Wang, Yu-Ming [Institut für Theoretische Teilchenphysik und Kosmologie RWTH Aachen,Physikzentrum Otto-Blumenthal-Straße, D-52056 Aachen (Germany); Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)

    2014-01-03

    We construct an evolution equation for the pion wave function in the k{sub T} factorization formalism, whose solution sums the mixed logarithm ln xln k{sub T} to all orders, with x (k{sub T}) being a parton momentum fraction (transverse momentum). This joint resummation induces strong suppression of the pion wave function in the small x and large b regions, b being the impact parameter conjugate to k{sub T}, and improves the applicability of perturbative QCD to hard exclusive processes. The above effect is similar to those from the conventional threshold resummation for the double logarithm ln{sup 2} x and the conventional k{sub T} resummation for ln{sup 2} k{sub T}. Combining the evolution equation for the hard kernel, we are able to organize all large logarithms in the γ{sup ∗}π{sup 0}→γ scattering, and to establish a scheme-independent k{sub T} factorization formula. It will be shown that the significance of next-to-leading-order contributions and saturation behaviors of this process at high energy differ from those under the conventional resummations. It implies that QCD logarithmic corrections to a process must be handled appropriately, before its data are used to extract a hadron wave function. Our predictions for the involved pion transition form factor, derived under the joint resummation and the input of a non-asymptotic pion wave function with the second Gegenbauer moment a{sub 2}=0.05, match reasonably well the CLEO, BaBar, and Belle data.

  9. Perturbative Pions in Effective Field Theory for Nucleon Interactions

    Science.gov (United States)

    Mehen, Thomas

    2001-12-01

    I discuss pions in effective field theory (EFT) for the nucleon interaction within the power counting scheme proposed by Kaplan-Savage-Wise (KSW). After explaining why KSW power counting demands perturbative treatment of pions, I present results of next-to-next-to-leading order (NNLO) calculations of nucleon-nucleon scattering in S-,P-, and D-wave channels. Perturbative treatment of pions fails in spin-triplet channels. The origin of large perturbative corrections is the piece of the spin-tensor force which survives in the chiral limit.

  10. Single pion production in neutrino-nucleon interactions

    Science.gov (United States)

    Kabirnezhad, M.

    2018-01-01

    This work represents an extension of the single pion production model proposed by Rein [Z. Phys. C 35, 43 (1987)., 10.1007/BF01561054]. The model consists of resonant pion production and nonresonant background contributions coming from three Born diagrams in the helicity basis. The new work includes lepton mass effects, and nonresonance interaction is described by five diagrams based on a nonlinear σ model. This work provides a full kinematic description of single pion production in the neutrino-nucleon interactions, including resonant and nonresonant interactions in the helicity basis, in order to study the interference effect.

  11. Soft pion theorem, asymptotic symmetry and new memory effect

    Science.gov (United States)

    Hamada, Yuta; Sugishita, Sotaro

    2017-11-01

    It is known that soft photon and graviton theorems can be regarded as the Ward-Takahashi identities of asymptotic symmetries. In this paper, we consider soft theorem for pions, i.e., Nambu-Goldstone bosons associated with a spontaneously broken axial symmetry. The soft pion theorem is written as the Ward-Takahashi identities of the S-matrix under asymptotic transformations. We investigate the asymptotic dynamics, and find that the conservation of charges generating the asymptotic transformations can be interpreted as a pion memory effect.

  12. In-medium pion valence distributions in a light-front model

    Energy Technology Data Exchange (ETDEWEB)

    Melo, J.P.B.C. de, E-mail: joao.mello@cruzeirodosul.edu.br [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Tsushima, K. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Ahmed, I. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); National Center for Physics, Quaidi-i-Azam University Campus, Islamabad 45320 (Pakistan)

    2017-03-10

    Pion valence distributions in nuclear medium and vacuum are studied in a light-front constituent quark model. The in-medium input for studying the pion properties is calculated by the quark-meson coupling model. We find that the in-medium pion valence distribution, as well as the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.

  13. Low energy pion production by 400 to 500 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.; Beer, G.; Mason, G.R.; Mathie, E.; Olin, A.; Robertson, L.P.; Vincent, J.S.

    1976-01-01

    Using TRIUMF proton beams of 400- to 500-MeV bombarding carbon and copper targets we have measured positive pion production cross sections for pion energies 20 to 100 MeV and pion angles 60 to 150/sup 0/. The pions were stopped in a range telescope in which time-of-flight, energy loss, and the detection of the pion decay were used for particle identification.

  14. Pion and an improved static bag model

    Energy Technology Data Exchange (ETDEWEB)

    Donoghue, J.F.; Johnson, K.

    1980-04-01

    Quark-model calculations involve an extended static object localized in space. We introduce new methods, involving momentum-space wave packets, which account for this localization. These methods have little effect on heavy states, whose sizes are large compared to their Compton size 1/m, but are very important for light particles such as the pion. In this treatment the pion's mass is naturally very small, and, in order to connect with a spontaneously broken chiral symmetry, we require that m/sub ..pi../ vanish when the light quarks are massless. Expanding about this limit (and also readjusting the fit to other hadrons), we obtain m/sub q/=(m-italic/sub u/+m/sub d/)/2=33 MeV. We calculate F/sub ..pi../ approx. = 145 MeV (using a normalization such that F/sub ..pi../ vertical-bar /sub exp/=93 MeV), F/sub K//F/sub ..pi../ approx. = 1, and various corrections to static properties of baryons. In addition we explore the relationship of our methods with chiral perturbation theory, deriving the formula m/sub ..pi../ /sup 2/=(m-italic/sub u/+m/sub d/) < ..pi..(p) vertical-bar q-bar(0)q(0) vertical-bar ..pi..(p) > in the appropriate approximation and commenting on the quark mass obtained from the nucleon's sigma term. Finally we discuss the bag model's use of the scalar density q-barq as an order parameter describing the separation of the spontaneously broken vacuum phase from the perturbative vacuum of the bag's interior.

  15. Deeply virtual compton scattering on a virtual pion target

    Energy Technology Data Exchange (ETDEWEB)

    Amrath, D.; Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lansberg, J.P. [Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique]|[Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik

    2008-07-15

    We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations. (orig.)

  16. Amplitude analysis of resonant production in three pions

    Energy Technology Data Exchange (ETDEWEB)

    Jackura, Andrew [Indiana Univ., Bloomington, IN (United States); Mikhasenko, Mikhail [Univ. of Bonn (Germany); Szczepaniak, Adam [Indiana Univ., Bloomington, IN (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-11-29

    We present some results on the analysis of three pion resonances. The analyses are motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. We construct reaction amplitudes that satisfy fundamental $S$-matrix principles, which allows the use of models that have physical constraints to be used in fitting data. The models are motivated by the isobar model that satisfy unitarity constraints. The model consist of a Deck production amplitude with which final state interactions are constrained by unitarity. We employ the isobar model where two of the pions form a quasi-stable particle. The analysis is performed in the high-energy, single Regge limit. We specifically discuss the examples of the three pion $J^{PC}=2^{-+}$ resonance in the $\\rho\\pi$ and $f_2\\pi$ channels.

  17. Amplitude analysis of resonant production in three pions

    Science.gov (United States)

    Jackura, Andrew; Mikhasenko, Mikhail; Szczepaniak, Adam

    2016-11-01

    We present some results on the analysis of three pion resonances. The analyses are motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. We construct reaction amplitudes that satisfy fundamental S -matrix principles, which allows the use of models that have physical constraints to be used in fitting data. The models are motivated by the isobar model that satisfy unitarity constraints. The model consist of a Deck production amplitude with which final state interactions are constrained by unitarity. We employ the isobar model where two of the pions form a quasi-stable particle. The analysis is performed in the high-energy, single Regge limit. We specifically discuss the examples of the three pion JPC = 2-+ resonance in the ρπ and f2π channels.

  18. Di-photon resonance and Dark Matter as heavy pions

    CERN Document Server

    Redi, Michele; Tesi, Andrea; Vigiani, Elena

    2016-01-01

    We analyse confining gauge theories where the 750 GeV di-photon resonance is a composite techni-pion that undergoes anomalous decays into SM vectors. These scenarios naturally contain accidentally stable techni-pions Dark Matter candidates. The di-photon resonance can acquire a larger width by decaying into Dark Matter through the CP-violating $\\theta$-term of the new gauge theory reproducing the cosmological Dark Matter density as thermal relic.

  19. The transverse spin structure of the pion at short distances

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Szymanowski, Lech [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Ecole Polytechnique, CNRS, Palaiseau (France). Centre de Physique Theorique; Paris-Sud Univ., CNRS, Orsay (France). Lab. de Physique Theorique

    2010-03-15

    We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q{sup 2}. It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions from the end-point regions of the longitudinal quark momenta in the pion. We derive simple analytic expressions for the dominant terms at high Q{sup 2} and illustrate them numerically. (orig.)

  20. The transverse spin structure of the pion at short distances

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus, E-mail: mdiehl@mail.desy.d [Deutsches Elektronen-Synchroton DESY, 22603 Hamburg (Germany); Szymanowski, Lech [Soltan Institute for Nuclear Studies, Warsaw (Poland); Centre de Physique Theorique, Ecole Polytechnique, CNRS, 91128 Palaiseau (France); Laboratoire de Physique Theorique, Universite Paris-Sud, CNRS, 91405 Orsay (France)

    2010-06-14

    We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q{sup 2}. It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions from the end-point regions of the longitudinal quark momenta in the pion. We derive simple analytic expressions for the dominant terms at high Q{sup 2} and illustrate them numerically.

  1. The Onset of Quark-Hadron Duality in Pion Electroproduction

    Energy Technology Data Exchange (ETDEWEB)

    Tigran Navasardyan; Gary Adams; Abdellah Ahmidouch; Tatiana Angelescu; John Arrington; Razmik Asaturyan; O. Baker; Nawal Benmouna; Crystal Bertoncini; Henk Blok; Werner Boeglin; Peter Bosted; Herbert Breuer; Michael Christy; Simon Connell; Yonggang Cui; Mark Dalton; Samuel Danagoulian; Donal Day; T. Dodario; James Dunne; Dipangkar Dutta; Najib Elkhayari; Rolf Ent; Howard Fenker; Valera Frolov; Liping Gan; David Gaskell; Kawtar Hafidi; Wendy Hinton; Roy Holt; Tanja Horn; Garth Huber; Ed Hungerford; Xiaodong Jiang; Mark Jones; Kyungseon Joo; Narbe Kalantarians; James Kelly; Cynthia Keppel; Edward Kinney; V. Kubarovski; Ya Li; Yongguang Liang; Simona Malace; Pete Markowitz; Erin McGrath; Daniella Mckee; David Meekins; Hamlet Mkrtchyan; Brian Moziak; Gabriel Niculescu; Maria-Ioana Niculescu; Allena Opper; Tanya Ostapenko; Paul Reimer; Joerg Reinhold; Julie Roche; Stephen Rock; Elaine Schulte; Edwin Segbefia; C. Smith; G.R. Smith; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Maurizio Ungaro; Alicia Uzzle; Sandra Vidakovic; Anthony Villano; William Vulcan; Miao Wang; Glen Warren; Frank Wesselmann; Bogdan Wojtsekhowski; Stephen Wood; Chuncheng Xu; Lulin Yuan; Xiaochao Zheng; Hong Guo Zhu

    2006-08-29

    A large data set of charged-pion electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-to- pion production mechanisms.

  2. Finite size effects of a pion matrix element

    Energy Technology Data Exchange (ETDEWEB)

    Guagnelli, M. [Dipartimento di Fisica, Universita di Roma Tor Vergata and INFN, Sezione di Roma II, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Jansen, K. [NIC/DESY Zeuthen, Platanenallee 6, D-15738 Zeuthen (Germany); Palombi, F. [Dipartimento di Fisica, Universita di Roma Tor Vergata and INFN, Sezione di Roma II, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); E. Fermi Research Center, c/o Compendio Viminale, pal. F, I-00184 Rome (Italy); Petronzio, R. [Dipartimento di Fisica, Universita di Roma Tor Vergata and INFN, Sezione di Roma II, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Shindler, A. [NIC/DESY Zeuthen, Platanenallee 6, D-15738 Zeuthen (Germany); Wetzorke, I. [NIC/DESY Zeuthen, Platanenallee 6, D-15738 Zeuthen (Germany)]. E-mail: ines.wetzorke@desy.de

    2004-09-09

    We investigate finite size effects of the pion matrix element of the non-singlet, twist-2 operator corresponding to the average momentum of non-singlet quark densities. Using the quenched approximation, they come out to be surprisingly large when compared to the finite size effects of the pion mass. As a consequence, simulations of corresponding nucleon matrix elements could be affected by finite size effects even stronger which could lead to serious systematic uncertainties in their evaluation.

  3. Di-photon resonance and Dark Matter as heavy pions

    Energy Technology Data Exchange (ETDEWEB)

    Redi, Michele [INFN, Sezione di Firenze,Via G. Sansone, 1, I-50019 Sesto Fiorentino (Italy); Strumia, Alessandro [Dipartimento di Fisica dell’Università di Pisa and INFN,Pisa (Italy); Theory Division, CERN,Geneva (Switzerland); Tesi, Andrea [Enrico Fermi Institute, University of Chicago,Chicago, IL 60637 (United States); Vigiani, Elena [Dipartimento di Fisica dell’Università di Pisa and INFN,Pisa (Italy)

    2016-05-13

    We analyse confining gauge theories where the 750 GeV di-photon resonance is a composite techni-pion that undergoes anomalous decays into SM vectors. These scenarios naturally contain accidentally stable techni-pions Dark Matter candidates. The di-photon resonance can acquire a larger width by decaying into Dark Matter through the CP-violating θ-term of the new gauge theory reproducing the cosmological Dark Matter density as a thermal relic.

  4. Measurements of observables in the pion-nucleon system, nuclear a- dependence of heavy quark production and rare decays of D and B mesons. Progress report, 1 December, 1990--15 February, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sadler, M.E.; Isenhower, L.D.

    1992-02-15

    This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments. (LSP)

  5. Gravitational wave from dark sector with dark pion

    Science.gov (United States)

    Tsumura, Koji; Yamada, Masatoshi; Yamaguchi, Yuya

    2017-07-01

    In this work, we investigate the spectra of gravitational waves produced by chiral symmetry breaking in dark quantum chromodynamics (dQCD) sector. The dark pion (π) can be a dark matter candidate as weakly interacting massive particle (WIMP) or strongly interacting massive particle (SIMP). For a WIMP scenario, we introduce the dQCD sector coupled to the standard model (SM) sector with classical scale invariance and investigate the annihilation process of the dark pion via the 2π → 2 SM process. For a SIMP scenario, we investigate the 3π → 2π annihilation process of the dark pion as a SIMP using chiral perturbation theory. We find that in the WIMP scenario the gravitational wave background spectra can be observed by future space gravitational wave antennas. On the other hand, when the dark pion is the SIMP dark matter with the constraints for the chiral perturbative limit and pion-pion scattering cross section, the chiral phase transition becomes crossover and then the gravitational waves are not produced.

  6. Information on the pion distribution amplitude from the pion-photon transition form factor with the Belle and BABAR data

    Science.gov (United States)

    Wu, Xing-Gang; Huang, Tao; Zhong, Tao

    2013-06-01

    We perform an analysis of all existing experimental data on the pion-photon transition form factor (TFF). In the calculation, we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF's limiting behavior at both Q2 → 0 and Q2 → ∞. At present, the pion distribution amplitude (DA) is not definitely determined, it is helpful to have a pion DA model that can mimic all the behaviors suggested in the literature. For the purpose, we adopt the conventional model for pion wavefunction/DA whose broadness is dominantly controlled by a single parameter B. We fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within small Q2 region (Q2 <= 15 GeV2), where all the data are consistent with each other. The pion-photon TFF is then extrapolated into a larger Q2 region. It is found that we still need more data at a large Q2 region in order to determine the precise value of B, and we hope that the definite behavior of pion DA can be concluded finally by the consistent data in the coming future.

  7. Inclusive pion and η production in p+Nb collisions at 3.5 GeV beam energy

    Science.gov (United States)

    Agakishiev, G.; Balanda, A.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Chernenko, S.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Göbel, K.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kornakov, G.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Ladygin, V.; Lalik, R.; Lang, S.; Lapidus, K.; Lebedev, A.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Müntz, C.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.

    2013-08-01

    Data on inclusive pion and η production measured with the dielectron spectrometer HADES in the reaction p+93Nb at a kinetic beam energy of 3.5 GeV are presented. Our results, obtained with the photon-conversion method, supplement the rather sparse information on neutral-meson production in proton-nucleus reactions existing for this bombarding energy regime. The reconstructed e+e-e+e- transverse-momentum and rapidity distributions are confronted with transport-model calculations, which account fairly well for both π0 and η production.

  8. Pion Form Factor in Chiral Limit of Hard-Wall AdS/QCD Model

    Energy Technology Data Exchange (ETDEWEB)

    Anatoly Radyushkin; Hovhannes Grigoryan

    2007-12-01

    We develop a formalism to calculate form factor and charge density distribution of pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic expressions for these functions and for the pion form factor. They allow to relate such observables as the pion decay constant and the pion charge electric radius to the values of chiral condensate and hard-wall cutoff scale. The evolution of the pion form factor to large values of the momentum transfer is discussed, and results are compared to existing experimental data.

  9. Are You Neutral About Net Neutrality

    Science.gov (United States)

    2007-06-20

    Information Resources Management College National Defense University Are You Neutral About Net Neutrality ? A presentation for Systems & Software...author uses Verizon FiOS for phone, TV, and internet service 3 Agenda Net Neutrality —Through 2 Lenses Who Are the Players & What Are They Saying...Medical Treatment Mini-Case Studies Updates Closing Thoughts 4 Working Definitions of Net Neutrality "Network Neutrality" is the concept that

  10. Gauge invariance and the electromagnetic current of composite pions

    Energy Technology Data Exchange (ETDEWEB)

    Frank, M.R. [Hampton Univ., VA (United States). Dept. of Physics]|[Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Tandy, P.C. [Kent State Univ., OH (United States). Center for Nuclear Research

    1993-03-24

    The Global Color-symmetry Model of QCD is extended to deal with a background electromagnetic field, and the associated conserved current is identified for the finite size {bar q}q pion modes at tree level. A well-defined truncation issued that factorizes the bilocal pion field into a local field variable and a hadronic form factor having a ladder Bethe-Salpeter content. The associated pion charge form factor is formulated. These developments are used to provide an illustration of how an effective hadronic action containing form factors may be electromagnetically coupled in a gauge invariant way that is accountable to its field substructure. In particular, the Ward-Takahashi identity for the photon vertex appropriate to the localized pion fields is seen to contain the hadronic form factors. In this context, gauge invariance of the effective hadronic action also requires recognition of the fact that the free inverse propagator for the localized pion field gauge transforms due to the substructure field content that has been absorbed into it.

  11. Charged Pion Energy Reconstruction in the ATLAS Barrel Calorimeter

    CERN Document Server

    Bosman, Martine; Nessi, Marzio

    1999-01-01

    Intrinsic performance of the ATLAS calorimeters in the barrel region with respect to charged pions was studied. For this the following simulated data were used: pion energy scans ($E = 20, 50, 200, 400$ and $1000$ GeV) at two pseudo-rapidity points ($eta = 0.3$ and $1.3$) and pseudo-rapidity scans ($-0.2 < eta < 1.8$) with pions of constant transverse energy ($E_T = 20$ and $50$ GeV). For pion energy reconstruction the benchmark approach was used. Performance was estimated for cases, when energy and rapidity dependent and independent calibration parameters were applied. The best results were obtained with energy and rapidity dependent parameters. Studies done for pions enabled optimization of the cone size and of the cut to obtain the best energy resolution. Energy dependence of the resolution can be parameterized as: $(50pm4)%/sqrt{E} oplus (3.4pm0.3)% oplus 1.0/E$ at $eta = 0.3$ and $(68pm8)%/sqrt{E} oplus (3.0pm0.7)% oplus 1.5/E$ at $eta = 1.3$. Larger constant term at $eta=0.3$ can be explained by l...

  12. Sketching the pion's valence-quark generalised parton distribution

    Directory of Open Access Journals (Sweden)

    C. Mezrag

    2015-02-01

    Full Text Available In order to learn effectively from measurements of generalised parton distributions (GPDs, it is desirable to compute them using a framework that can potentially connect empirical information with basic features of the Standard Model. We sketch an approach to such computations, based upon a rainbow-ladder (RL truncation of QCD's Dyson–Schwinger equations and exemplified via the pion's valence dressed-quark GPD, Hπv(x,ξ,t. Our analysis focuses primarily on ξ=0, although we also capitalise on the symmetry-preserving nature of the RL truncation by connecting Hπv(x,ξ=±1,t with the pion's valence-quark parton distribution amplitude. We explain that the impulse-approximation used hitherto to define the pion's valence dressed-quark GPD is generally invalid owing to omission of contributions from the gluons which bind dressed-quarks into the pion. A simple correction enables us to identify a practicable improvement to the approximation for Hπv(x,0,t, expressed as the Radon transform of a single amplitude. Therewith we obtain results for Hπv(x,0,t and the associated impact-parameter dependent distribution, qπv(x,|b→⊥|, which provide a qualitatively sound picture of the pion's dressed-quark structure at a hadronic scale. We evolve the distributions to a scale ζ=2 GeV, so as to facilitate comparisons in future with results from experiment or other nonperturbative methods.

  13. Basic features of the pion valence-quark distribution function

    Directory of Open Access Journals (Sweden)

    Lei Chang

    2014-10-01

    Full Text Available The impulse-approximation expression used hitherto to define the pion's valence-quark distribution function is flawed because it omits contributions from the gluons which bind quarks into the pion. A corrected leading-order expression produces the model-independent result that quarks dressed via the rainbow–ladder truncation, or any practical analogue, carry all the pion's light-front momentum at a characteristic hadronic scale. Corrections to the leading contribution may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we use an algebraic model to express the principal impact of both classes of corrections. This enables a realistic comparison with experiment that allows us to highlight the basic features of the pion's measurable valence-quark distribution, qπ(x; namely, at a characteristic hadronic scale, qπ(x∼(1−x2 for x≳0.85; and the valence-quarks carry approximately two-thirds of the pion's light-front momentum.

  14. Search for Antineutrino Charged Current Coherent Pion Production at SciBooNE

    CERN Document Server

    Tanaka, Hide-Kazu

    2009-01-01

    The SciBooNE experiment (Fermilab) recently published results of a search for charged current coherent pion production in neutrino mode: muon neutrinos scattering on carbon. The results of this study are that no evidence for coherent pion production is observed, and SciBooNE set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section. Recently proposed new coherent pion models predict a production of charged current coherent pion events just below the SciBooNE's upper limit. Motivated by this, we performed a search for charged current coherent pion production using SciBooNE's collected antineutrino data since antineutrino data are expected to be more sensitive to look at coherent pion production than neutrino data. This paper describes preliminary results of a search for antineutrino charged current coherent pion production at the SciBooNE experiment.

  15. Pions as collective modes in the glueball condensate vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, T.H.; Zahed, I.

    1987-07-01

    The glueball condensate vacuum model is extended to incorporate the effects of light quarks. The resulting model exhibits spontaneous breaking of chiral SU(2)/sub f/ symmetry, and has a new kind of collective excitations, pions, which are distinct from the usual bag-model-type states. The dynamics of the pions are described by a sigma model, and the parameters and f/sub ..pi../ are calculated in terms of the radius R of the vacuum cells. The pion mass is related to and m/sub q/ via the usual partial conservation of axial-vector current relation. The model is extended to broken SU(3)/sub f/ using lowest-order chiral perturbation theory, and a mass formula for the eta' meson is obtained by including effects of the axial anomaly.

  16. Measurement of the charged pion polarizability at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, Thiemo Christian Ingo

    2012-09-26

    The reaction {pi}{sup -}+Z{yields}{pi}{sup -}+{gamma}+Z in which a photon is produced by a beam pion scattering off a quasi-real photon of the Coulomb field of the target nucleus is identified experimentally by the tiny magnitude of the momentum transfer to the nucleus. This process gives access to the charged pion polarizabilities {alpha}{sub {pi}} and {beta}{sub {pi}} whose experimental determination constitutes an important test of Chiral Perturbation Theory. In this work, the pion polarizability is obtained as {alpha}{sub {pi}}=(1.9{+-}0.7{sub stat.}{+-}0.8{sub syst.}) x 10{sup -4} fm{sup 3} from data taken with 190 GeV/c hadron beam provided by SPS to the COMPASS experiment at CERN in November 2009 and under the assumption of {alpha}{sub {pi}}+{beta}{sub {pi}}=0.

  17. Chiral symmetry in pion-quark interactions: a first study

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, C.M.; Robilotta, M.R. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1995-12-31

    In the study of nuclear processes we learn that chiral symmetry is an important symmetry for systems with pions. The works of Weinberg have shown that effective Lagrangians can be used to reproduce current algebra results, with advantage of allowing simpler calculations for processes with several pions. In the case of nucleon-nucleon interactions processes with range less than 1 fm require the use of phenomenological models with quark degrees of freedom. This approach avoids in hadron physics, the problem of the very strong effective coupling constant of QCD in this region. One believes that chiral symmetry plays an important role in hadron physics. The purpose of this work is to study how this symmetry works when one connects pions with constituents quarks. (author) 3 refs., 1 fig.

  18. Isospin Violation in Threshold Pion-Nucleon Scattering

    CERN Document Server

    Ericson, Torleif Eric Oskar

    2005-01-01

    We discuss the electromagnetic corrections to the pion-nucleon scattering lengths generated by minimal e. m. coupling from a knowledge of the low energy expansion of the pion-nucleon elastic scattering amplitude as well as from the nucleon and delta pole terms, all a consequence of purely strong interactions. We assume the heavy baryon limit; the e.m. and axial form factors and the masses are used with their empirical values, such that there is no free parameter. The different terms have a clear physical and intuitive origin. In particular, a large isospin breaking contribution to the isoscalar term appears for the elastic charged-pion scattering lengths. We attempt a comparison to the results from chiral effective field theory (EFT) with a physical interpretation of the empirical constants in that approach. The results are applied to the energy shift and width of pionic hydrogen.

  19. One-pion production in neutrino-nucleus collisions

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, E. [Departamento de Física Fundamental e IUFFyM, Universidad de Salamanca, E-37008 Salamanca (Spain); Nieves, J. [Instituto de Física Corpuscular (IFIC), Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigación de Paterna, Apartado 22085, E-46071 Valencia (Spain); Vicente-Vacas, J. M. [Departamento de Física Teórica e IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Apartado 22085, E-46071 Valencia (Spain)

    2015-05-15

    We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by the inclusion of new resonant contributions in the production process. Our results are compared with recent MiniBooNE data measured in mineral oil. Our total cross sections are below data for neutrino energies above ≈ 1 GeV. As with other theoretical calculations, the agreement with data improves if we neglect pion final state interaction. This is also the case for differential cross sections convoluted over the neutrino flux.

  20. Subthreshold Pion Production from Characterized Events in NEON-20 + ALUMINUM-27 Reactions

    Science.gov (United States)

    Hannuschke, Stefan Andreas

    The production of positively charged pions below the free nucleon-nucleon threshold in intermediate energy heavy ion collisions was investigated. The system studied was ^{20}Ne + ^{27}Al at bombarding energies of 90, 110 and 150 AMeV. Pions and fragments were detected using the MSU 4pi Array yielding complete event characterization. Using the Array to determine the centrality of pion producing events, an apparent enhancement of the production cross section for peripheral events was found. That trend increases with decreasing bombarding energy. The kinetic energy distributions measured for protons and pions are in good agreement with BUU model calculations. The proton spectra are reproduced for all kinetic energies, whereas the pion spectra are under-predicted at the lower energies. Analyzing the energy spectra for all detection angles in terms of a classical Maxwell-Boltzmann distribution, the apparent temperatures for protons and pions were extracted. The values for both, pions and protons, are in very good agreement with known systematics. The pion temperatures show no dependence on the event centrality, whereas the ones for proton emission show a steady decrease with increasing impact parameter. Correlations of pions with the event as a whole were also investigated. The azimuthal distribution with respect to the reaction plane shows a weak in-plane emission for pions in the forward direction. A transverse flow analysis for pions and light charged particles shows the typical signal for helium and protons. The pions show an enhancement for forward rapidities at the highest beam energy.

  1. Exclusive near threshold two-pion production with the MOMO experiment at COSY

    Science.gov (United States)

    Bavink, S.; Bellemann, F.; Berg, A.; Bisplinghoff, J.; Bohlscheid, G.; Ernst, J.; Henrich, C.; Hinterberger, F.; Ibald, R.; Jahn, R.; Jarczyk, L.; Joosten, R.; Kozela, A.; Machner, H.; Magiera, A.; Maschuw, R.; Mayer-Kuckuk, T.; Mertler, G.; Munkel, J.; Neumann-Cosel, P. v.; Rosendaal, D.; Rossen, P. v.; Schnitker, H.; Scho, K.; Smyrski, J.; Strzalkowski, A.; Tölle, R.; Wurzinger, R.

    1998-03-01

    Near threshold two pion production via the reaction pd → 3Heπ +π - was measured kinematically complete with the MOMO experiment at COSY. A remarkable deviation of the obtained two pion invariant mass spectra from phase space as well as a predominant back to back and sidewise emission of the two pions was observed.

  2. Virtual-pion and two-photon production in pp scattering

    NARCIS (Netherlands)

    Scholten, O; Korchin, AY

    Two-photon production in pp scattering is proposed as a means of studying virtual-pion emission. Such a process is complementary to real-pion emission in pp scattering. The virtual-pion signal is embedded in a background of double-photon bremsstrahlung. We have developed a model to describe this

  3. Threshold pion electroproduction at large momentum transfers; Threshold Pion-Elektroproduktion bei grossen Energieuebertraegen

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Andreas

    2008-02-15

    We consider pion electroproduction close to threshold for Q{sup 2} in the region 1-10 GeV{sup 2} on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, E{sub 0+} and L{sub 0+}, is calculated in the chiral limit using light-cone sum rules. Predictions for the cross sections in the threshold region are given taking into account P-wave contributions that, as we argue, are model independent to a large extent. The results are compared with the SLAC E136 data on the structure function F{sub 2}(W,Q{sup 2}) in the threshold region. (orig.)

  4. Study of the Production of Single Pions in Pion-proton Collisions near Threshold

    CERN Multimedia

    2002-01-01

    This experiment aims at a complete-kinematics measurement of the processes @p|-p @A @p|-@p|+n and @p|+p @A @p|+@p|+n in the region of incident momenta between 300 MeV/c and 460 MeV/c. It uses the Omicron Spectrometer with detectors placed in the magnetic field close to a 12 atm. hydrogen gas target. The apparatus has an acceptance of 4\\% for the processes to be studied. \\\\ \\\\ Their threshold is at 279 MeV/c and pion production in this region is interesting from the point of view of the determination of transformation properties of the chiral-symmetry-breaking part of the Lagrangian.

  5. Parton coalescence and the antiproton/pion anomaly at RHIC.

    Science.gov (United States)

    Greco, V; Ko, C M; Lévai, P

    2003-05-23

    Coalescence of minijet partons with partons from the quark-gluon plasma formed in relativistic heavy ion collisions is suggested as the mechanism for production of hadrons with intermediate transverse momentum. The resulting enhanced antiproton and pion yields at intermediate transverse momenta give a plausible explanation for the observed large antiproton to pion ratio. With further increasing momentum, the ratio is predicted to decrease and approach the small value given by independent fragmentations of minijet partons after their energy loss in the quark-gluon plasma.

  6. Pion photoproduction on 27Al: The effect of Vopt

    Science.gov (United States)

    Freed, N.; Ostrander, P.

    1981-07-01

    Total cross sections for pion photoproduction to bound states in 27Mg are calculated in the distorted wave impulse approximation and compared to experiment. Particular attention is paid to the form of the optical potential used to incorporate final state effects. Substantial differences are found between results using an earlier potential and present results using potentials having different analytic forms. The latter lead to good agreement with experiment. [NUCLEAR REACTIONS 27Al(γ,π+). Calculated total cross sections; effects of pion optical potential.

  7. New Results for the Charged Pion Electromagnetic Form Factor

    CERN Document Server

    Volmer, J; Anklin, H; Armstrong, C S; Arrington, J; Assamagan, Ketevi A; Avery, S; Baker, O K; Blok, H P; Bochna, C W; Brash, E J; Breuer, H; Chant, N S; Dunne, J; Eden, T; Ent, R; Gaskell, D; Gilman, R; Gustafsson, K K; Hinton, W; Huber, G M; Jackson, H; Jones, M K; Keppel, C E; Kim, P H; Kim, W; Klein, A; Koltenuk, D M; Liang, M; Lolos, G J; Lung, A; Mack, D J; McKee, D; Meekins, D G; Mitchell, J; Mkrtchyan, H G; Müller, B; Niculescu, G; Niculescu, I; Pitz, D; Potterveld, D H; Qin, L M; Reinhold, J; Shin, I K; Stepanyan, S; Tadevosyan, V; Tang, L G; Van der Meer, R L J; Vansyoc, K; Van Westrum, D; Vulcan, W; Wood, S; Yan, C; Zhao, W X; Zihlmann, B

    2001-01-01

    Separated longitudinal and transverse structure functions for the reaction 1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6 (GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parameterization fitted to very low Q2 elastic data.

  8. Neutral Pion Transition Form Factor Measurement and Run Control at the NA62 experiment

    CERN Document Server

    AUTHOR|(CDS)2082375; Goudzovski, Evgueni

    The measurement of the 0 electromagnetic transition form factor (TFF) slope a is performed in the time-like region of momentum transfer using a sample of 1.1 $10^6$ $\\pi^0 \\to e^+ e^- \\gamma$ Dalitz decays collected at the NA62-RK experiment in 2007. The event selection, the fit procedure and the study of the systematic ffects are presented. The final result obtained $a = (3.68 \\pm 0.51stat \\pm 0.25syst) \\times 10^{-2} $ is the most precise to date and represents the first evidence of a non-zero $\\pi^0$ TFF slope with more than 3 $\\sigma$ significance. The NA62 experiment based at the CERN SPS is currently taking data and aims at measuring the branching fraction of the $K \\to \\pi \

  9. Precision Measurements of Neutral Pion Electroproduction Near Threshold: A Test of Chiral QCD Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Richard A. [University of Virginia; Chirapatpimol, Khem [University of Virginia; Smith, Lee Cole [University of Virginia

    2013-08-01

    Preliminary results are presented from an experiment to measure {pi}{sup 0} electroproduction at and above threshold using the p(e;e' p){pi}{sup 0} reaction. The data were taken at a beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time in {pi}{sup 0} threshold electroproduction, complete coverage of the {phi}{sub {pi}}* and {theta}{sub {pi}}* angles in the center-of-mass (C.M.) was obtained for the invariant mass region up to {Delta}W=18 MeV above the {pi}{sup 0} threshold. At the same time our invariant momentum transfer squared covers the range Q{sup 2} = 0.05-0.15 (GeV/c){sup 2} with twelve bins in Q{sup 2}. The improved kinematic coverage in C.M., W and Q{sup 2} will better constrain theoretical interpretations of the data using phenomenological models and QCD-inspired models such as Heavy Baryon Chiral Perturbation Theory.

  10. Measurement of neutrino induced charged current neutral pion production cross section at SciBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Catala-Perez, Juan [Univ. of Valencia (Spain)

    2014-01-01

    SciBooNE is a neutrino scattering experiment located in the Booster Neutrino Beam at Fermilab. It collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon around 1 GeV neutrino energy. In this thesis we present the results on the measurement of the muon neutrino cross section resulting in a μ- plus a single π0 final state (CC- π0 channel). The present work will show the steps taken to achieve this result: from the reconstruction improvements to the background extraction. The flux-averaged CC - π0 production cross section measurement obtained in this thesis < σCC- π0 > Φ = (5.6 ± 1.9fit ± 0.7beam ± 0.5int - 0.7det) × 10-40 cm2/N at an average energy of 0.89 GeV is found to agree well both with the expectation from the Monte Ca

  11. Neutral Pion and Direct Photon Production in the SPS Energy Regime

    CERN Document Server

    Baumann, Christoph

    The search for the quark-gluon plasma (QGP) has been the major driving force behind research activities in the field of ultra-relativisic heavy-ion physics in the last decades. Since the start of the experimental program at the BNL-AGS, pursuit of such extreme states of matter have been the focus of many experiments. The predicted deconfinement of quarks and gluons is not only of interest with respect to the Standard Model of Particle Physics, it is also relevant for cosmology. Current models assume that the universe was filled with a quark-gluon plasma shortly after the Big Bang. Experimental results from heavy-ion experiments can help to refine the understanding of the early phase of the cosmos. A first milestone in the search for the QGP was the CERN press release in 2000, announcing the discovery of a hot and dense state of matter bearing many properties of the predicted QGP. In 2005, the four major RHIC experiments jointly announced the creation of an extreme state of matter, similar to the predicted QGP...

  12. Neutral Pion Electroproduction in the Resonance Region at High $Q^2$

    CERN Document Server

    Villano, A N; Bosted, P E; Connell, S H; Dalton, M M; Jones, M K; Adams, G S; Afanasev, A; Ahmidouch, A; Angelescu, T; Arrington, J; Asaturyan, R; Baker, O K; Benmouna, N; Berman, B L; Breuer, H; Christy, M E; Cui, Y; Danagulyan, S; Day, D; Dodario, T; Dunne, J A; Dutta, D; Khayari, N El; Elliot, B; Ent, R; Fenker, H C; Frolov, V V; Gan, L; Gaskell, D; Gasparian, A; Grullon, S; Hafidi, K; Hinton, W; Holt, R J; Horn, T; Huber, G M; Hungerford, E; Joo, K; Kalantarians, N; Keppel, C E; Kinney, E R; Kubarovski, V; Li, Y; Liang, Y; Lu, M; Lung, A; Mack, D; Malace, S; Markowitz, P; McKee, P; Meekins, D G; Mkrtchyan, H; Napolitano, J; Niculescu, G; Niculescu, I; Opper, A K; Pamela, P; Potterveld, D H; Reimer, Paul E; Reinhold, J; Roche, J; Rock, S E; Schulte, E; Segbefia, E; Smith, C; Smith, G R; Stepanyan, S; Tadevosyan, V; Tahani, A; Tang, L; Tvaskis, V; Ungaro, M; Uzzle, A; Vidakovic, S; Vulcan, W F; Wang, M; Warren, G; Wesselmann, F R; Wojtsekhowski, B; Wood, S A; Xu, C; Yuan, L; Zheng, X; Zhu, H

    2009-01-01

    The process $ep \\to e^{\\prime}p^{\\prime}\\pi^0$ has been measured at $Q^2$ = 6.4 and 7.7 \\ufourmomts in Jefferson Lab's Hall C. Unpolarized differential cross sections are reported in the virtual photon-proton center of mass frame considering the process $\\gamma^{\\ast}p \\to p^{\\prime}\\pi^0$. Various details relating to the background subtractions, radiative corrections and systematic errors are discussed. The usefulness of the data with regard to the measurement of the electromagnetic properties of the well known $\\Delta(1232)$ resonance is covered in detail. Specifically considered are the electromagnetic and scalar-magnetic ratios $R_{EM}$ and $R_{SM}$ along with the magnetic transition form factor $G_M^{\\ast}$. It is found that the rapid fall off of the $\\Delta(1232)$ contribution continues into this region of momentum transfer and that other resonances

  13. Decays of neutral pions: Electromagnetic transition form factor and radiative corrections

    Directory of Open Access Journals (Sweden)

    Husek Tomáš

    2017-01-01

    Full Text Available We briefly summarize experimental and theoretical results on the rare decay π0 → e+e−. The notorious 3.3σ discrepancy between the Standard Model prediction and the experimental value provided by KTeV collaboration is discussed in the view of a complete set of next-to-leading-order QED radiative corrections. We also present the Two-Hadron Saturation (THS scenario for the PVV correlator and apply it to the decay under discussion. The discrepancy under discussion then reduces down to 1.8σ. Finally, we turn our attention the the Dalitz decay π0 → e+e−γ. We have recalculated the Mikaelian and Smith radiative corrections beyond the soft-photon approximation, i.e. over the whole range of the Dalitz plot and with no restrictions on the radiative photon. In contrast to the previous calculations, we also included the one-photon irreducible contribution at one-loop level. Our results can be also used for a further treatment of the processes with heavier particles in the final state.

  14. Page 1 Ratio of Pions to Protons & Neutral to Charged Interacting ...

    Indian Academy of Sciences (India)

    Cervasi et al. and Khrimian used arrays of GM counters alone; Gottlieb,. Deutschmann and Lal et al. have used multiplate cloud chambers. In all experiments in which visual detectors like nuclear emulsions or cloud chambers have not been used, it must be emphasised that the identi- fication of both the charge and the ...

  15. Emission patterns of neutral pions in 40A MeV Ta plus Au reactions

    Czech Academy of Sciences Publication Activity Database

    Piasecki, K.; Matulewicz, T.; Yahlali, N.; Delagrange, H.; Díaz, J.; d'Enterria, D.G.; Fernández, F.; Kugler, Andrej; Lohner, H.; Martinez-Garcia, G.; Ostendorf, R. W.; Schutz, Y.; Tlustý, Pavel; Turrisi, R.; Wagner, Vladimír; Wilschut, H. W.

    2010-01-01

    Roč. 81, č. 5 (2010), 054912/1-054912/7 ISSN 0556-2813 Institutional research plan: CEZ:AV0Z10480505 Keywords : HEAVY-ION COLLISIONS * SEGMENTED ELECTROMAGNETIC CALORIMETER * NUCLEAR-MATTER Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.416, year: 2010

  16. Measurement of the pion electromagnetic form-factor in the SELEX experiment

    Energy Technology Data Exchange (ETDEWEB)

    Dirkes, Guido; /Heidelberg, Max Planck Inst.

    1999-10-01

    This work describes the analysis of pion-electron scattering data of the fix-trage-experiment SELEX at Fermilab with special respects to the pion charge radius. At an average rate of 150 Hz, 215 million candidates for pion-electron elastic scattering were recorded during the fix target run until September 1997. A sample of 24,000 pion-electron scattering events was extracted in the course of several data strips. Monte Carlo studies gave detailed knowledge of acceptance, which is important due to special trigger conditions. Systematics were studied and the pion mean square charge radius was determined.

  17. Longitudinal Lelectroproduction of Charged Pions on Hydrogen, Deuterium, and Helium 3

    Energy Technology Data Exchange (ETDEWEB)

    Gaskell, David [Oregon State Univ., Corvallis, OR (United States)

    2001-03-22

    Conventional pictures of nuclear interactions, in which the pion mediates the long/medium range part of the nuclear force, predict an enhancement of the virtual pion cloud in nuclei relative to that in the free nucleon. Jefferson Lab Experiment E91003 measured charged pion electroproduction from Hydrogen, Deuterium, and Helium-3. The longitudinal cross section, which in the limit of pole dominance can be viewed as the quasifree knockout of a virtual pion, was extracted via a Rosenbluth separation. The longitudinal cross sections from Deuterium and Helium-3 were compared to Hydrogen to look for signatures of the nuclear pions.

  18. Pion Condensation by Rotation in a Magnetic Field

    Science.gov (United States)

    Liu, Yizhuang; Zahed, Ismail

    2018-01-01

    We show that the combined effects of a rotation plus a magnetic field can cause charged pion condensation. We suggest that this phenomenon may yield to observable effects in current heavy ion collisions at collider energies, where large magnetism and rotations are expected in off-central collisions.

  19. Quantitative assessment of target dependence of pion fluctuation in ...

    Indian Academy of Sciences (India)

    Quantitative assessment of target dependence of pion fluctuation in hadronic interactions – estimation through erraticity. DIPAK GHOSH1, ARGHA DEB1, MITALI MONDAL2,∗,. ARINDAM MONDAL3 and SITARAM PAL4. 1Nuclear and Particle Physics Research Centre, Department of Physics,. Jadavpur University, Kolkata ...

  20. Dynamical pions and kaons in the glueball condensate vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, T.H.; Klabuar, D.; Zahed, I.

    1987-07-01

    The model for pions as collective modes in the glueball condensate vacuum is extended to incorporate time-independent fields and massive quarks. The quark mass dependence of and f/sub K/ is calculated without resorting to chiral perturbation theory. Alternative schemes for introducing time dependence are discussed and our model is compared to potential-type models.

  1. Measurement of the pion form factor at higher energies

    Energy Technology Data Exchange (ETDEWEB)

    Mack, D.J. [CEBAF, Newport News, VA (United States)

    1994-04-01

    One of the strongest arguments for increasing the nominal CEBAF beam energy to equal or exceed 6 GeV is that one would be able to make quality high Q{sup 2} measurements of the charged pion form factor.

  2. Probability of pion absorption by. cap alpha. -cluster in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, F. (Heidelberg Univ. (Germany, F.R.). Inst. fuer Theoretische Physik; Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.))

    1982-07-08

    A multistep direct reaction model with pickup is extended to describe the formation of tritons and /sup 3/He-particles in nucleon- and pion-induced precompound reactions. In the latter ones, those tritons not accounted for by pickup can be explained as primary ones from absorption by ..cap alpha..-clusters, for which a 10% probability is deduced.

  3. Massive pions, anomalies and baryons in holographic QCD

    Energy Technology Data Exchange (ETDEWEB)

    Domenech, O. [Departament de Fisica and IFAE, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Panico, G., E-mail: panico@phys.ethz.c [Institute for Theoretical Physics, ETH Zurich, 8093 Zurich (Switzerland); Wulzer, A. [Institut de Theorie des Phenomenes Physiques, EPFL, CH-1015 Lausanne (Switzerland)

    2011-03-01

    We consider a holographic model of QCD, obtained by a very simple modification of the original construction, which describes at the same time the pion mass, the QCD anomalies and the baryons as topological solitons. We study in detail its phenomenological implications in both the mesonic and baryonic sectors and compare with the observations.

  4. Renormalization of one-pion exchange and power counting

    NARCIS (Netherlands)

    Nogga, A; Timmermans, RGE; van Kolck, U

    2005-01-01

    The renormalization of the chiral nuclear interactions is studied. In leading order, the cutoff dependence is related to the singular tensor interaction of the one-pion exchange potential. In S waves and in higher partial waves where the tensor force is repulsive this cutoff dependence can be

  5. Pion-nucleus scattering at around the DELTA (1232) resonance

    CERN Document Server

    Ahmed, H S; Rahman, M A; Rahman, S N

    2003-01-01

    The pion-nucleus scattering around 200 MeV and just above 1200 MeV is dominated by strong, broad DELTA (3,3) and weak resonances in the pi sup+-N interaction. The interaction to a first approximation can be described as diffraction process. Since it is well known that the strength of the pi sup + N and pi sup - N interactions are quite different from each other at the resonances, the analyses of differential cross section for pi sup + N and pi sup - N elastic scattering data in the region of low-lying pion-nucleus resonances will be a good test of different strengths. In the present work we analyze pions scattering from nuclei sup 9 Be, sup 2 sup 8 Si, sup 5 sup 8 Ni, sup 8 sup 9 Y and sup 2 sup 0 sup 8 Pb at incident pion energies between 50 and 291 MeV within the framework of the three parameter version of the Strong Absorption Model of Frahn and Venter. All the oscillations in the elastic scattering experimental data and for the experimental angular distribution leading to 2 sup + and 3 sup - collective st...

  6. Resonance production and decay in pion induced collisions with HADES

    Directory of Open Access Journals (Sweden)

    Scozzi Federico

    2017-01-01

    Full Text Available The main goal of the High Acceptance Di-Electron experiment (HADES at GSI is the study of hadronic matter in the 1-3.5 GeV/nucleon incident energy range. HADES results on e+ e− production in proton-nucleus reactions and in nucleus-nucleus collisions demonstrate a strong enhancement of the dilepton yield relative to a reference spectrum obtained from elementary nucleon-nucleon reactions. These observations point to a strong modification of the in-medium ρ spectral function driven by the coupling of the ρ to baryon-resonance hole states. However, to scrutinize this conjecture, a precise study of the role of the ρ meson in electromagnetic baryon-resonance transitions in the time-like region is mandatory. In order to perform this study, HADES has started a dedicated pion-nucleon programme. For the first time a combined measurement of hadronic and dielectron final states have been performed in π−-N reactions at four different pion beam momenta (0.656, 0.69, 0.748 and 0.8 GeV/c. First results on exclusive channels with one pion π−-p and two pions (nπ+π−, pπ−π0 in the final state, which are currently analysed within the partial wave analysis (PWA framework of the Bonn-Gatchina group, are discussed. Finally first results for the dielectron analysis will be shown.

  7. Pion linac as an energy-tagged ν source

    Directory of Open Access Journals (Sweden)

    T. Goldman

    2008-12-01

    Full Text Available The energy spectrum and flux of neutrinos from a linear pion accelerator are calculated analytically under the assumption of a uniform accelerating gradient. The energy of a neutrino from this source reacting in a detector can be determined from timing and event position information.

  8. Renormalization of NN Interaction with Relativistic Chiral Two Pion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Higa, R; Valderrama, M Pavon; Arriola, E Ruiz

    2007-06-14

    The renormalization of the NN interaction with the Chiral Two Pion Exchange Potential computed using relativistic baryon chiral perturbation theory is considered. The short distance singularity reduces the number of counter-terms to about a half as those in the heavy-baryon expansion. Phase shifts and deuteron properties are evaluated and a general overall agreement is observed.

  9. Bose-Einstein correlations of three charged pions in hadronic $Z^{0}$ decays

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bobinski, M; Bock, P; Böhme, J; Boutemeur, M; Braibant, S; Bright-Thomas, P G; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Ciocca, C; Clarke, P E L; Clay, E; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; de Roeck, A; Desch, Klaus; Dienes, B; Dixit, M S; Doucet, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Estabrooks, P G; Etzion, E; Evans, H G; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Höcker, Andreas; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jacob, F R; Jawahery, A; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jovanovic, P; Junk, T R; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; Liebisch, R; List, B; Littlewood, C; Lloyd, A W; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markopoulos, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Mir, R; Mohr, W; Montanari, A; Mori, T; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, James L; Plane, D E; Poffenberger, P R; Poli, B; Polok, J; Przybycien, M B; Rembser, C; Rick, Hartmut; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Roscoe, K; Rossi, A M; Rozen, Y; Runge, K; Runólfsson, O; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schieck, J; Schmitt, B; Schmitt, S; Schöning, A; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Sproston, M; Stahl, A; Stephens, K; Steuerer, J; Stoll, K; Strom, D; Ströhmer, R; Tafirout, R; Talbot, S D; Tanaka, S; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Van Kooten, R; Vannerem, P; Verzocchi, M; Vikas, P; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \\lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \\lambda_3 value by 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.

  10. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP, VOLUME 57, HIGH PT PHYSICS AT RHIC, DECEMBER 2-6, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Kretzer, Stefan; Venugopalan, Raju; Vogelsang, Werner

    2004-02-18

    The AuAu, dAu, and pp collision modes of the RHIC collider at BNL have led to the publication of exciting high p{perpendicular} particle production data. There have also been two physics runs with polarized protons, and preliminary results on the double-spin asymmetry for pion production had been presented very recently. The ontological questions behind these measurements are fascinating: Did RHIC collisions create a Quark-Gluon-Plasma phase and did they verify the Color Glass Condensate as the high energy limit of QCD? Will the Spin Crisis finally be resolved in terms of gluon polarization and what new surprises are we yet to meet for Transverse Spin? Phenomena related to sub-microscopic questions as important as these call for interpretations that are footed in solid theory. At large p{perpendicular}, perturbative concepts are legitimately expected to provide useful approaches. The corresponding hard parton dynamics are, in several ways, key to unraveling the initial or final state and collisional phase of hard scattering events in vacuum as well as in hot or cold nuclear matter. Before the advent of RHIC data, a RIKEN-BNL workshop had been held at BNL in March 1999 on ''Hard Parton Physics in High Energy Nuclear Collisions''. The 2003 workshop on ''High p{perpendicular} Physics at RHIC'' was a logical continuation of this previous workshop. It gave the opportunity to revisit the 1999 expectations in the light of what has been found in the meantime and, at the same time, to critically discuss the underlying theoretical concepts. We brought together theorists who have done seminal work on the foundations of parton phenomenology in field theory, with theorists and experimentalists who are presently working on RHIC phenomenology. The participants were both from a high-energy physics and nuclear physics background and it remains only to be said here that this chemistry worked perfectly and the workshop was a great success.

  11. Study of the Two-pion Photoproduction on the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Lewis P. [Univ. of South Carolina, Columbia, SC (United States)

    2012-12-01

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large

  12. Large-angle production of charged pions with incident pion beams on nuclear targets

    CERN Document Server

    Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, S.; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G.; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.

    2009-01-01

    Measurements of the double-differential pi+/- production cross-section in the range of momentum 100 MeV/c <= p <= 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad using pi+/- beams incident on beryllium, aluminium, carbon, copper, tin, tantalum and lead targets are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a solid target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d2sigma/dpdtheta at six incident beam momenta. Data at 3 GeV/c, 5 GeV/c, 8 GeV/c, and 12 GeV/c are available for all targets while additional data at 8.9 GeV/...

  13. Production of Mesons and Baryons at High Rapidity and High Pt in Proton-Proton Collisions at $\\sqrt{s}$ = 200 GeV

    CERN Document Server

    Arsene, I; Beavis, D; Bekele, S; Besliu, C; Budick, B; Bøggild, H; Chasman, C; Christensen, C H; Dalsgaard, H H; Debbe, R; Gaardhøje, J J; Hagel, K; Ito, H; Jipa, A; Johnson, E B; Jorgensen, C E; Karabowicz, R; Kim, E J; Larsen, T M; Lee, J H; Lindal, S; Løvhøiden, G; Majka, Z; Murray, M; Natowitz, J B; Nielsen, B S; Nygård, C; Planeta, R; Rami, F; Renault, F; Ristea, C; Ristea, O; Röhrich, D; Samset, B H; Sanders, S J; Scheetz, R A; Staszel, P; Tveter, T S; Videbaek, F; Wada, R; Yang, H; Yin, Z; Zgura, I S; al, et

    2007-01-01

    We present particle spectra for charged hadrons $\\pi^\\pm, K^\\pm, p$ and $\\bar{p}$ from pp collisions at $\\sqrt{s}$=200$ GeV measured for the first time at forward rapidities (2.95 and 3.3). The kinematics of these measurements are skewed in a way that probes the small momentum fraction in one of the protons and large fractions in the other. Large proton to pion ratios are observed at values of transverse momentum that extend up to 4 GeV/c, where protons have momenta up to 35 GeV. Next-to-leading order perturbative QCD calculations describe the production of pions and kaons well at these rapidities, but fail to account for the large proton yields and small $\\bar{p}/p$ ratios associated with baryon transport.

  14. Production spectra of zero-degree neutral particles measured by the LHCf experiment

    Directory of Open Access Journals (Sweden)

    Tiberio A.

    2017-01-01

    In this paper, latest published physics results from p-p and p-Pb collisions (at √s = 7, 2.76 TeV and sNN = 5.02 TeV, respectively compared with Monte Carlo predictions of DPMJET, EPOS, PYTHIA, QGSJET and SIBYLL event generators will be presented. In particular, the inclusive energy spectra of neutrons in p-p collisions and the transverse and longitudinal momentum spectra of neutral pions for different pseudo-rapidity ranges in p-p and p-Pb collisions will be shown; then, test of Feynman scaling hypothesis using neutral pion spectra will be discussed. Preliminary results of photon inclusive energy spectra in p-p collisions at √s = 13 TeV will be also presented.

  15. Evaluation on Geant4 Hadronic Models for Pion Minus, Pion Plus and Neutron Particles as Major Antiproton Annihilation Products.

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Mohammadi, Mohammad Mehdi; Reiazi, Reza; Jabbari, Keyvan

    2015-01-01

    Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 × 20 × 20 cm(3) water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in

  16. Pion Electroproduction form Helium 3, Deuterium, and Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Avery, Stephen Milton [Hampton Univ., Hampton, VA (United States)

    2002-05-01

    A series of measurements for pion electroproduction from helium-3, deuterium, and hydrogen were completed at the Thomas Jefferson National Accelerator Facility by the NucPi Collaboration. E91003 began taking data in February 1998 and was completed in April 1998. The longitudinal and transverse parts of the differential cross section were extracted, by means of a Rosenbluth type separation, in the direction parallel to the virtual photon, at Q 2 = 0.4 GeV 2 , for W = 1.15 and W = 1.6 GeV. The mass dependence of the longitudinal cross section should provide insight into the surprising apparent absence of any significant cross section enhancement due to excess pions in the nuclear medium.

  17. The pion and proton mass in finite volume

    Energy Technology Data Exchange (ETDEWEB)

    Colangelo, Gilberto [Institut fuer Theoretische Physik der Universitaet Bern, Sidlerstr. 5, 3012 Bern (Switzerland); Fuhrer, Andreas [Institut fuer Theoretische Physik der Universitaet Bern, Sidlerstr. 5, 3012 Bern (Switzerland); Haefeli, Christoph [Institut fuer Theoretische Physik der Universitaet Bern, Sidlerstr. 5, 3012 Bern (Switzerland)

    2006-03-15

    We calculate the finite volume effects for the pion and nucleon mass. For the pion mass we present the results of a full two-loop calculation in chiral perturbation theory. The outcome shows that the resummed version of the Luescher formula we presented in an earlier work does indeed give an excellent approximation to the two-loop result. In view of this result we apply the same resummed formula to the nucleon mass. In the nucleon sector the extension of the chiral expansion to higher quark masses appears to be more problematic and it is therefore more difficult to make reliable predictions for the size of the finite volume effects. We present some preliminary numerical estimates.

  18. "Soft-pion" production in the reaction NN-->NNπ

    Science.gov (United States)

    Dubach, J.; Silbar, R. R.; Kloet, W. M.

    1980-12-01

    We examine the reaction NN-->NNπ for "soft-pion" kinematics (p-->π=0 in the center of mass). An earlier calculation based on the Adler-Dothan theorem severely underestimated the p-->π=0 cross section for pp-->npπ+ at 740 MeV. We attempt to understand this discrepancy in the context of a relativistic, unitary, three-body isobar model. The postemission Δ-pole contributions are shown to be very important, even for these "soft-pion" kinematics. Relatively high partial waves in the NN-->NΔ isobar amplitude are significant. However, after summing all the postemission and preemission diagrams, the discrepancy with experiment is only partially removed.

  19. Quark mass functions and pion structure in Minkowski space

    Energy Technology Data Exchange (ETDEWEB)

    Biernat, Elmer P. [CFTP, Institute Superior Tecnico; Gross, Franz L. [JLAB; Pena, Maria Teresa [CFTP, Institute Superior Tecnico; Stadler, Alfred [University of Evora

    2014-03-01

    We present a study of the dressed quark mass function and the pion structure in Minkowski space using the Covariant Spectator Theory (CST). The quark propagators are dressed with the same kernel that describes the interaction between different quarks. We use an interaction kernel in momentum space that is a relativistic generalization of the linear confining q-qbar potential and a constant potential shift that defines the energy scale. The confining interaction has a Lorentz scalar part that is not chirally invariant by itself but decouples from the equations in the chiral limit and therefore allows the Nambu--Jona-Lasinio (NJL) mechanism to work. We adjust the parameters of our quark mass function calculated in Minkowski-space to agree with LQCD data obtained in Euclidean space. Results of a calculation of the pion electromagnetic form factor in the relativistic impulse approximation using the same mass function are presented and compared with experimental data.

  20. Polarization transfer in weak pion production off the nucleon

    Science.gov (United States)

    Graczyk, Krzysztof M.; Kowal, Beata E.

    2018-01-01

    Polarization transfer (PT) observables in the single pion production induced by the charged current interaction of the neutrino with the nucleon are examined. The polarization components of the final nucleon and the charged lepton are calculated within two models for the pion production. The predictions are made for neutrino energy of the order of 1 GeV as well as for the T2K energy distribution. It is demonstrated that the PT observables, the degree of polarization and the polarization components of outgoing fermions, are sensitive to assumptions about the nonresonant background model. In particular it is shown that the normal components of the polarization of the outgoing nucleon and the lepton are determined by the interference between the resonant (RES) and nonresonant (NB) amplitudes. Moreover, the sign of the normal component of the polarization of the charged lepton is fixed by the relative sign between the RES and the NB amplitudes.

  1. Measurement of the pion branching ratio at TRIUMF

    Science.gov (United States)

    Malbrunot, C.; Aguilar-Arevalo, A. A.; Aoki, M.; Blecher, M.; Britton, D. I.; Bryman, D. A.; Chen, S.; Comfort, J.; Ding, M.; Doria, L.; Gumplinger, P.; Hussein, A.; Igarashi, Y.; Ito, S.; Kettell, S. H.; Kuno, Y.; Kurchaninov, L.; Littenberg, L.; Numao, T.; Sher, A.; Sullivan, T.; Vavilov, D.; Yoshida, M.

    2012-09-01

    The branching ratio of pion decays, R = Γ(π+→e+νe+π+→e+νeγ)/Γ(π+→μ+νμ+π+→μ+νμγ is one of the most accurately calculated decay processes involving hadrons and has provided one of the most stringent tests of the hypothesis of electron-muon universality in weak interactions. The current experimental branching ratio Rexp = (1.230±0.004)×10-4 is 40 times less precise than the theoretical prediction RSM = 1.2352(1)10-4. The TRIUMF PIENU experiment aims at measuring the pion branching ratio with a precision improved by at least a factor five.

  2. Measurement of Neutrino Induced, Charged Current, Charged Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)

    2009-05-01

    Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.

  3. Photon annd pion production in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Blann, M.

    1989-05-01

    In this paper we describe different formulations for treating the nucleon-nucleon transport physics. These will all be semi-classical treatments; however considerable work has been done considering the relationship between quantal and semi-classical formulations. We discuss additional input specific to calculation of pion and photon yields, and present comparisons between calculated and experimental results, mostly for high energy photons. Conclusions and suggestions for future work are presented in the last section. 65 refs., 7 figs.

  4. Quark condensate effects on charmonium-pion scattering

    Indian Academy of Sciences (India)

    60, No. 5. — journal of. May 2003 physics pp. 1113–1116. Quark condensate effects on charmonium-pion scattering. F S NAVARRA and M NIELSEN. Instituto de Fısica, Universidade de S˜ao Paulo, C.P. 66318, 05389-970 S˜ao Paulo, Brazil. Abstract. The J ψπ. ¯DD£ ¯DD, ¯D£D£ and ¯D D£ cross-sections as a function of.

  5. Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    McKenney, Joshua R. [North Carolina State Univ., Raleigh, NC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Univ. of North Carolina, Chapel Hill, NC (United States); Sato Gonzalez, Nobuo; Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ji, Chueng-Ryong [North Carolina State Univ., Raleigh, NC (United States)

    2016-03-01

    We examine the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA and the $\\bar{d}-\\bar{u}$ flavor asymmetry in the proton. A detailed $\\chi^2$ analysis of the ZEUS and H1 cross sections, when combined with constraints on the pion flux from Drell-Yan data, allows regions of applicability of one-pion exchange to be delineated. The analysis disfavors several models of the pion flux used in the literature, and yields an improved extraction of the pion structure function and its uncertainties at parton momentum fractions in the pion of $4 \\times 10^{-4} \\lesssim x_\\pi \\lesssim 0.05$ at a scale of $Q^2$=10 GeV$^2$. Based on the fit results, we provide estimates for leading proton structure functions in upcoming tagged deep-inelastic scattering experiments at Jefferson Lab on the deuteron with forward protons.

  6. Two-pion correlations in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Zajc, W.A.

    1982-08-01

    An application of intensity interferometry to relativistic heavy ion collisions is reported. Specifically, the correlation between two like-charged pions is used to study the reactions Ar+KCl..-->..2..pi../sup +-/+X and Ne+NaF..-->..2..pi../sup -/+X. Source sizes are obtained that are consistent with a simple geometric interpretation. Lifetimes are less well determined but are indicative of a faster pion production process than predicted by Monte Carlo cascade calculations. There appears to be a substantial coherent component of the pion source, although measurement is complicated by the presence of final state interactions. Additionally, the generation of spectra of uncorrelated events is discussed. In particular, the influence of the correlation function on the background spectrum is analyzed, and a prescription for removal of this influence is given. A formulation to describe the statistical errors in the background is also presented. Finally, drawing from the available literature, a self-contained introduction to Bose-Einstein correlations and the Hanbury-Brown - Twiss effect is provided, with an emphasis on points of contact between classical and quantum mechanical descriptions.

  7. Pion transition form factor in k{sub T} factorization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hsiang-nan [Academica Sinica, Taipei, Taiwan (China). Inst. of Physics; Tsing-Hua Univ., Hsinchu, Taiwan (China). Dept. of Phyiscs; National Cheng-Kung Univ., Tainan, Taiwan (China). Dept. of Physics; National Cheng-Chi Univ, Taipei, Taiwan (China). Inst. of Applied Physics; Mishima, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-07-15

    It has been pointed out that the recent BaBar data on the {pi}{gamma}{sup *} {yields} {gamma} transition form factor F{sub {pi}}{sub {gamma}}(Q{sup 2}) at low (high) momentum transfer squared Q{sup 2} indicate an asymptotic (flat) pion distribution amplitude. These seemingly contradictory observations can be reconciled in the k{sub T} factorization theorem: the increase of the measured Q{sup 2}FF{sub {pi}}{sub {gamma}}(Q{sup 2}) for Q{sup 2} > 10 GeV{sup 2} is explained by convoluting a k{sub T} dependent hard kernel with a flat pion distribution amplitude, k{sub T} being a parton transverse momentum. The low Q{sup 2} data are accommodated by including the resummation of {alpha}{sub s} ln{sup 2}x, x being a parton momentum fraction, which provides a stronger suppression at the endpoints of x. The next-to-leading-order correction to the pion transition form factor is found to be less than 20% in the considered range of Q{sup 2}. (orig.)

  8. Electromagnetic Charge Radius of the Pion at High Precision

    Science.gov (United States)

    Ananthanarayan, B.; Caprini, Irinel; Das, Diganta

    2017-09-01

    We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.

  9. Coulomb effects on pions produced in heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.P.

    1981-11-01

    Double differential cross sections for the production of ..pi../sup +/ and ..pi../sup -/ near the velocity of the incident beam for pion lab angles less than 40 degrees are presented. The experimental apparatus and the techniques are discussed. Beams of /sup 20/Ne with E/A from 80 to 655 MeV and /sup 40/Ar with E/A = 535 MeV incident on Be, C, NaF, KC1, Cu, and U targets were used. A sharp peak in the ..pi../sup -/ spectrum and a depression in the ..pi../sup +/ spectrum were observed at zero degrees near the incident beam velocity. The effect is explained in terms of Coulomb interactions between the pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffman and an effective projectile fragment charge are made. The relationship between these data and previously measured pion production and projectile fragmentation data is discussed. The data are also compared to some theoretical models. A simple expression is given for the differential cross section as a function of the projectile mass, target mass, and beam energy.

  10. Inelastic pion scattering by /sup 13/C at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in /sup 13/C at an incident energy of 65 MeV. The data include results from both ..pi../sup +/ and ..pi../sup -/ measurements. In addition, ..pi../sup -/ measurements were made at T/sub ..pi../ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2/sup +/ state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs.

  11. Soliton-like states of the pion field in nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Kurilkin, N.N.; Mishustin, I.N.; Khodel' , V.A.

    1982-07-01

    The Weinberg nonlinear Lagrangian is used to demonstrate the possibility that soliton-like clusters of the pion field exist in nuclear matter. These clusters are multipion coherent states which interact strongly with the surrounding nuclear matter. The stability of these states with respect to various decay channels, in particular, decay into separate pions, is studied. The properties of these pionic solitons and their relation to the parameters of the spectrum of linear pion excitations in nuclear matter are discussed.

  12. Pion-exchange contribution to the parity-violating asymmetry in pp scattering

    Science.gov (United States)

    Silbar, Richard R.; Kloet, W. M.; Kisslinger, Leonard S.; Dubach, J.

    1989-05-01

    Charged pion exchange, producing nΔ++ intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  13. Pion-exchange contribution to the parity-violating asymmetry in pp scattering

    Energy Technology Data Exchange (ETDEWEB)

    Silbar, R.R. (Los Alamos National Laboratory, Los Alamos, NM 87545 (US)); Kloet, W.M. (Rutgers University, New Brunswick, NJ 08903); Kisslinger, L.S. (Carnegie-Mellon University, Pittsburgh, PA 15213); Dubach, J. (University of Massachusetts, Amherst, MA 01003)

    1989-05-01

    Charged pion exchange, producing n{Delta}{sup ++} intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  14. FINITE PARTICLE NUMBER EFFECTS IN HIGH-ENERGY NUCLEAR COLLISIONS: IMPLICATIONS ON PION SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Bohrmann, Steffen; Knoll, Jorn

    1980-05-01

    We study pion production from high energy nuclear collisions by means of a simple statistical model. The shapes of the observed spectra exclude that all pions result from freely decaying delta resonances. Rather, they have to participate in kinetic equilibration processes. Finite particle number effects are found to be very important: equilibration does not occur globally but rather in groups of only a few particles. The pion production rates cannot be explained in terms of a chemical equilibrium.

  15. Analysis Of Neutral-d Decays To A Charged Kaon, A Charged Pion, And A Neutral Pion: Search For Neutral-d Mixing, And Measurements Of The Doubly Cabibbo-suppressed Decay Rate And Resonance Contributions

    CERN Document Server

    Wilson, M G

    2005-01-01

    Analyzing D0 → K +π- π0 decays, herein are presented the methods and results of a search for D0- D¯0 mixing, a measurement of the branching ratio R ≡ Γ(D0 → K+π- π0)/Γ( D0 → K-π +π0), and measurements of the contributions from D0 → K+π -, K*+π-, K*0π0; 230.4fb-1 of data collected from the BABAR detector at the PEP-II collider during 2000-2004 (Runs 1-4) are analyzed. An event-level tagging technique is developed, which facilitates the accurate determination of doubly Cabibbo-suppressed resonance contributions by suppressing background from Cabibbo-favored decays. The branching ratio is measured as R = (0.214 ± 0.008 (stat)±0.008 (syst))%, with (46.1±3.3 (stat)±2.9 (syst))% of D0 → K+π -π0 decays proceeding through the channel D0 → K*+π -. The data are consistent with the null-D- mixing h...

  16. Evaluation on Geant4 Hadronic Models for Pion Minus, Pion Plus and Neutron Particles as Major Antiproton Annihilation Products

    OpenAIRE

    Tavakoli, Mohammad Bagher; Mohammadi, Mohammad Mehdi; Reiazi, Reza; Jabbari, Keyvan

    2015-01-01

    Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the f...

  17. Neutral Buoyancy Laboratory (NBL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility,...

  18. Pion absorption in nuclei: The (. pi. /sup + -/,p) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, C.S.

    1987-05-01

    Reported here is the first experiment to measure the excitation of discrete final states following the (..pi../sup -/,p) reaction. The Energetic Pion Channel and Spectrometer (EPICS) at the Los Alamos National Laboratory and the High Resolution Pion Channel and Spectrometer (..pi..M1-SUSI) at the Swiss Institute for Nuclear Physics were used for this high resolution study of (..pi../sup + -/,p) reactions. An average energy resolution of 500 KeV and 700 KeV was achieved at EPICS and ..pi..M1-SUSI respectively. At EPICS these reactions were measured at T/sub ..pi../ = 120 MeV and theta/sub lab/ = 25/sup 0/ on /sup 24/Mg, /sup 27/Al, /sup 40/Ca and /sup 58/Ni; /sup 12/C(..pi../sup -/,p) was measured at T/sub ..pi../ = 145 MeV. At ..pi..M1-SUSI these reactions were measured at T/sub ..pi../ = 90 MeV and at theta/sub lab/ = 20/sup 0/ on /sup 23/Na and /sup 24/Mg. The measurement includes both the differential cross sections and continuum up to an excitation energy of 40 MeV. In /sup 23/Na, /sup 24/Mg, and /sup 27/Al there are peaks in the low excitation region. The shape of the continuum in an excitation energy range of 10 to 40 MeV was found to be independent of pion charge and target mass. The magnitude of proton yield from all the targets at T/sub ..pi../ = 120 MeV is more than twenty four times larger for ..pi../sup +/ than for ..pi../sup -/. Also, the cross sections for both reactions on /sup 24/Mg is slightly enhanced compared to other nuclei. At T/sub ..pi../ = 90 MeV the ratio of the proton yield for ..pi../sup +/ to ..pi../sup -/ absorption drops down to fourteen. This high ratio and its energy dependence supports the idea of a two nucleon pion absorption model. Pion absorption in the context of both the reaction mechanism and nuclear structure is discussed. 99 refs., 64 figs., 11 tabs.

  19. Pion-exchange contribution to the parity-violating asymmetry in p-->p scattering

    Science.gov (United States)

    Silbar, Richard R.; Kloet, W. M.; Kisslinger, Leonard S.; Dubach, J.

    1989-11-01

    Charged pion exchange, resulting in an nΔ++ state, contributes positively to the weak scattering asymmetry in longitudinally polarized p-->p scattering at medium energy. This pion-exchange contribution combined with the traditional ρ and ω ``elastic'' contributions moves the total theoretical prediction into better agreement with the 800-MeV experimental data point. The pion-exchange contribution has both inelastic and elastic scattering components and is sizable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  20. Pion-exchange contribution to the parity-violating asymmetry in rvec p p scattering

    Energy Technology Data Exchange (ETDEWEB)

    Silbar, R.R. (Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545 (US)); Kloet, W.M. (Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903); Kisslinger, L.S. (Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213); Dubach, J. (Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 Continuous Electron Beam Accelerator Facility (CEBAF), 12000 Jefferson Avenue, Newport News, Virginia 23606)

    1989-11-01

    Charged pion exchange, resulting in an {ital n}{Delta}{sup ++} state, contributes positively to the weak scattering asymmetry in longitudinally polarized {ital {rvec p}p} scattering at medium energy. This pion-exchange contribution combined with the traditional {rho} and {omega} elastic'' contributions moves the total theoretical prediction into better agreement with the 800-MeV experimental data point. The pion-exchange contribution has both inelastic and elastic scattering components and is sizable even below the pion production threshold. Strong distortions enhance the magnitude of the effect.

  1. Towards a model of pion generalized parton distributions from Dyson-Schwinger equations

    Energy Technology Data Exchange (ETDEWEB)

    Moutarde, H. [CEA, Centre de Saclay, IRFU/Service de Physique Nucléaire, F-91191 Gif-sur-Yvette (France)

    2015-04-10

    We compute the pion quark Generalized Parton Distribution H{sup q} and Double Distributions F{sup q} and G{sup q} in a coupled Bethe-Salpeter and Dyson-Schwinger approach. We use simple algebraic expressions inspired by the numerical resolution of Dyson-Schwinger and Bethe-Salpeter equations. We explicitly check the support and polynomiality properties, and the behavior under charge conjugation or time invariance of our model. We derive analytic expressions for the pion Double Distributions and Generalized Parton Distribution at vanishing pion momentum transfer at a low scale. Our model compares very well to experimental pion form factor or parton distribution function data.

  2. Decay constants of the pion and its excitations on the lattice.

    Energy Technology Data Exchange (ETDEWEB)

    Mastropas, Ekaterina V. [William and Mary College, JLAB; Richards, David G. [JLAB

    2014-07-01

    We present a calculation using lattice QCD of the ratios of decay constants of the excited states of the pion, to that of the pion ground state, at three values of the pion mass between 400 and 700 MeV, using an anisotropic clover fermion action with three flavors of quarks. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass. The strong suppression of the decay constant of the second excited state is consistent with its interpretation as a predominantly hybrid state.

  3. Search for coherent charged pion production in neutrino-carbon interactions.

    Science.gov (United States)

    Hasegawa, M; Aliu, E; Andringa, S; Aoki, S; Argyriades, J; Asakura, K; Ashie, R; Berns, H; Bhang, H; Blondel, A; Borghi, S; Bouchez, J; Burguet-Castell, J; Casper, D; Cavata, C; Cervera, A; Chen, S M; Cho, K O; Choi, J H; Dore, U; Espinal, X; Fechner, M; Fernandez, E; Fukuda, Y; Gomez-Cadenas, J; Gran, R; Hara, T; Hasegawa, T; Hayashi, K; Hayato, Y; Helmer, R L; Hill, J; Hiraide, K; Hosaka, J; Ichikawa, A K; Iinuma, M; Ikeda, A; Inagaki, T; Ishida, T; Ishihara, K; Ishii, T; Ishitsuka, M; Itow, Y; Iwashita, T; Jang, H I; Jeon, E J; Jeong, I S; Joo, K K; Jover, G; Jung, C K; Kajita, T; Kameda, J; Kaneyuki, K; Kato, I; Kearns, E; Kerr, D; Kim, C O; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kim, J Y; Kim, S B; Kitching, P; Kobayashi, K; Kobayashi, T; Konaka, A; Koshio, Y; Kropp, W; Kubota, J; Kudenko, Yu; Kuno, Y; Kutter, T; Learned, J; Likhoded, S; Lim, I T; Loverre, P F; Ludovici, L; Maesaka, H; Mallet, J; Mariani, C; Maruyama, T; Matsuno, S; Matveev, V; Mauger, C; McConnel, K; McGrew, C; Mikheyev, S; Minamino, A; Mine, S; Mineev, O; Mitsuda, C; Miura, M; Moriguchi, Y; Morita, T; Moriyama, S; Nakadaira, T; Nakahata, M; Nakamura, K; Nakano, I; Nakaya, T; Nakayama, S; Namba, T; Nambu, R; Nawang, S; Nishikawa, K; Nitta, K; Nova, F; Novella, P; Obayashi, Y; Okada, A; Okumura, K; Oser, S M; Oyama, Y; Pac, M Y; Pierre, F; Rodriguez, A; Saji, C; Sakuda, M; Sanchez, F; Sarrat, A; Sasaki, T; Sato, H; Scholberg, K; Schroeter, R; Sekiguchi, M; Sharkey, E; Shiozawa, M; Shiraishi, K; Sitjes, G; Smy, M; Sobel, H; Stone, J; Sulak, L; Suzuki, A; Suzuki, Y; Takahashi, T; Takenaga, Y; Takeuchi, Y; Taki, K; Takubo, Y; Tamura, N; Tanaka, M; Terri, R; T'jampens, S; Tornero-Lopez, A; Totsuka, Y; Ueda, S; Vagins, M; Whitehead, L; Walter, C W; Wang, W; Wilkes, R J; Yamada, S; Yamamoto, S; Yanagisawa, C; Yershov, N; Yokoyama, H; Yokoyama, M; Yoo, J; Yoshida, M; Zalipska, J

    2005-12-16

    We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.

  4. A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen

    CERN Document Server

    Ericson, Torleif Eric Oskar; Wycech, S

    2005-01-01

    A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).

  5. πN TDAs from charmonium production in association with a forward pion at P̅ANDA

    National Research Council Canada - National Science Library

    Ma B; Pire B; Semenov-Tian-Shansky K; Szymanowski L

    2014-01-01

    Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs) at P̅ANDA...

  6. Dynamic pion irradiation of unresectable soft tissue sarcomas

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, R.H.; Blattmann, H.J.; Thum, P.; Coray, A.; Crawford, J.F.; Kann, R.H.; Munkel, G.; Pedroni, E.; von Essen, C.F.; Zimmermann, A. (Paul Scherrer Institute, Villigen-PSI (Switzerland))

    1989-11-01

    Since November 1981, when pion irradiation was introduced for deep seated tumors at the Swiss Institute for Nuclear Research (SIN, now Paul Scherrer Institute, PSI) a dynamic, 3-dimensional spot scan treatment technique has been in use. To exploit this technique a special optimization treatment planning system has been designed. Of a total of 331 patients treated with pions from November 1981-December 1987, 35 were irradiated for unresectable soft tissue sarcomas. In 32/35 patients, tumor sites were retroperitoneal, pelvic or in the groin or thigh. Twenty-nine tumors had a maximum diameter of greater than 10 cm, 18 tumors of greater than 15 cm; 30 tumors had grade 2/3 and 32 Stage III B/IV A/IV B. Eight of 35 patients received a low pion total dose, 7-27 Gy. Twenty-seven patients received a total dose of 30-36 Gy, fraction size 150-170 cGy (90%-isodose), 20 fractions, 4 times per week. Of these 27 patients, severe late reactions appeared in five: 2/8 patients with extremity/groin sarcomas (1/2 caused by biopsy) and 3/19 patients with retroperitoneal/pelvic sarcomas (one a skin reaction after Actinomycin-D, one a small bowel reaction after 36 Gy, a dose no longer used). Seven of 27 patients had metastases at the beginning of irradiation. Three of 27 were treated with excisional biopsy, 9 with incisional biopsy or partial resection and in 15 patients biopsies were performed for histology only. The median follow-up of these 27 patients was 17 months (5-66). There was no progression in eight extremity/groin tumors but in 4 of 19 retroperitoneal/pelvic tumors. Three of these were marginal progressions. The actuarial 5-year rate of local tumor control is 64%; the actuarial 5-year survival rate of patients without metastases at the beginning of treatment is 58%.

  7. Pion Double Charge Exchange at 50 MeV on 14C

    Science.gov (United States)

    Navon, I.; Leitch, M. J.; Bryman, D. A.; Numao, T.; Schlatter, P.; Azuelos, G.; Poutissou, R.; Burnham, R. A.; Hasinoff, M.; Poutissou, J. M.; MacDonald, J. A.; Spuller, J. E.; Hargrove, C. K.; Mes, H.; Blecher, M.; Gotow, K.; Moinester, M.; Baer, H.

    1984-01-01

    The first measurement of pion double charge exchange at low energy is reported. The reaction 14C(π+,π-)14O was measured at an incident pion energy of 50 MeV. Differential cross sections of the double analog transition are given in the angular range 50°-120°. Strong nonanalog transitions were also observed.

  8. Diffraction model analysis of pion-12C elastic scattering at 800 MeV ...

    Indian Academy of Sciences (India)

    Elastic scattering of 800 MeV/c pions by 12C has been studied in the diffraction model with a view to determine pion optical potential by the method of inversion. Finding an earlier diffraction model analysis to be deficient in some respects, we propose a Glauber model based parametrization for the elastic -matrix and show ...

  9. Two-Pion Production in Proton--Proton Collisions Near Threshold at CELSIUS

    Science.gov (United States)

    Bilger, R.; Brodowski, W.; Calen, H.; Clement, H.; Dyring, J.; Ekstroem, C.; Fransson, K.; Greiff, J.; Gustafsson, L.; Haeggstroem, S.; Hoeistad, B.; Johanson, J.; Johansson, A.; Johansson, T.; Khoukaz, A.; Kilian, K.; Koch, I.; Kullander, S.; Kupsc, A.; Marciniewski, P.; Morosov, B.; Moertsell, A.; Oelert, W.; Ruber, R.; Schubert, U.; Shwartz, B.; Stepaniak, J.; Sukhanov, A.; Sundberg, P.; Turowiecki, A.; Wagner, G.; Wilhelmi, Z.; Zabierowski, J.; Zernov, A.; Zlomanczuk, J.

    1998-11-01

    Two-pion production reactions in proton-proton collisions near threshold are measured using an internal cluster-jet hydrogen target and the WASA/PROMICE detector at the CELSIUS storage ring. Four out of the five possible two-pion production reactions are measured simultaneously.

  10. Two-pion interferometry at small relative momentum in ultrarelativistic heavy ion collisions

    CERN Document Server

    Chen Xiao Fan; Chen Zhi Lai; Han Ling; Wang Qi

    2002-01-01

    The relations between the pion source parameters in two models in ultrarelativistic heavy ion collisions are given using pion interferometry at small relative momentum. And comparisons are made with the experimental results of 200A GeV O + Au collisions

  11. Dependence of the Interferometric Sizes of Pion Generation Volume on Sizes of Their Wave Packet

    CERN Document Server

    Anikina, M K; Lukstins, Yu P

    2002-01-01

    The influence of the pion initial wave packet sizes on sizes of the elements of the pion generation volume obtained by the interference method is investigated experimentally in the central MgMg interactions at 4.3 GeV/c per nucleon.

  12. Doubly-polarised pion photoproduction on the nucleon at MAMI

    Directory of Open Access Journals (Sweden)

    Costanza Susanna

    2017-01-01

    These new, high-quality doubly-polarised pion-photoproduction data sets provide a valuable input to the study of the nucleon structure and excitation spectrum by significantly constraining the electromagnetic multipole evaluation performed by the different available partial wave analysis models. Furthermore, the helicity dependent observables provide the main ingredient for the verification of the well-known Gerasimov-Drell-Hearn (GDH sum rule, which relates the helicity-dependent photoasborption process to the main static nucleon properties (mass, charge, spin.

  13. Pion transition form factor through Dyson-Schwinger equations

    Science.gov (United States)

    Raya, Khépani

    2016-10-01

    In the framework of Dyson-Schwinger equations (DSE), we compute the γ*γ→π0 transition form factor, G(Q2). For the first time, in a continuum approach to quantun chromodynamics (QCD), it was possible to compute G(Q2) on the whole domain of space-like momenta. Our result agrees with CELLO, CLEO and Belle collaborations and, with the well- known asymptotic QCD limit, 2ƒπ. Our analysis unifies this prediction with that of the pion's valence-quark parton distribution amplitude (PDA) and elastic electromagnetic form factor.

  14. Electroproduction of Photons and of Pawns on the Proton in Quadrimoment of Transfer Q2=1.0GeV2. Measure Cross Sections and Extraction of Polarizabilities Generalities; Electroproduction de Photons et de Pions sur le Proton au Quadrimoment de Transfert Q2=1.0GeV2. Mesure des Sections Efficaces et Extraction des Polarisabilites Generalisees

    Energy Technology Data Exchange (ETDEWEB)

    Laveissiere, Geraud [Blaise Pascal Univ., Aubiere (France)

    2001-11-06

    In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focused on the VCS experiment performed at Jefferson Lab in 1998.

  15. Energy dependence of negatively charged pion production in proton-proton interactions at the CERN SPS

    CERN Document Server

    AUTHOR|(SzGeCERN)663936; Dominik, Wojciech; Gaździck, Marek

    2016-01-01

    This thesis presents inclusive spectra of the negatively charged pions produced in inelastic proton-proton interactions measured at five beam momenta: 20, 31, 40, 80 and 158 GeV/c. The measurements were conducted in the NA61/SHINE experiment at CERN using a system of five Time Projection Chambers. The negatively charged pion spectra were calculated based on the negatively charged hadron spectra. Contribution of hadrons other than the primary pions was removed using EPOS simulations. The results were corrected for effects related to detection, acceptance, reconstruction efficiency and the analysis technique. Two-dimensional spectra were derived as a function of rapidity and transverse momentum or transverse mass. The spectra were parametrised by widths of the rapidity distributions, inverse slope parameters of the transverse mass distributions, mean transverse masses and the total pion multiplicities. The negatively charged pion spectra in proton-proton interactions belong to a broad NA61/SHINE programme of se...

  16. Chiral behaviour of the pion decay constant in N{sub f}=2 QCD

    Energy Technology Data Exchange (ETDEWEB)

    Lottini, Stefano [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Collaboration: ALPHA Collaboration

    2013-11-15

    As increased statistics and new ensembles with light pions have become available within the CLS effort, we complete previous work by inspecting the chiral behaviour of the pion decay constant. We discuss the validity of Chiral Perturbation Theory ({chi}PT) and examine the results concerning the pion decay constant and the ensuing scale setting, the pion mass squared in units of the quark mass, and the ratio of decay constants f{sub K}=f{sub {pi}}; along the way, the relevant low-energy constants of SU(2) {chi}PT are estimated. All simulations were performed with two dynamical flavours of nonperturbatively O(a)-improved Wilson fermions, on volumes with m{sub {pi}}L{>=}4, pion masses{>=}192 MeV and lattice spacings down to 0.048 fm. Our error analysis takes into account the effect of slow modes on the autocorrelations.

  17. Pion form factor at spacelike momentum transfers from local-duality QCD sum rule

    Energy Technology Data Exchange (ETDEWEB)

    Braguta, Victor [Institute for High Energy Physics, 142284 Protvino (Russian Federation); Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Nuclear Physics Institute, Moscow State University, 119991 Moscow (Russian Federation)], E-mail: dmitri_melikhov@gmx.de

    2008-04-03

    We study the pion form factor in a broad range of spacelike momentum transfers within the local-duality version of QCD sum rules. We make use of the recently calculated two-loop double spectral density of the correlator including O(1) and O({alpha}{sub s}) terms, which allows us to give predictions for the pion form factor and to study the interplay between the nonperturbative and perturbative contributions to the pion form factor without any reference to the pion distribution amplitude. Our results demonstrate the dominance of the nonperturbative contribution to the form factor up to relatively large values of the momentum transfer: namely, the nonperturbative O(1) term, which provides the 1/Q{sup 4} power correction, gives more than half of the pion form factor in the region Q{sup 2}{<=}20 GeV{sup 2}.

  18. The longitudinal and transverse distributions of the pion wave function from the present experimental data on the pion-photon transition form factor

    Science.gov (United States)

    Zhong, Tao; Wu, Xing-Gang; Huang, Tao

    2016-07-01

    The low-energy and high-energy behavior of the pion-photon transition form factor F_{π γ }(Q^2) are sensitive to the transverse and longitudinal distributions of the pion wave function, respectively. A careful study of F_{π γ }(Q^2) shall thus provide helpful constraints on the properties of the pion wave function. In this paper, we present a combined analysis of the data on F_{π γ }(Q^2) reported by the CELLO, the CLEO, the BABAR, and the BELLE Collaborations. It is performed by using the method of least squares. By using the combined measurements of the BELLE and CLEO Collaborations, the pion wave function longitudinal and transverse behavior can be fixed to a certain degree, i.e. we obtain β in [0.691,0.757] GeV and B in [0.00,0.235] for P_{χ ^2} ≥ 90 %, where β and B are two parameters of a convenient pion wave function model. It is noted that the distribution amplitude of such a pion wave function can mimic various longitudinal behaviors, as suggested in the literature under a proper choice of parameters. We observe that the CELLO, CLEO, and BELLE data are consistent with each other, all of which prefer the asymptotic-like distribution amplitude; while the BABAR data prefers a more broad distribution amplitude, such as the CZ-like one.

  19. Pion-photon transition: The new QCD frontier

    Science.gov (United States)

    Bakulev, A. P.; Mikhailov, S. V.; Pimikov, A. V.; Stefanis, N. G.

    2011-08-01

    We perform a detailed analysis of all existing data (CELLO, CLEO, BABAR) on the pion-photon transition form factor by means of light-cone sum rules in which we include the next-to-leading order QCD radiative corrections and the twist-four contributions. The next-to-next-to-leading order radiative correction together with the twist-six contribution are also taken into account in terms of theoretical uncertainties. Keeping only the first two Gegenbauer coefficients a2 and a4, we show that the 1σ error ellipse of all data up to 9GeV2 greatly overlaps with the set of pion distribution amplitudes obtained from nonlocal QCD sum rules—within the range of uncertainties due to twist-four. This remains valid also for the projection of the 1σ error ellipsoid on the (a2,a4) plane when including a6. We argue that it is not possible to accommodate the high-Q2 tail of the BABAR data with the same accuracy, despite opposite claims by other authors, and conclude that the BABAR data still pose a challenge to QCD.

  20. The Pion Form Factor Within the Hidden Local Symmetry Model

    CERN Document Server

    Benayoun, Maurice; DelBuono, L.; Leruste, P.; O'Connell, Heath Bland; Leruste, Ph.

    2003-01-01

    We analyze a pion form factor formulation which fulfills the Analyticity requirement within the Hidden Local Symmetry (HLS) Model. We show that it implies an $s$--dependent dressing of the $\\rho-\\gamma$ VMD coupling and an account of several coupled channels. The corresponding function $F_\\pi(s)$ provides nice fits of the pion form factor data from $s=-0.25$ to $s=1$ GeV$^2$. It is shown that the coupling to $K \\bar{K}$ has little effects, while $\\omg \\pi^0$ improves significantly the fit quality below the $\\phi$ mass. All parameters, except for the subtraction polynomial coefficients are fixed from the rest of the HLS phenomenology. The fits show consistency with the expected behaviour of $F_\\pi(s)$ at $s=0$ up to ${\\cal O} (s^2)$ and with the phase shift data on $\\delta_1^1(s)$ from threshold to somewhat above the $\\phi$ mass. The $\\omg$ sector is also examined in relation with recent data from CMD--2.

  1. Search for dinucleon decay into pions at Super-Kamiokande

    CERN Document Server

    Gustafson, J; Haga, Y; Hayato, Y; Ikeda, M; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakajima, T; Nakano, Y; Nakayama, S; Orii, A; Sekiya, H; Shiozawa, M; Takeda, A; Tanaka, H; Tomura, T; Wendell, R A; Irvine, T; Kajita, T; Kametani, I; Kaneyuki, K; Nishimura, Y; Richard, E; Okumura, K; Labarga, L; Fernandez, P; Berkman, S; Tanaka, H A; Tobayama, S; Kearns, E; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Carminati, G; Kropp, W R; Mine, S; Weatherly, P; Renshaw, A; Smy, M B; Sobel, H W; Takhistov, V; Ganezer, K S; Hartfiel, B L; Hill, J; Hong, N; Kim, J Y; Lim, I T; Akiri, T; Himmel, A; Scholberg, K; Walter, C W; Wongjirad, T; Ishizuka, T; Tasaka, S; Jang, J S; Learned, J G; Matsuno, S; Smith, S N; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Suzuki, T TsukamotoA T; Takeuchi, Y; Yano, T; Hirota, S; Huang, K; Ieki, K; Kikawa, T; Minamino, A; Nakaya, T; Suzuki, K; Takahashi, S; Fukuda, Y; Choi, K; Itow, Y; Mitsuka, G; Suzuki, T; Mijakowski, P; Hignight, J; Imber, J; Jung, C K; Palomino, J L; Yanagisawa, C; Ishino, H; Kayano, T; Kibayashi, A; Koshio, Y; Mori, T; Sakuda, M; Kuno, Y; Tacik, R; Kim, S B; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Suda, Y; Totsuka, Y; Yokoyama, M; Bronner, C; Martens, K; Marti, Ll; Suzuki, Y; Vagins, M R; Martin, J F; de Perio, P; Konaka, A; Wilking, M J; Chen, S; Zhang, Y; Wilkes, R J

    2015-01-01

    A search for dinucleon decay into pions with the Super-Kamiokande detector has been performed with an exposure of 282.1 kiloton-years. Dinucleon decay is a process that violates baryon number by two units. We present the first search for dinucleon decay to pions in a large water Cherenkov detector. The modes $^{16}$O$(pp) \\rightarrow$ $^{14}$C$\\pi^{+}\\pi^{+}$, $^{16}$O$(pn) \\rightarrow$ $^{14}$N$\\pi^{+}\\pi^{0}$, and $^{16}$O$(nn) \\rightarrow$ $^{14}$O$\\pi^{0}\\pi^{0}$ are investigated. No significant excess in the Super-Kamiokande data has been found, so a lower limit on the lifetime of the process per oxygen nucleus is determined. These limits are: $\\tau_{pp\\rightarrow\\pi^{+}\\pi^{+}} > 7.22 \\times 10^{31}$ years, $\\tau_{pn\\rightarrow\\pi^{+}\\pi^{0}} > 1.70 \\times 10^{32}$ years, and $\\tau_{nn\\rightarrow\\pi^{0}\\pi^{0}} > 4.04 \\times 10^{32}$ years. The lower limits on each mode are about two orders of magnitude better than previous limits from searches for dinucleon decay in iron.

  2. Influence of pions on the hadron-quark phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, O.; Dutra, M.; Frederico, T.; Malheiro, M. [Departamento de Fisica, Instituto Tecnologico de Aeronautica-CTA, 12228-900, Sao Jose dos Campos (Brazil); Delfino, A. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, 24210-150, Boa Viagem, Niteroi RJ (Brazil)

    2013-05-06

    In this work we present the features of the hadron-quark phase transition diagrams in which the pions are included in the system. To construct such diagrams we use two different models in the description of the hadronic and quark sectors. At the quark level, we consider two distinct parametrizations of the Polyakov-Nambu-Jona-Lasinio (PNJL) models. In the hadronic side, we use a well known relativistic mean-field (RMF) nonlinear Walecka model. We show that the effect of the pions on the hadron-quark phase diagrams is to move the critical end point (CEP) of the transitions lines. Such an effect also depends on the value of the critical temperature (T{sub 0}) in the pure gauge sector used to parametrize the PNJL models. Here we treat the phase transitions using two values for T{sub 0}, namely, T{sub 0}= 270 MeV and T{sub 0}= 190 MeV. The last value is used to reproduce lattice QCD data for the transition temperature at zero chemical potential.

  3. Gargamelle: first neutral current

    CERN Multimedia

    1973-01-01

    This event shows the real tracks produced in the 1200 litre Gargamelle bubble chamber that provided the first confirmation of a neutral current interaction. A neutrino interacts with an electron, the track of which is seen horizontally, and emerges as a neutrino without producing a muon. The discovery of the neutral current was announced in the CERN main auditorium in July 1973.

  4. Subthreshold pion production in the reaction /sup 139/La + /sup 139/La. -->. pi. /sup + -/ + X

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.

    1988-01-01

    We have measured charged pion production in the reaction /sup 139/La + /sup 139/La ..-->.. ..pi../sup + -/ + X at three beam energies (246, 183 and 138 MeVnucleon) below the nucleon-nucleon threshold. Associated multiplicity for charged participants was obtained using a 110-element scintillator multiplicity array. Data were taken over the angular range of 21/degree/ to 67/degree/ in the laboratory (equivalent to 30/degree/ to 90/degree/ in the center of mass). Dependence of the spectra upon pion charge, energy and angle, beam energy, system mass and associated multiplicity was investigated. Based on the isotropic angular distibutions and the associated multiplicities for pion production, it appears that subthreshold pions in the range of our experiment are produced predominantly from a source at rest in the center of mass and involving a large number of nucleons. The general character of the subthreshold pion spectra is comparable to previous results above threshold. However, the scaling of the subthreshold pion yield with system mass deviates from the dependence observed in light systems, to an extent which cannot be explained by a simple nucleon-nucleon model. We also found charge dependent structure in the pion spectra, which we analysed in the framework of both Coulomb distortion and clustering models. We conclude that while we did not find clear evidence of collective effects in subthreshold pion production, it would be very worthwhile to conduct a systematic investigation of pion production for all charge states and over a range of angles, system masses and beam energies, below threshold. 170 refs., 78 figs., 10 tabs.

  5. Pion-photon transition form factor in light-cone sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Pimikov, A. V.; Bakulev, A. P.; Mikhailov, S. V.; Stefanis, N. G. [Departamento de Fisica Teorica -IFIC, Universidad de Valencia-CSIC, E-46100 Burjassot, Valencia (Spain) and Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2012-10-23

    We extract constraints on the pion distribution amplitude from available data on the pionphoton transition form factor in the framework of light-cone sum rules. A pronounced discrepancy (2.7 - 3){sigma} between the Gegenbauer expansion coefficients extracted from the CELLO, CLEO, and Belle experimental data relative to those from BaBar is found. Predictions for the pion-photon transition form factor are presented by employing a pion distribution amplitude obtained long ago from QCD sum rules with nonlocal condensates. These predictions comply with the Belle data but disagree with those of BaBar beyond 9 GeV{sup 2}.

  6. Nucleon structure from Lattice QCD using a nearly physical pion mass

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.R. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany); Engelhardt, M. [Department of Physics, New Mexico State University, Las Cruces, NM 88003 (United States); Krieg, S. [Bergische Universität Wuppertal, D-42119 Wuppertal (Germany); IAS, Jülich Supercomputing Centre, Forschungszentrum Jülich, D-52425 Jülich (Germany); Negele, J.W.; Pochinsky, A.V. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Syritsyn, S.N., E-mail: ssyritsyn@quark.phy.bnl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-06-27

    We report the first Lattice QCD calculation using the almost physical pion mass m{sub π}=149 MeV that agrees with experiment for four fundamental isovector observables characterizing the gross structure of the nucleon: the Dirac and Pauli radii, the magnetic moment, and the quark momentum fraction. The key to this success is the combination of using a nearly physical pion mass and excluding the contributions of excited states. An analogous calculation of the nucleon axial charge governing beta decay has inconsistencies indicating a source of bias at low pion masses not present for the other observables and yields a result that disagrees with experiment.

  7. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    OpenAIRE

    Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.

    2008-01-01

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of theta_cm ~ 150-170^o at several pion beam energies in the invariant mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P...

  8. Relativistic treatment of pion wave functions in the annihilation p¯ p→ π- π+

    Science.gov (United States)

    El-Bennich, B.; Kloet, W. M.

    2004-09-01

    Quark model intrinsic wave functions of highly energetic pions in the reaction p¯ p→ π- π+ are subjected to a relativistic treatment. The annihilation is described in a constituent quark model with A2 and R2 flavor-flux topology, and the annihilated quark-antiquark pairs are in 3P0 and 3S1 states. We study the effects of pure Lorentz transformations on the antiquark and quark spatial wave functions and their respective spinors in the pion. The modified quark geometry of the pion has considerable impact on the angular dependence of the annihilation mechanisms.

  9. Lattice study of the leptonic decay constant of the pion and its excitations

    Energy Technology Data Exchange (ETDEWEB)

    Mastropas, Ekaterina; Richard, David

    2014-11-01

    We present a calculation of the decay constant of the pion, and its lowest-lying three excitations, at three values of the pion mass between around 400 and 700 MeV, using anisotropic clover lattices. We use the variational method to determine an optimal interpolating operator for each of the states. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass.

  10. Determination of the negatively charged pion-proton scattering length from pionic hydrogen

    CERN Document Server

    Ericson, Torleif Eric Oskar; Wycech, S

    2003-01-01

    We derive a closed, model independent, expression for the electromagnetic correction factor to the hadronic scattering length extracted from a hydrogenic atom with an extended charge and in the limit of a short ranged hadronic interaction to terms of order ((alpha)**2)(log(alpha)) in the limit of a non-relativistic approach. A hadronic negatively charged pion-proton scattering length of 0.0870(5), in units of inverse charged pion-mass, is deduced, leading to a pion-nucleon coupling constant from the GMO relation equals to 14.00(19).

  11. Charge ratio of cosmic pions in the atmosphere

    CERN Document Server

    Bhattacharya, D P; Sarkar, K

    1977-01-01

    The CERN intersecting storage ring data on pp to pi /sup +or-/+X inclusive reactions can be represented by a single scaling variable eta =2p/sub T//sup 2/x/(c ln(s/s/sub 0/)), for 0.075pion spectrum at the top of the atmosphere has been estimated using this new type of scaling variable and the primary nucleon spectrum of Grigorov et al. (1971) has been used as a hadron source at the top of the atmosphere. (11 refs).

  12. Superluminal neutrinos at OPERA confront pion decay kinematics.

    Science.gov (United States)

    Cowsik, Ramanath; Nussinov, Shmuel; Sarkar, Utpal

    2011-12-16

    Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits α=(ν(ν)-c)/c<4×10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (ν-c)/c<10(-12). © 2011 American Physical Society

  13. Shear viscosity and entropy of a pion gas

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Jean-Bernard; Oliinychenko, Dmytro; Schaefer, Anna; Petersen, Hannah [FIAS, Goethe University, Frankfurt (Germany)

    2016-07-01

    A model of microscopic non-equilibrium dynamics for classical point particles is used to calculate the transport coefficients of dense hadronic matter. Specifically, the shear viscosity to entropy density ratio is investigated, and the temperature dependence between 100 MeV and 300 MeV is explored. Calculations are made at corresponding particle densities going from 0.01 to 0.34 in a pion box simulating infinite matter. The results for the entropy and shear viscosity are then compared to analytic estimates. In addition, massless particles as well as ρ-meson resonance excitations are included. This will be the starting point for the calculation of more transport coefficients as functions of T and μ{sub B}; expanding systems could also be considered.

  14. The A{sub 5} and the pion field

    Energy Technology Data Exchange (ETDEWEB)

    Hirn, Johannes [IFIC, Departament de Fisica Teorica, CSIC - Universitat de Valencia, Edifici d' Instituts de Paterna, Apt. Correus 22085, 46071 Valencia (Spain)], E-mail: johannes.hirn@ific.uv.es; Sanz, Veronica [CAFPE, Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, 18071 Granada (Spain)], E-mail: vsanz@ugr.es

    2007-02-15

    In this talk, an SU(N{sub f})xSU(N{sub f}) Yang-Mills model with a compact extra-dimension is used to describe the spin-1 mesons and pions of massless QCD in the large-N{sub c}. The right 4D symmetry and symmetry-breaking pattern is produced by imposing appropriate boundary conditions. The Goldstone boson (GB) fields are constructed using a Wilson line. We derive the low-energy limit (chiral lagrangian), discuss {rho}-meson dominance, sum rules between resonance couplings and the relation with the QCD high-energy behavior. Finally, we provide an analytic expression for the two-point function of vector and axial currents.

  15. Mean pion multiplicities in Ar+Sc collisions

    CERN Document Server

    Naskręt, Michał

    2016-01-01

    Preliminary results for mean negatively charged pion multiplicities $\\langle \\pi^- \\rangle$ using the $h^-$ method are presented for central Ar+Sc collisions at 13, 19, 30, 40, 75 and 150\\textit{A} GeV/c beam momentum. The data were recorded by the NA61/SHINE detector at the CERN SPS. Starting with rapidity distributions ${dn}/{dy}$ the procedure of obtaining total multiplicities is presented. The mean number of wounded nucleons $\\langle W\\rangle$ extracted from the Glissando MC model is used to calculate the ratio $\\langle \\pi^- \\rangle/\\langle W\\rangle.$ The results are compared to those from other experiments and their dependence on colliding systems and collision energy is discussed.

  16. Off-shell persistence of composite pions and kaons

    Science.gov (United States)

    Qin, Si-Xue; Chen, Chen; Mezrag, Cédric; Roberts, Craig D.

    2018-01-01

    In order for a Sullivan-like process to provide reliable access to a meson target as t becomes spacelike, the pole associated with that meson should remain the dominant feature of the quark-antiquark scattering matrix and the wave function describing the related correlation must evolve slowly and smoothly. Using continuum methods for the strong-interaction bound-state problem, we explore and delineate the circumstances under which these conditions are satisfied: for the pion, this requires -t ≲0.6 GeV2 , whereas -t ≲0.9 GeV2 will suffice for the kaon. These results should prove useful in planning and evaluating the potential of numerous experiments at existing and proposed facilities.

  17. Measurement of Charged Pions from Neutrino-produced Nuclear Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Clifford N. [Univ. of California, Irvine, CA (United States)

    2014-01-01

    A method for identifying stopped pions in a high-resolution scintillator bar detector is presented. I apply my technique to measure the axial mass MΔAfor production of the Δ(1232) resonance by neutrino, with the result MΔA = 1.16±0.20 GeV (68% CL) (limited by statistics). The result is produced from the measured spectrum of reconstructed momentum-transfer Q2. I proceed by varying the value of MΔA in a Rein-Sehgal-based Monte Carlo to produce the best agreement, using shape only (not normalization). The consistency of this result with recent reanalyses of previous bubble-chamber experiments is discussed.

  18. Two-Pion Production in Nucleon-Nucleon Collisions

    Science.gov (United States)

    Clement, Heinz; Brodowski, W.; Bilger, R.; Calén, H.; Clement, H.; Ekström, C.; Fransson, K.; Greiff, J.; Häggström, S.; Höistad, B.; Johanson, J.; Johansson, A.; Johansson, T.; Kilian, K.; Kullander, S.; Kupść, A.; Marciniewski, P.; Morosov, B.; Oelert, W.; Pätzold, J.; Ruber, R. J. M. Y.; Schepkin, M.; Scobel, W.; Seluzhenkov, I.; Stepaniak, J.; Sukhanov, A.; Turowiecki, A.; Wagner, G. J.; Wilhelmi, Z.; Zabierowski, J.; Zlomanczuk, J.

    2003-01-01

    Measurements of the two-pion production near threshold have been carried out at CELSIUS with the PROMICE-WASA detector for the channels pp → pnπ+π0, pp → ppπ0π0 and pp → ppπ+π-. For the latter channel the first exclusive data of solid statistics have been obtained. Within a conventional interpretation of the reaction mechanism they reveal pp → pp*(1440) → ppσ → pp(π+π-)I=ℓ=0 as the dominant process as well as significant contributions from p*(1440) → Δπ → p(π+π-)I=ℓ=0. The observed anisotropy in the proton angular distribution is consistent with heavy-meson exchange between the colliding nucleons.

  19. Scattering phase shift for elastic two pion scattering and the rho resonance in lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Gutzwiller, Simone

    2012-10-08

    In this thesis we use lattice QCD to compute scattering phase shifts for elastic two-pion scattering in the isospin I=1 channel. Using Luescher's formalism, we derive the scattering phase shifts for different total momenta of the two-pion system in a non-rest frame. Furthermore we analyse the symmetries of the non-rest frame lattices and construct 2-pion and rho operators transforming in accordance with these symmetries. The data was collected for a 32{sup 3} x 64 and a 40{sup 3} x 64 lattice with N{sub f}=2 clover improved Wilson fermions at a pion mass around 290 MeV and a lattice spacing of about 0.072 fm.

  20. New high precision data on the differential cross sections of the pion-proton elastic scattering

    Directory of Open Access Journals (Sweden)

    Alekseev I. G.

    2014-01-01

    Full Text Available The EPECUR collaboration presents new high precision data on the pion-proton elastic scattering in the second resonance region. The experiment EPECUR is placed on the universal beam channel of the accelerator ITEP. The setup features 0.1% beam pion momentum tagging system, 25 cm long liquid hydrogen target, placed in mylar container and beryllium outer shell, low material wire drift chambers and high performance DAQ. More than 3 billions of triggers have been collected. The data cover pion beam momentum range 0.8 - 1.3 GeV/c and 40-120 degrees center-of-mass scattering angle range for both positive and negative pions. The measured differential cross section has 2% statistical accuracy in 2 degrees angle and 5 MeV/c momentum intervals.

  1. Search for neutrino charged current coherent pion production at SciBooNE

    CERN Document Server

    Hiraide, K

    2009-01-01

    SciBooNE is a neutrino experiment measuring the neutrino cross sections on carbon in the one GeV region. We have performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, \

  2. Pion Structure in Qcd: from Theory to Lattice to Experimental Data

    Science.gov (United States)

    Bakulev, A. P.; Mikhailov, S. V.; Pimikov, A. V.; Stefanis, N. G.

    We describe the present status of the pion distribution amplitude (DA) as it originates from several sources: (i) a nonperturbative approach based on QCD sum rules with nonlocal condensates, (ii) an O(as) QCD analysis of the CLEO data on Fgg*p(Q2) with asymptotic and renormalon models for higher twists and (iii) recent high-precision lattice QCD calculations of the second moment of the pion DA. We show predictions for the pion electromagnetic form factor, obtained in analytic QCD perturbation theory, and compare it with the JLab data on Fp(Q2). We also discuss in this context an improved model for nonlocal condensates in QCD and show its consequences for the pion DA and the gg*p transition form factor. We include a brief analysis of meson-induced massive lepton (muon) Drell-Yan production for the process p-Nm+m-X, considering both an unpolarized nucleon target and longitudinally polarized protons.

  3. 750 GeV dark pion: Cousin of a dark G -parity odd WIMP

    Science.gov (United States)

    Bai, Yang; Berger, Joshua; Lu, Ran

    2016-04-01

    We point out a potential common origin of the recently observed 750 GeV diphoton resonance and a weakly interacting massive particle (WIMP) candidate. In a dark QCD sector with an unbroken dark G parity, the diphoton resonance could be a dark G -even pion, while the WIMP could be the lightest dark G -odd pion. Both particles are Standard Model gauge singlets and have the same decay constant. For the dark pion decay constant of around 500 GeV, both the diphoton excess at the LHC and the dark matter thermal abundance can be accommodated in our model. Our model predicts additional dark G -even and dark G -odd color-octet pions within reach of the 13 TeV LHC runs. For the 5 +5 ¯ model, compatible with the grand unified theories, the WIMP mass is predicted to be within (613,750) GeV.

  4. Minkowski space pion model inspired by lattice QCD running quark mass

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Clayton S. [Instituto Tecnológico de Aeronáutica, DCTA, 12.228-900 São José dos Campos, SP (Brazil); Melo, J.P.B.C. de [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo, SP (Brazil); Frederico, T., E-mail: tobias@ita.br [Instituto Tecnológico de Aeronáutica, DCTA, 12.228-900 São José dos Campos, SP (Brazil)

    2017-03-10

    The pion structure in Minkowski space is described in terms of an analytic model of the Bethe–Salpeter amplitude combined with Euclidean Lattice QCD results. The model is physically motivated to take into account the running quark mass, which is fitted to Lattice QCD data. The pion pseudoscalar vertex is associated to the quark mass function, as dictated by dynamical chiral symmetry breaking requirements in the limit of vanishing current quark mass. The quark propagator is analyzed in terms of a spectral representation, and it shows a violation of the positivity constraints. The integral representation of the pion Bethe–Salpeter amplitude is also built. The pion space-like electromagnetic form factor is calculated with a quark electromagnetic current, which satisfies the Ward–Takahashi identity to ensure current conservation. The results for the form factor and weak decay constant are found to be consistent with the experimental data.

  5. The coupling of heavy mesons to the pion on the lattice; Couplage des mesons lourds au pion sur reseau

    Energy Technology Data Exchange (ETDEWEB)

    Herdoiza, G

    2004-04-15

    The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)

  6. Measurement of Charged Current Coherent Pion Production by Neutrinos on Carbon at MINER$\

    Energy Technology Data Exchange (ETDEWEB)

    Mislivec, Aaron Robert [Univ. of Rochester, NY (United States)

    2017-01-01

    Neutrino-nucleus coherent pion production is a rare neutrino scattering process where the squared four-momentum transferred to the nucleus is small, a lepton and pion are produced in the forward direction, and the nucleus remains in its initial state. This process is an important background in neutrino oscillation experiments. Measurements of coherent pion production are needed to constrain models which are used to predict coherent pion production in oscillation experiments. This thesis reports measurements of νµ and νµ charged current coherent pion production on carbon for neutrino energies in the range 2 < Eν < 20 GeV. The measurements were made using data from MINERνA, which is a dedicated neutrino-nucleus scattering experiment that uses a fi scintillator tracking detector in the high-intensity NuMI neutrino beam at Fermilab. Coherent interactions were isolated from the data using only model-independent signatures of the reaction, which are a forward muon and pion, no evidence of nuclear breakup, and small four-momentum transfer to the nucleus. The measurements were compared to the coherent pion production model used by oscillation experiments. The data and model agree in the total interaction rate and are similar in the dependence of the interaction rate on the squared four- momentum transferred from the neutrino. The data and model disagree significantly in the pion kinematics. The measured νµ and νµ interaction rates are consistent, which supports model predictions that the neutrino and antineutrino interaction rates are equal.

  7. Pion double charge exchange at 50 MeV on /sup 14/C

    Energy Technology Data Exchange (ETDEWEB)

    Navon, I.; Leitch, M.J.; Bryman, D.A.; Numao, T.; Schlatter, P.; Azuelos, G.; Poutissou, R.; Burnham, R.A.; Hasinoff, M.; Poutissou, J.M.

    1984-01-09

    The first measurement of pion double charge exchange at low energy is reported. The reaction /sup 14/C(..pi../sup +/,..pi../sup -/) /sup 14/O was measured at an incident pion energy of 50 MeV. Differential cross sections of the double analog transition are given in the angular range 50/sup 0/--120/sup 0/. Strong nonanalog transitions were also observed.

  8. Research program in nuclear and solid state physics. [including pion absorption spectra and muon spin precession

    Science.gov (United States)

    1974-01-01

    The survey of negative pion absorption reactions on light and medium nuclei was continued. Muon spin precession was studied using an iron target. An impulse approximation model of the pion absorption process implied that the ion will absorb almost exclusively on nucleon pairs, single nucleon absorption being suppressed by energy and momentum conservation requirements. For measurements on both paramagnetic and ferromagnetic iron, the external magnetic field was supplied by a large C-type electromagnet carrying a current of about 100 amperes.

  9. Pion transverse-momentum spectrum and elliptic anisotropy of partially coherent source

    Science.gov (United States)

    Ru, Peng; Bary, Ghulam; Zhang, Wei-Ning

    2018-02-01

    In this letter, we study the pion momentum distribution of a coherent source and investigate the influences of coherent emission on the pion transverse-momentum (pT) spectrum and elliptic anisotropy. With a partially coherent source, constructed by a conventional viscous hydrodynamics model (chaotic part) and a parameterized expanding coherent source model, we reproduce the pion pT spectrum and elliptic anisotropy coefficient v2 (pT) in the peripheral Pb-Pb collisions at √{sNN } = 2.76 TeV. It is found that the influences of coherent emission on the pion pT spectrum and v2 (pT) are related to the initial size and shape of the coherent source, largely due to the interference effect. However, the effect of source dynamical evolution on coherent emission is relatively small. The results of the partially coherent source with 33% coherent emission and 67% chaotic emission are consistent with the experimental measurements of the pion pT spectrum, v2 (pT), and especially four-pion Bose-Einstein correlations.

  10. Determination of the pion-nucleon coupling constant and scattering lengths

    CERN Document Server

    Ericson, Torleif Eric Oskar; Thomas, A W

    2002-01-01

    We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...

  11. Pion-Photon Transition Form Factor and Pion Distribution Amplitude in QCD: Facing the Enigmatic Behavior of the BaBar Data

    Science.gov (United States)

    Stefanis, N. G.; Bakulev, A. P.; Mikhailov, S. V.; Pimikov, A. V.

    2012-04-01

    We present an extended analysis of the data for the pion-photon transition form factor from different experiments, CELLO, CLEO, and BaBar, and discuss various theoretical approaches which try to reason from them. We focus on the divergent behavior of the BaBar data for the pion and those for the η(η') pseudoscalar mesons and comment on recently proposed explanations for this discrepancy. We argue that it is not possible at present to accommodate these data within the standard QCD framework self-consistently.

  12. Pion-Photon Transition Form Factor and Pion Distribution Amplitude in QCD: Facing the Enigmatic Behavior of the BaBar Data

    Energy Technology Data Exchange (ETDEWEB)

    Stefanis, N.G. [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Bakulev, A.P., E-mail: stefanis@tp2.ruhr-uni-bochum.de [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Mikhailov, S.V.; Pimikov, A.V. [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation)

    2012-04-15

    We present an extended analysis of the data for the pion-photon transition form factor from different experiments, CELLO, CLEO, and BaBar, and discuss various theoretical approaches which try to reason from them. We focus on the divergent behavior of the BaBar data for the pion and those for the {eta}({eta}{sup Prime }) pseudoscalar mesons and comment on recently proposed explanations for this discrepancy. We argue that it is not possible at present to accommodate these data within the standard QCD framework self-consistently.

  13. Review of the NA48 CP violation measurements with neutral and charged kaons

    CERN Document Server

    Cenci, Patrizia

    2009-01-01

    The main results on the CP violation measurements with neutral and charged kaons from the NA48 experiment at the CERN SPS are reviewed in this paper. The direct CP violating parameter Re(ε′/ε) has been measured by NA48 from the decay rates of neutral kaons into pion pairs. The final result, based on the data collected in 1997, 1998, 1999 and 2001, clearly established the existence of direct CP violation. NA48 also measured the CP violation parameter |η+−|, defined as the amplitude ratio of CP violating to CP conserving neutral kaon decays into two charged pions: |η+−| = A(KL → π+π−)/A(KS → π+π−). The CP violating decay KS →π0π0π0 has been studied by the NA48/1 experiment, using the data taken in 2000 and 2002 with a KS beam at high intensity. Only direct CP violation occurs in charged kaon decays, since mixing is not allowed. NA48/2 measured the Dalitz plot asymmetry of K± →3π± decays from the data collected in 2003 and 2004, setting a new limit on the asymmetry in the decay ma...

  14. Study of neutral-charged particle correlations in high energy collisions

    CERN Document Server

    Dao, F T

    1973-01-01

    Recent experiments at Serpukhov, NAL, and CERN indicate a strong correlation between neutral and charged pions produced in high energy collisions, in contrast to the trend shown by data at lower energies. This study of the energy and charge dependence of these correlations indicates that they do not depend upon the initial state particles and that they are in reasonable agreement with the critical fluid gas model. These high energy correlation data are also studied in terms of a semi-inclusive Koba- Nielsen-Olesen scaling relation. (9 refs).

  15. Effect of the ηη channel and interference phenomena in the two-pion transitions of charmonia and bottomonia

    Directory of Open Access Journals (Sweden)

    Surovtsev Yu.S.

    2017-01-01

    Full Text Available The basic shape of di-pion mass spectra in the two-pion transitions of both charmonia and bottomonia states is explained by a unified mechanism based on contributions of the ππ, KK̅, and ηη coupled channels including their interference. The role of the individual f0 resonances in shaping the di-pion mass distributions in the charmonia and bottomonia decays is considered.

  16. Beam-spin Asymmetries from Semi-inclusive Pion Electroproduction

    Energy Technology Data Exchange (ETDEWEB)

    Gohn, Wesley P. [University of Connecticut, Storrs, CT (United States); Avakian, Harut A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Joo, Kyungseon [University of Connecticut, Storrs, CT (United States); Ungaro, Maurizio [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-04-01

    We have measured the moment A{sup sin{phi}}{sub LU} corresponding to the polarized electron beam-spin asymmetry in SIDIS. A{sup sin{phi}}{sub LU} is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (pi{sup +}, pi{sup 0} and pi{sup -}) were measured simultaneously over a large range of kinematics within the virtuality range Q{sup 2} ~ 1.0-4.5 GeV{sup 2}. The observable was measured with good statistical precision over a large range of z, P{sub T}, x{sub B}, and Q{sup 2}, which permits comparison with several reaction models. The discussed measurements provide an upgrade in statistics over previous measurements, and serve as the first evidence for the negative sign of the {pi}{sup -} sin{phi} Moment.

  17. Neutron Skin of Pb208 from Coherent Pion Photoproduction

    Science.gov (United States)

    Tarbert, C. M.; Watts, D. P.; Glazier, D. I.; Aguar, P.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Bekrenev, V.; Boillat, B.; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R.; Downie, E. J.; Foehl, K.; Grabmayr, P.; Gregor, R.; Heid, E.; Hornidge, D.; Jahn, O.; Kashevarov, V. L.; Knezevic, A.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Krambrich, D.; Krusche, B.; Lang, M.; Lisin, V.; Livingston, K.; Lugert, S.; MacGregor, I. J. D.; Manley, D. M.; Martinez, M.; McGeorge, J. C.; Mekterovic, D.; Metag, V.; Nefkens, B. M. K.; Nikolaev, A.; Novotny, R.; Owens, R. O.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Price, J. W.; Rosner, G.; Rost, M.; Rostomyan, T.; Schadmand, S.; Schumann, S.; Sober, D.; Starostin, A.; Supek, I.; Thomas, A.; Unverzagt, M.; Walcher, Th.; Zana, L.; Zehr, F.; Crystal Ball at MAMI; A2 Collaboration

    2014-06-01

    Information on the size and shape of the neutron skin on Pb208 is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be cn=6.70±0.03(stat.) fm and an=0.55±0.01(stat.)-0.03+0.02(sys.) fm, respectively, corresponding to a neutron skin thickness Δrnp=0.15±0.03(stat.)-0.03+0.01(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of Pb208 has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.

  18. Pion femtoscopy measurements in ALICE at the LHC

    CERN Document Server

    Graczykowski, Łukasz Kamil

    2014-01-01

    We present the results of two-pion Bose-Einstein correlations measured in Pb--Pb collisions at a center-of-mass energy sqrt(s_NN) = 2.76 TeV recorded by ALICE at the Large Hadron Collider. These types of correlations allow to extract, using the technique of femtoscopy (also known as Hanburry-Brown Twiss interferometry, or shortly HBT), the space-time characteristics of the source from the correlation calculated as a function of the pair momentum difference. The femtoscopic analysis was performed using both the Spherical Harmonics decomposition and the standard 3D Cartesian representation of the correlation function. The source sizes in three dimensions, the HBT radii, were extracted by fitting the experimental correlation functions. The resulting dependencies of the radii as a function of centrality and pair transverse momentum are shown. The results indicate the existence of a flowing medium and provide constraints on existing dynamical models. The ALICE Pb-Pb HBT radii are also compared to the pp analysis a...

  19. Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor

    CERN Document Server

    Huber, G M; Horn, T; Beise, E J; Gaskell, D; Mack, D J; Tadevosyan, V; Volmer, J; Abbott, D; Aniol, K; Anklin, H; Armstrong, C; Arrington, J; Assamagan, K; Avery, S; Baker, O K; Barrett, B; Bochna, C; Boeglin, W; Brash, E J; Breuer, H; Chang, C C; Chant, N; Christy, M E; Dunne, J; Eden, T; Ent, R; Gibson, E; Gilman, R; Gustafsson, K; Hinton, W; Holt, R J; Jackson, H; Jin, S; Jones, M K; Keppel, C E; Kim, P H; Kim, W; King, P M; Klein, A; Koltenuk, D; Kovaltchouk, V; Kiang, M; Liu, J; Lolos, G J; Lung, A; Margaziotis, D J; Markowitz, P; Matsumura, A; McKee, D; Meekins, D; Mitchell, J; Miyoshi, T; Mkrtchyan, H; Müller, B; Niculescu, G; Niculescu, I; Okayasu, Y; Pentchev, L; Perdrisat, C; Pitz, D; Potterveld, D; Punjabi, V; Qin, L M; Reimer, P; Reinhold, J; Roche, J; Roos, P G; Sarty, A; Shin, I K; Smith, G R; Stepanyan, S; Tang, L G; Tvaskis, V; Van der Meer, R L J; Vansyoc, K; Van Westrum, D; Vidakovic, S; Vulcan, W; Warren, G; Wood, S A; Xu, C; Yan, C; Zhao, W -X; Zheng, X; Zihlmann, B

    2008-01-01

    The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime.

  20. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. II. Determination of, and results for, the pion form factor

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Garth; Blok, Henk; Horn, Tanja; Beise, Elizabeth; Gaskell, David; Mack, David; Tadevosyan, Vardan; Volmer, Jochen; Abbott, David; Aniol, Konrad; Anklin, Heinz; Armstrong, Christopher; Arrington, John; Assamagan, Ketevi; Avery, Steven; Baker, O.; Barrett, Robert; Bochna, Christopher; Boeglin, Werner; Brash, Edward; Breuer, Herbert; Chang, C.; Chang, C.C.; Chant, Nicholas; Christy, Michael; Dunne, James; Eden, Thomas; Ent, Rolf; Fenker, Benjamin; Gibson, Edward; Gilman, Ronald; Gustafsson, Kenneth; Hinton, Wendy; Holt, Roy; Jackson, Harold; uk Jin, Seong; Jones, Mark; Keppel, Cynthia; Kim, pyunghun; Kim, Wooyoung; King, Paul; Klein, Andreas; Koltenuk, Douglas; Kovaltchouk, Vitali; Liang, Meihua; Liu, Jinghua; Lolos, George; Lung, Allison; Margaziotis, Demetrius; Markowitz, Pete; Matsumura, Akihiko; McKee, David; Meekins, David; Mitchell, Joseph; Miyoshi, Toshinobu; Mkrtchyan, Hamlet; Mueller, Robert; Niculescu, Gabriel; Niculescu, Maria-Ioana; Okayasu, Yuichi; Pentchev, Lubomir; Perdrisat, Charles; Pitz, David; Potterveld, David; Punjabi, Vina; Qin, Liming; Reimer, Paul; Reinhold, Joerg; Roche, Julie; Roos, Philip; Sarty, Adam; Shin, Ilkyoung; Smith, Gregory; Stepanyan, Stepan; Tang, Liguang; Tvaskis, Vladas; van der Meer, Rob; Vansyoc, Kelley; Van Westrum, Derek; Vidakovic, Sandra; Vulcan, William; Warren, Glen; Wood, Stephen; Xu, Chen; Yan, Chen; Zhao, Wenxia; Zheng, Xiaochao; Zihlmann, Benedikt

    2008-10-01

    DOI: http://dx.doi.org/10.1103/PhysRevC.78.045203
    The charged pion form factor, Fpi(Q2), is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q2=0.60-2.45 GeV2. Above Q2=1.5 GeV2, the Fpi values are systematically below the monopole parametrization that describes the low Q2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard c

  1. CO2-Neutral Fuels

    NARCIS (Netherlands)

    Goede, A.; van de Sanden, M. C. M.

    2016-01-01

    Mimicking the biogeochemical cycle of System Earth, synthetic hydrocarbon fuels are produced from recycled CO2 and H2O powered by renewable energy. Recapturing CO2 after use closes the carbon cycle, rendering the fuel cycle CO2 neutral. Non-equilibrium molecular CO2 vibrations are key to high energy

  2. Bleach Neutralizes Mold Allergens

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  3. Modeling thermospheric neutral density

    Science.gov (United States)

    Qian, Liying

    Satellite drag prediction requires determination of thermospheric neutral density. The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) and the global-mean Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM) were used to quantify thermospheric neutral density and its variations, focusing on annual/semiannual variation, the effect of using measured solar irradiance on model calculations of solar-cycle variation, and global change in the thermosphere. Satellite drag data and the MSIS00 empirical model were utilized to compare to the TIEGCM simulations. The TIEGCM simulations indicated that eddy diffusion and its annual/semiannual variation is a mechanism for annual/semiannual density variation in the thermosphere. It was found that eddy diffusion near the turbopause can effectively influence thermospheric neutral density. Eddy diffusion, together with annual insolation variation and large-scale circulation, generated global annual/semiannual density variation observed by satellite drag. Using measured solar irradiance as solar input for the TIEGCM improved the solar-cycle dependency of the density calculation shown in F10.7 -based thermospheric empirical models. It has been found that the empirical models overestimate density at low solar activity. The TIEGCM simulations did not show such solar-cycle dependency. Using historic measurements of CO2 and F 10.7, simulations of the global-mean TIMEGCM showed that thermospheric neutral density at 400 km had an average long-term decrease of 1.7% per decade from 1970 to 2000. A forecast of density decrease for solar cycle 24 suggested that thermospheric density will decrease at 400 km from present to the end of solar cycle 24 at a rate of 2.7% per decade. Reduction in thermospheric density causes less atmospheric drag on earth-orbiting space objects. The implication of this long-term decrease of thermospheric neutral density is that it will increase the

  4. Neutral pion measurement in p-Pb collisions at ${\\sqrt{s_{\\rm{NN}}}}$ = 5.02 TeV

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00508134

    Quarks and gluons which are thought to be a elementary particle are confined in the nucleon, and it is impossible to extract only quark from the nucleon. However they are freed from confined state with a condition of extreme high temperature and high density. There was the high temperature and dense condition immediately after the big bang of the birth of the universe, and quarks and gluons could move around freely. This state is called Quark-Gluon Plasma (QGP). A high-energy heavy-ion collisions experiment can create the QGP experimentally. Particles passing through the QGP lose energy by the strong force. In the results, produced particles are modified their own yields. Strong suppression of high-${p_{\\rm T}}$ particles has been observed in heavy-ion collisions at LHC energies, which can be interpreted by invoking various processes involving transport properties of the QCD medium and initial-state effects. Proton-nucleus (p-A) collisions are intermediate between proton-proton (pp) and nucleus-nucleus (A-A)...

  5. Measurement of a Neutrino-Induced Charged Current Single Neutral Pion Cross Section at MicroBooNE

    Energy Technology Data Exchange (ETDEWEB)

    Hackenburg, Ariana [Yale U.

    2018-01-01

    Micro Booster Neutrino Experiment (MicroBooNE) is a Liquid Argon Time Projection Chamber (LArTPC) operating in the Booster Neutrino Beamline at Fermi National Accelerator Laboratory. MicroBooNE's physics goals include studying short basline $\

  6. Photon and neutral pion production in Au+Au collisions at sqrt(s_{NN}) = 130 GeV

    CERN Document Server

    Adams, J; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevshchikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Yu; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gutíerrez, T D; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F J M; Ghazikhanian, V; Ghosh, P; González, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D P; Guedon, M; Guertin, S M; Sen-Gupta, A; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang Sheng Li; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Krämer, M; Kravtsov, P; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Leontiev, V M; Le Vine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Mora-Corral, M J; Morozov, V; Moura; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevozchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schröder, L S; Schweda, K; Seger, J; Seliverstov, D M; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimansky, S S; Singaraju, R N; Simon, F; Skoro, G P; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Struck, C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; Van der Molen, A M; Vasilev, A N; Vasilev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevsky, Yu V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zolnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N

    2004-01-01

    We report the first inclusive photon measurements about mid-rapidity (|y| photon photon decay channel. The fractional contribution of the pi0 -> photon photon decay to the inclusive photon spectrum decreases by 20% +/- 5% between pt = 1.65 GeV/c and pt = 2.4 GeV/c in the most central events, indicating that relative to pi0 -> photon photon decay the contribution of other photon sources is substantially increasing.

  7. An Upper limit on the neutral $B_s$ meson decays to charged $D_s$ meson pion branching ratio

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Michael Collins [Brandeis Univ., Waltham, MA (United States)

    2003-01-01

    This thesis reports the results of a study of B → Dπ decays. The analysis is performed on 110 pb-1 of data collected by CDF at the Fermi National Accelerator Laboratory between 1992 and 1995.

  8. Direct Photon Shine: Direct Photon And Neutral Pion Production In Center Of Mass Energy = 200 Gev Gold+gold Collisions

    CERN Document Server

    Frantz, J

    2005-01-01

    With substantial additional statistics due to the inclusion of a new Run2 trigger data sample, the PHENIX Collaboration has measured the first positive direct photon (γdirect) signal in Au+Au collisions at sNN = 200 GeV and midrapidity (|y| ≤ 0.35). The measurement is made in 10 centrality bins covering 0–92% of the full geometric cross section. Additionally, the new data has extended the previous PHENIX π 0 measurement [70] by 4 GeV/c in its pT range, matching the γdirect measurement with a pT range of 1–14 GeV/c which make them the highest pT measurements yet in RHIC Au+Au. The γdirect yields are compared amongst themselves, with references, and with the π 0. The suppression in meson hard scattering previously discovered at RHIC [70] is found to be absent in the direct photons. Specifically, using the NLO perturbative QCD prediction of γdirect as a reference, the nuclear modification factor RAA is found to be consistent wit...

  9. Measurement Of The Neutral Lambda-bottom Decaying To Positive Lambda-charm Negavtive Pion Branching Ratio

    CERN Document Server

    Le, Y

    2004-01-01

    We present a measurement of the L0b→L+ cp- branching ratio in pp¯ collisions at s = 1.96 TeV using 65 pb−1 data collected by the Collider Detector at FermiLab (CDF). The measurement starts from reconstructing two decay modes: L0b→L+ cp-,where L+c→p K- p+ B&d1;0→D+ p-,where D+→p+K- p +. We obtained 96 ± 13 L0b and 321 ± 22 B¯0 candidates from the CDF Run II Two-Track Hadronic Trigger data sample. The relative branching ratio of the two decays is then measured based on the equation: fLbfd BRLb→L +cp- BRB&d1;0 →D+p- =BRD+→Kpp BRL+ c→pKp NLbNB&d1; 0eB&d1; 0eLb . The measurement gives fLbfd BRLb→L +cp- BRB&d1;0 →D+p- =0.66±0.11stat ±0.09syst ±0.18BR . The L0b→L+ cp- branching ratio is then extracted, giving BRL0 b→L+cp- =6.6±1.2 stat.±0.9 syst.&plus...

  10. Dispersion relation for hadronic light-by-light scattering: two-pion contributions

    Science.gov (United States)

    Colangelo, Gilberto; Hoferichter, Martin; Procura, Massimiliano; Stoffer, Peter

    2017-04-01

    In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic moment of the muon ( g - 2) μ , including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. As a by-product, we obtain a set of sum rules that could be used to constrain future calculations of γ ∗ γ ∗ → ππ. We validate the formalism extensively using the pion-box contribution, defined by two-pion intermediate states with a pion-pole left-hand cut, and demonstrate how the full known result is reproduced when resumming the partial waves. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box, a μ π - box = - 15.9(2) × 10- 11. As an application of the partial-wave formalism, we present a first calculation of ππ-rescattering effects in HLbL scattering, with γ ∗ γ ∗ → ππ helicity partial waves constructed dispersively using ππ phase shifts derived from the inverse-amplitude method. In this way, the isospin-0 part of our calculation can be interpreted as the contribution of the f 0(500) to HLbL scattering in ( g - 2) μ . We argue that the contribution due to charged-pion rescattering implements corrections related to the corresponding pion polarizability and show that these are moderate. Our final result for the sum of pion-box contribution and its S-wave rescattering corrections reads a μ π - box + a μ, J = 0 ππ, π - pole LHC = - 24(1) × 10- 11.

  11. Re-evaluation of the relative decay rate of long-lived and short-lived neutral kaons into two neutral pions

    CERN Document Server

    Heeren, U

    1972-01-01

    Some time ago the CP-violating decay K/sub L//sup 0/ to pi /sup 0/ pi /sup 0/ was discovered by a CERN-RHEL-Aachen group, using a multiplate spark chamber arrangement near a K/sub L//sup 0/ beam, derived from the CERN proton synchrotron. These data have been reanalysed performing a least-squares fit to each event. The average errors of directions and energies of the detected photons have been experimentally determined on samples of 4-shower and 6-shower events. A normalization on regenerated K/sub s//sup 0/ to 2 pi /sup 0/ decays has been used. The value of mod eta /sub 00/ mod = mod A(K/sub L//sup 0/ to 2 pi /sup 0/)/A(K/sub s//sup 0/ to 2 pi /sup 0/) mod = (2.4+or-0.5).10/sup -3/ is consistent with T violation and CPT conservation in K/sub L//sup 0/ to 2 pi decay and with the existence of a superweak interaction. (32 refs).

  12. Combination therapy with pions and sizofiran for murine B-16 melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Takai, Yoshihiro; Sakamoto, Kiyohiko (Tohoku Univ., Sendai (Japan). School of Medicine); Goodman, G.B.

    1991-09-01

    B-16 melanoma transplanted into C57BL/6 mice was used to investigate the antitumor effect of Sizofiran (SPG) when applied alone and in combination with local irradiation using pions with 4 dose fractions of 2 Gy or 6 Gy each. SPG was given intramuscularly in a daily dose of 10 mg/kg for 25 consecutive days from day 4 after the initiation of irradiation, and thereafter three times a week up to day 45. The antitumor effect was evaluated by the changes in tumor volume, survival, the size of metastatic lymph nodes grossly involved, and pulmonary metastatic nodules on the surface of the lungs. After 24 Gy, significant differences were found between the group treated with combined pions and SPG, and the group treated with pions alone in terms of tumor volume change, survival and lymph node, pulmonary metastases. The number of tumor cells eradicated by host-mediated immune response enhanced by SPG was estimated from tumor regrowth curve to be about 10 cells. However, when SPG was applied to non-irradiated tumors or to tumors irradiated with only 8 Gy, it had neither antitumor nor life prolonging effect. From the present study, it seems that a SPG, as a biological response modifier, has some adjuvant effect only where a limited number of tumor cells remain following pion irradiation. Combination therapy using SPG may, therefore, be advantageous for patients with complete response or good partial response to pion irradiation. (author).

  13. Pion distribution amplitude extracted from the experimental data with the local duality sum rule

    Science.gov (United States)

    Guo, Ze-Kun; Liu, Jueping

    2008-10-01

    The photon-to-pion transition form factor is investigated using the form of the renormalon-based twist-four pion distribution amplitude (DA) in the framework of the light-cone local-duality QCD sum rule, which, with suitable parameters, is insensitive to the higher-order Gegenbauer coefficients. With a careful determination for the insertion parameters so that the contribution from the higher-order Gegenbauer expansions is suppressed, the best-fit central values of the first two nontrivial Gegenbauer coefficients of the pion distribution amplitude are extracted out from the CLEO data to be a2(1GeV2)=0.145±0.055 and a4(1GeV2)=-(0.125±0.085), respectively. The rescaled photon-to-pion transition form factor with our best-fit parameters is consistent very well with both the CELLO data and the prediction of the interpolation formula in all the experimental accessible region of the momentum transfer. The shape of the pion distribution amplitude based on the two-parameter model favors the camel-like type, where the near-end-point values are suppressed more than the asymptotic DA, and satisfies the midpoint constraint from light-cone sum rules approximately.

  14. CLEO and E791 data: a smoking gun for the pion distribution amplitude?

    Energy Technology Data Exchange (ETDEWEB)

    Bakulev, A.P.; Mikhailov, S.V.; Stefanis, N.G

    2004-01-01

    The CLEO experimental data on the {pi}{gamma} transition are analyzed to next-to-leading order accuracy in QCD perturbation theory using light-cone QCD sum rules. By processing these data along the lines proposed by Schmedding and Yakovlev, and recently revised by us, we obtain new constraints for the Gegenbauer coefficients a{sub 2} and a{sub 4}, as well as for the inverse moment {sub {pi}} of the pion distribution amplitude (DA). The former determine the pion DA at low momentum scale, the latter is crucial in calculating pion form factors. From the results of our analysis we conclude that the data confirm the end-point suppressed shape of the pion DA we previously obtained with QCD sum rules and nonlocal condensates, while the exclusion of both the asymptotic and the Chernyak-Zhitnitsky DAs is reinforced at the 3{sigma}- and 4{sigma}-level, respectively. The reliability of the main results of our updated CLEO data analysis is demonstrated. Our pion DA is checked against the di-jets data from the E791 experiment, providing credible evidence for our results far more broadly.

  15. CLEO and E791 Data A Smoking Gun for the Pion Distribution Amplitude?

    CERN Document Server

    Bakulev, A P; Stefanis, N G

    2003-01-01

    The CLEO experimental data on the \\pi\\gamma transition are analyzed to NLO in QCD perturbation theory using light-cone QCD sum rules. By processing the data along the lines proposed by Khodjamiryan, Schmedding and Yakovlev, and recently revised by us, we obtain new constraints for the Gegenbauer coefficients a_2 and a_4, as well as for the inverse moment \\langle{x^{-1}\\rangle of the pion distribution amplitude (DA). The former determine the pion DA at low momentum scale, the latter is crucial in calculating pion form factors. From the results of our analysis we conclude that the data confirm the shape of the pion DA we previously obtained with QCD sum rules and nonlocal condensates, while the exclusion of the asymptotic and the Chernyak-Zhitnitsky DA is reinforced. We also investigate the sensitivity of the calculated coefficients in this analysis to the twist-4 contribution and check out pion DA against the di-jets data of the E791 experiment, providing credible evidence for our results far more broadly. Thu...

  16. Nuclear Counter Effect and Pion-Electron misidentification Simulations and 1998 test beam results

    CERN Document Server

    Dittmar, Michael

    1999-01-01

    The electron/charged pion discrimination within the ECAL is investigated using GEANT simulations and the 1998 test beam results. The Nuclear Counter Effect within the Avalanche Photo-Diodes enhances the probability of an electron misidentification. The test beam data show a Nuclear Counter Effect with a mean value of about 450 MeV for a Minimum Ionizing Particle crossing the APD, instead of the expected 200-250 MeV for a readout with a single APD. This value can be explained with the inefficient connection between crystals and APD`s in the PROTO 97 set-up. The pion beam data show a long tail in the E/p-ratio, which can be reproduced by GEANT simulations with Nuclear Counter Effect. GEANT simulations are then used for a study of the pion-electron confusion with the expected Nuclear Counter Effect and the foreseen set-up with two APD`s per crystal. These simulations show that the tail in the pion-energy deposition is still present. As a result one expects that about 0.1 % of the pions with 10 GeV < E &am...

  17. Refinement of the Pion PDF implementing Drell-Yan and Deep Inelastic Scattering Experimental Data

    Science.gov (United States)

    Barry, Patrick; Sato, Nobuo; Melnitchouk, Wally; Ji, Chueng-Ryong

    2017-09-01

    We realize that an abundance of ``sea'' quarks and gluons (as opposed to three valence quarks) is crucial to understanding the mass and internal structure of the proton. An effective pion cloud exists around the core valence structure. In the Drell-Yan (DY) process, two hadrons collide, one donating a quark and the other donating an antiquark. The quark-antiquark pair annihilate, forming a virtual photon, which creates a lepton-antilepton pair. By measuring their cross-sections, we obtain information about the parton distribution function (PDF) of the hadrons. The PDF is the probability of finding a parton at a momentum fraction of the hadron, x, between 0 and 1. Complementary to the DY process is deep inelastic scattering (DIS). Here, a target nucleon is probed by a lepton, and we investigate the pion cloud of the nucleon. The experiments H1 and ZEUS done at HERA at DESY collect DIS data by detecting a leading neutron (LN). By using nested sampling to generate sets of parameters, we present some preliminary fits of pion PDFs to DY (Fermilab-E615 and CERN-NA10) and LN (H1 and ZEUS) datasets. We aim to perform a full NLO QCD global analysis to determine pion PDFs accurately for all x. There have been no attempts to fit the pion PDF using both low and high x data until now.

  18. Mod en neutral seksualitet!

    DEFF Research Database (Denmark)

    Leer, Jonatan

    2013-01-01

    Towards a Neutral Sexuality! or Roland Barthes as a Queer Thinker? This article argues that the work of Roland Barthes has interesting perspectives in common with the queer theory. This argument will be put forward by using his concept of ‘the neutral’ that Barthes defines as “that which outplays...... the paradigm”. This notion was presented at a series of lectures at Collège de France in 1977. Through a reading of Barthes’s autobiography, Roland Barthes par Roland Barthes (1975), the article demonstrates how Barthes in this text tries to outplay the paradigms that rules over the hegemonic understanding...... of gender and sexuality; also the fragmented text presents a vision of a sexual utopia, a neutral sexuality, that tries – like the queer theory – to go and think beyond a binary conception of gender and sexuality. Finally, it is suggested that we should start to think about a movement of “French queer...

  19. Gargamelle: neutral current event

    CERN Multimedia

    1973-01-01

    This event shows real tracks of particles from the 1200 litre Gargamelle bubble chamber that ran on the PS from 1970 to 1976 and on the SPS from 1976 to 1979. In this image a neutrino passes close to a nucleon and reemerges as a neutrino. Such events are called neutral curent, as they are mediated by the Z0 boson which has no electric charge.

  20. Exercise Equipment: Neutral Buoyancy

    Science.gov (United States)

    Shackelford, Linda; Valle, Paul

    2016-01-01

    Load Bearing Equipment for Neutral Buoyancy (LBE-NB) is an exercise frame that holds two exercising subjects in position as they apply counter forces to each other for lower extremity and spine loading resistance exercises. Resistance exercise prevents bone loss on ISS, but the ISS equipment is too massive for use in exploration craft. Integrating the human into the load directing, load generating, and motion control functions of the exercise equipment generates safe exercise loads with less equipment mass and volume.

  1. Beam Spin Asymmetry Measurements for Two Pion Photoproduction at CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark D. [Univ. of Glasgow, Scotland (United Kingdom)

    2015-09-01

    The overarching goal of this analysis, and many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (tau = 1x10-23 s) and often have very similar masses, it is often impossible to directly observe resonances in the excitation spectra of nucleons. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel pgamma p --> p π+ π-focusing on the intermediate mesonic states rho^0 and f^0, and the final state pions. The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables including those presented here. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis is presented and the resulting measurements.

  2. Photon-pion transition form factor at high photon virtualities within the nonlocal chiral quark model

    Science.gov (United States)

    Dorokhov, A. E.

    2010-11-01

    Recently, the BABAR collaboration reported the measurements of the photon-pion transition form factor F πγγ*( Q 2), which are in strong contradiction to the predictions of the standard factorization approach to perturbative QCD. In the present work, based on a nonperturbative approach to the QCD vacuum and on rather universal assumptions, we show that there exist two asymptotic regimes for the pion transition form factor. One regime with the asymptotic behavior F πγ*γ( Q 2) ˜ 1/ Q 2 corresponds to the result of the standard QCD factorization approach, while other violates the standard factorization and leads to asymptotic behavior as F πγ*γ( Q 2) ˜ ln( Q 2)/ Q 2. Furthermore, considering specific nonlocal chiral quark models, we find the region of parameters, where the existing CELLO, CLEO and BABAR data for the pion transition form factor are successfully described.

  3. Pion-photon transition form factor in light-cone sum rules

    Science.gov (United States)

    Pimikov, A. V.; Bakulev, A. P.; Mikhailov, S. V.; Stefanis, N. G.

    2012-10-01

    We extract constraints on the pion distribution amplitude from available data on the pionphoton transition form factor in the framework of light-cone sum rules. A pronounced discrepancy (2.7 - 3)σ between the Gegenbauer expansion coefficients extracted from the CELLO, CLEO, and Belle experimental data relative to those from BaBar is found. Predictions for the pion-photon transition form factor are presented by employing a pion distribution amplitude obtained long ago from QCD sum rules with nonlocal condensates. These predictions comply with the Belle data but disagree with those of BaBar beyond 9 GeV2. This original article was incorrectly published with a corrupt version of Fig. 1. The corrigendum (which is attached to this article) includes the correct version of the figure.

  4. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, I.G.; Budkovsky, P.E.; Kanavets, V.P.; Koroleva, L.I.; Morozov, B.V.; Nesterov, V.M.; Ryltsov, V.V.; Sulimov, A.D.; Svirida, D.N. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bazhanov, N.A.; Bunyatova, E.I.; Zolin, L.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Beloglazov, Yu.A.; Filimonov, E.A.; Kovalev, A.I.; Novinsky, D.V.; Shchedrov, V.A.; Sumachev, V.V.; Trautman, V.Yu. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)

    2009-02-15

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of {theta}{sub CM}{approx}150-170 at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years. (orig.)

  5. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    Science.gov (United States)

    Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.; Sumachev, V. V.; Svirida, D. N.; Trautman, V. Yu.; Zolin, L. S.

    2009-02-01

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of θ_{CM}^{} ≈ 150 - 170° at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years.

  6. Towards extracting the timelike pion form factor on CLS 2-flavour ensembles

    CERN Document Server

    Erben, Felix; Mohler, Daniel; Wittig, Hartmut

    2016-01-01

    Results are presented from an ongoing study of the $\\rho$ resonance. We use the distillation approach in order to create correlator matrices involving $\\rho$ and $\\pi\\pi$ interpolators. The study is done in a centre-of-mass frame and several moving frames. We are able to extract energy levels by solving the GEVP of those correlator matrices. The initial exploratory study is being done on a CLS 2-flavour lattice with a pion mass of $451$ $\\mathrm{MeV}$ using $\\mathcal{O}(a)$ improved Wilson fermions. One aim of this work is to extract the timelike pion form factor after applying the L\\"uscher formalism. We also plan to integrate this study with the existing Mainz programme for the calculation of the hadronic vacuum polarization contribution to the muon $g-2$ and will extend our study to lower pion masses and larger lattices in the future, including ensembles with $2+1$ flavours.

  7. Towards extracting the timelike pion form factor on CLS 2-flavour ensembles

    Science.gov (United States)

    Erben, F.; Green, J.; Mohler, D.; Wittig, H.

    Results are presented from an ongoing study of the $\\rho$ resonance. We use the distillation approach in order to create correlator matrices involving $\\rho$ and $\\pi\\pi$ interpolators. The study is done in a centre-of-mass frame and several moving frames. We are able to extract energy levels by solving the GEVP of those correlator matrices. The initial exploratory study is being done on a CLS 2-flavour lattice with a pion mass of $451$ $\\mathrm{MeV}$ using $\\mathcal{O}(a)$ improved Wilson fermions. One aim of this work is to extract the timelike pion form factor after applying the L\\"uscher formalism. We also plan to integrate this study with the existing Mainz programme for the calculation of the hadronic vacuum polarization contribution to the muon $g-2$ and will extend our study to lower pion masses and larger lattices in the future, including ensembles with $2+1$ flavours.

  8. Effects of ρ-meson width on pion distributions in heavy-ion collisions

    Science.gov (United States)

    Huovinen, Pasi; Lo, Pok Man; Marczenko, Michał; Morita, Kenji; Redlich, Krzysztof; Sasaki, Chihiro

    2017-06-01

    The influence of the finite width of ρ meson on the pion momentum distribution is studied quantitatively in the framework of the S-matrix approach combined with a blast-wave model to describe particle emissions from an expanding fireball. We find that the proper treatment of resonances which accounts for their production dynamics encoded in data for partial wave scattering amplitudes can substantially modify spectra of daughter particles originating in their two body decays. In particular, it results in an enhancement of the low-pT pions from the decays of ρ mesons which improves the quantitative description of the pion spectra in heavy ion collisions obtained by the ALICE collaboration at the LHC energy.

  9. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

    CERN Document Server

    Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bowles, J; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Golembiovskaya, M; Hadjidakis, C; Hartig, M; Hasch, D; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Ivanilov, A; Jackson, H E; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Ma, B -Q; Mahon, D; Makins, N C R; Manaenkov, S I; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Petrosyan, A; Raithel, M; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Seitz, B; Shibata, T -A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stinzing, F; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Wang, S; Yaschenko, S; Ye, Z; Yen, S; Yu, W; Zagrebelnyy, V; Zeiler, D; Zihlmann, B; Zupranski, P

    2013-01-01

    Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\\sin(\\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.

  10. Azimuthally Differential Pion Femtoscopy in Pb-Pb Collisions at √sNN = 2.76 TeV

    NARCIS (Netherlands)

    Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Janssen, M M; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Anson, C. D.; Antičić, T.; Antinori, F.; Antonioli, P.; Anwar, R.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.C.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barioglio, L.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.|info:eu-repo/dai/nl/411263188; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.|info:eu-repo/dai/nl/371577810; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.|info:eu-repo/dai/nl/371578248; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Blair, J. T.; Blau, D.; Blume, C.; Boca, G.; Bock, F.; Bogdanov, A.; Boldizsár, L.; Bombara, M.; Bonomi, G.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buhler, P.; Iga Buitron, S. A.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Caines, H.; Caliva, A.|info:eu-repo/dai/nl/411885812; Calvo Villar, E.; Camerini, P.; Capon, A. A.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A R; Ceballos Sanchez, C.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, Sukhee; Chochula, P.; Choi, K.; Chojnacki, M.|info:eu-repo/dai/nl/411888056; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Costanza, S.; Crkovská, J.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; Dasgupta, S. S.; De Caro, A.; De Cataldo, G.; De Conti, C.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. Derradi; Degenhardt, H. F.; Deisting, A.; Deloff, A.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, A.; Dobrin, A.|info:eu-repo/dai/nl/372618715; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.|info:eu-repo/dai/nl/355502488; Ducroux, L.; Duggal, A. K.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erhardt, F.; Espagnon, B.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A S; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; De Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Garg, P.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Gay Ducati, M. B.; Germain, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Graham, K. L.; Gramling, J. L.; Greiner, L. C.; Grelli, A.|info:eu-repo/dai/nl/326052577; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grion, N.; Gronefeld, J. M.; Grosa, F.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Grull, F. R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Hladky, J.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.W.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Ippolitov, M.; Irfan, M.; Isakov, V.; Islam, M. S.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H S Y; Jena, C.; Jena, S.; Jercic, M.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L.D.|info:eu-repo/dai/nl/370530780; Keil, M.; Ketzer, B.; Mohisin Khan, M.; Khan, P.M.; Khan, Shfaqat A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Khuntia, A.; Kielbowicz, M. M.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.-S.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.|info:eu-repo/dai/nl/371571227; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.L.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.|info:eu-repo/dai/nl/362845670; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.|info:eu-repo/dai/nl/074064975; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kundu, Seema; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.|info:eu-repo/dai/nl/355080192; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lavicka, R.; Lazaridis, L.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.|info:eu-repo/dai/nl/411295721; Strunz-Lehner, Christine; Lehrbach, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Litichevskyi, V.; Ljunggren, H. M.; Llope, W. J.; Lodato, D. F.; Loggins, V. R.; Loenne, P. I.; Loginov, V.; Loizides, C.; Loncar, P.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.|info:eu-repo/dai/nl/355080400; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.|info:eu-repo/dai/nl/412461684; Marín, Alicia; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martinez, J. A. L.; Martínez, Isabel M.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Mathis, A. M.; Matyja, A.; mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mihaylov, D. L.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.|info:eu-repo/dai/nl/325781435; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.|info:eu-repo/dai/nl/369405870; Mohanty, B.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Myers, C. J.; Naik, B.; Nair, Rajiv; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal Da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Nesbo, S. V.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.|info:eu-repo/dai/nl/07051349X; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Ohlson, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.|info:eu-repo/dai/nl/323375618; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pacik, V.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Panebianco, S.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, J.; Park, J.-W.; Parmar, S.; Passfeld, A.; Pathak, S. P.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.|info:eu-repo/dai/nl/304833959; Peng, X.; Pereira, L. G.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Pezzi, R. P.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L M; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Pozdniakov, V.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Rana, D. B.; Raniwala, R.; Raniwala, S.; Räsänen, S.; Rascanu, B. T.; Rathee, D.; Ratza, V.; Ravasenga, I.; Read, K. F.; Redlich, K.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.|info:eu-repo/dai/nl/413319628; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Rokita, P. S.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Rotondi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Rustamov, A.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Saha, S. K.; Sahlmuller, B.; Sahoo, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sandoval, A.; Sarkar, D.; Sarkar, N.; Sarma, P.; Sas, M. H.P.|info:eu-repo/dai/nl/413332993; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Scheid, H. S.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M. O.; Schmidt, M.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sett, P.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q. Y.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J.M.|info:eu-repo/dai/nl/165585781; Snellman, T. W.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A P; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Suzuki, K.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thakur, D.; Thakur, J. S.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; tripathy, S.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Trzeciak, B. A.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Umaka, E. N.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Van Der Maarel, J.|info:eu-repo/dai/nl/412860996; Van Hoorne, J. W.; Van Leeuwen, M.|info:eu-repo/dai/nl/250599171; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.|info:eu-repo/dai/nl/413533751; Velure, A.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Vértesi, R.; Vickovic, L.; Vigolo, S.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; Haller, B.; Vorobyev, I.; Voscek, D.; Vranic, D.; Vrláková, J.; Wagner, B.; Wagner, J.; Wang, H.|info:eu-repo/dai/nl/369509307; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C S; Windelband, B.; Witt, W. E.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I. K.; Yoon, J. H.; Yurchenko, V.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zimmermann, S.; Zinovjev, G.; Zmeskal, J.

    2017-01-01

    We present the first azimuthally differential measurements of the pion source size relative to the second harmonic event plane in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of √sNN = 2.76 TeV. The measurements have been performed in the centrality range 0%-50% and for pion

  11. Soft pions at high energy as an origin of flavor asymmetry of the light sea quarks in the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Koretune, Susumu [Dept. of Physics, Shimane Medical Univ., Izumo (Japan)

    2000-01-01

    By using the soft pion theorem in inclusive reactions, the soft pion contribution to the structure function F{sub 2} in the nucleon is estimated. It is shown that this contribution produces such a large flavor asymmetry in the light sea quark distributions that it gives about 30 - 50 % of the NMC deficit in the Gottfried sum. (author)

  12. Two-pion correlations in Au + Au collisions at 10.8 GeV/c per nucleon

    CERN Document Server

    Barrette, J; Bennett, S; Bersch, R; Braun-Munzinger, P; Chang, W C; Cleland, W E; Cole, J D; Cormier, T M; Dávid, G; Dee, J; Dietzsch, O; Drigert, M W; Gilbert, S J; Hall, J R; Hemmick, T K; Herrmann, N; Hong, B H; Jiang, C L; Johnson, S C; Kwon, Y; Lacasse, R; Lukaszew, A; Li, Q; Ludlam, Thomas W; McCorkle, S; Mark, S K; Mathéus, R D; Miskowiec, D; O'Brien, E; Panitkin, S; Piazza, T; Pollack, M E; Pruneau, C A; Rao, M N; Rosati, M; Da Silva, N C; Sedykh, S N; Sonnadara, U; Stachel, J J; Takagui, E M; Trzaska, M; Voloshin, S A; Vongpaseuth, T B; Wang, G; Wessels, J P; Woody, C L; Xu, N; Zhang, Y; Zou, C

    1997-01-01

    Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium.

  13. Two-pion correlations in Au+Au collisions at 10.8 GeV/c per nucleon

    OpenAIRE

    E877 Collaboration; Barrette, J.; Bellwied, R.; Bennett, S.; Bersch, R.; Braun-Munzinger, P.; Chang, W. C.; Cleland, W. E.; Cole, J. D.; Cormier, T. M.; David, G.; Dee, J.; Dietzsch, O.; Drigert, M. W.; Gilbert, S.

    1997-01-01

    Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium.

  14. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei.

  15. Nucleon-to-Pion Transition Distribution Amplitudes: A Challenge for P¯ANDA

    Science.gov (United States)

    Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.

    2014-06-01

    Baryon-to-meson transition distribution amplitudes (TDAs) appear as building blocks in the collinear factorized description of amplitudes for a class of hard exclusive reactions, prominent examples being hard exclusive pion electroproduction off a nucleon in the backward region and baryon-antibaryon annihilation into a pion and a lepton pair or a charmonium. Baryon-to-meson TDAs extend both the concepts of generalized parton distributions and baryon distribution amplitudes encoding valuable complementary information on the hadronic structure. We review the basic properties of baryon-to-meson TDAs and discuss the perspectives for the experimental access with the P¯ANDA detector.

  16. Unitarity corrections to a low-energy pion-nucleon scattering amplitude

    CERN Document Server

    Sá-Borges, J

    2000-01-01

    A method is present to unitarize a low energy pion-nucleon scattering amplitude. Starting from a soft-pion result, we have used unitarity directly as a dynamical constraint and constructed amplitudes from their first-order discontinuities. There is no commitment to the existence of resonances, but they can be derived from the general structure of the model. Working with two parameters we determine low energy pi N amplitudes. We have fixed the two parameters of the model by fitting the experimental P sub 3 sub 3 phase shifts near 90 deg. . Five S- and P-wave phase shifts are then shown to agree qualitatively with experimental data.

  17. Pion-Muon Concentrating System for Detectors of Highly Enriched Uranium

    CERN Document Server

    Kurennoy, Sergey; Blind, Barbara; Jason, Andrew J; Neri, Filippo

    2005-01-01

    One of many possible applications of low-energy antiprotons collected in a Penning trap can be a portable muon source. Released antiprotons annihilate on impact with normal matter producing on average about 3 charged pions per antiproton, which in turn decay into muons. Existence of such negative-muon sources of sufficient intensity would bring into play, for example, detectors of highly enriched uranium based on muonic X-rays. We explore options of collecting and focusing pions and resulting muons to enhance the muon flux toward the detector. Simulations with MARS and MAFIA are used to choose the target material and parameters of the magnetic system consisting of a few solenoids.

  18. Study of the interactions of pions in the CALICE silicon-tungsten calorimeter prototype

    CERN Document Server

    Adloff, C; Repond, J; Yu, J; Eigen, G; Mikami, Y; Watson, N K; Wilson, J A; Goto, T; Mavromanolakis, G; Thomson, M A; Ward, D R; Yan, W; Benchekroun, D; Hoummada, A; Khoulaki, Y; Apostolakis, J; Ribon, A; Uzhinskiy, V; Benyamna, M; Carloganu, C; Fehr, F; Gay, P; Blazey, G C; Chakraborty, D; Dyshkant, A; Francis, K; Hedin, D; Lima, J G; Zutshi, V; Hostachy, J Y; Krastev, K; Morin, L; D'Ascenzo, N; Cornett, U; David, D; Fabbri, R; Falley, G; Gadow, K; Garutti, E; Gottlicher, P; Jung, T; Karstensen, S; Lucaci-Timoce, A I; Lutz, B; Meyer, N; Morgunov, V; Reinecke, M; Sefkow, F; Smirnov, P; Vargas-Trevino, A; Wattimena, N; Wendt, O; Feege, N; Groll, M; Haller, J; Heuer, R D; Morozov, S; Richter, S; Samson, J; Kaplan, A; Schultz-Coulon, H C; Shen, W; Tadday, A; Bilki, B; Norbeck, E; Onel, Y; Kim, E J; Kim, G; Kim, D W; Lee, K; Lee, S C; Kawagoe, K; Tamura, Y; Dauncey, P D; Magnan, A M; Yilmaz, H; Zorba, O; Bartsch, V; Postranecky, M; Warren, M; Wing, M; Green, M G; Salvatore, F; Bedjidian, M; Kieffer, R; Laktineh, I; Fouz, M C; Bailey, D S; Barlow, R J; Kelly, M; Thompson, R J; Danilov, M; Tarkovsky, E; Baranova, N; Karmanov, D; Korolev, M; Merkin, M; Voronin, A; Frey, A; Lu, S; Seidel, K; Simon, F; Soldner, C; Weuste, L; Bonis, J; Bouquet, B; Callier, S; Cornebise, P; Doublet, Ph; Faucci Giannelli, M; Fleury, J; Li, H; Martin-Chassard, G; Richard, F; de la Taille, Ch; Poeschl, R; Raux, L; Seguin-Moreau, N; Wicek, F; Anduze, M; Boudry, V; Brient, J C; Gaycken, G; Jeans, D; Mora de Freitas, P; Musat, G; Reinhard, M; Rouge, A; Ruan, M; Vanel, J C; Videau, H; Park, K H; Zacek, J; Cvach, J; Gallus, P; Havranek, M; Janata, M; Marcisovsky, M; Polak, I; Popule, J; Tomasek, L; Tomasek, M; Ruzicka, P; Sicho, P; Smolik, J; Vrba, V; Zalesak, J; Belhorma, B; Belmir, M; Nam, S W; Park, I H; Yang, J; Chai, J S; Kim, J T; Kim, G B; Kang, J; Kwon, Y J

    2010-01-01

    A prototype silicon-tungsten electromagnetic calorimeter for an ILC detector was tested in 2007 at the CERN SPS test beam. Data were collected with electron and hadron beams in the energy range 8 to 80 GeV. The analysis described here focuses on the interactions of pions in the calorimeter. One of the main objectives of the CALICE program is to validate the Monte Carlo tools available for the design of a full-sized detector. The interactions of pions in the Si-W calorimeter are therefore confronted with the predictions of various physical models implemented in the GEANT4 simulation framework.

  19. Two-loop contribution to the pion transition form factor vs. experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, S.V.; Stefanis, N.G. [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation)

    2010-01-15

    We present predictions for the pion-photon transition form factor, which is derived with the help of light-cone sum rules and including the main part of the NNLO radiative corrections. We show that, when the Bakulev-Mikhailov-Stefanis (BMS) pion distribution amplitude is used, the obtained predictions agree well with the CELLO and the CLEO data. We found that no model distribution amplitude can reproduce the observed Q{sup 2} growth of the new BaBar data, though the BMS model complies with several BaBar data points.

  20. Two-loop contribution to the pion transition form factor vs. experimental data

    Science.gov (United States)

    Mikhailov, S. V.; Stefanis, N. G.

    2010-01-01

    We present predictions for the pion-photon transition form factor, which is derived with the help of light-cone sum rules and including the main part of the NNLO radiative corrections. We show that, when the Bakulev-Mikhailov-Stefanis (BMS) pion distribution amplitude is used, the obtained predictions agree well with the CELLO and the CLEO data. We found that no model distribution amplitude can reproduce the observed Q growth of the new BaBar data, though the BMS model complies with several BaBar data points.

  1. Systematic comparison of Tsallis statistics for charged pions produced in pp collisions

    Energy Technology Data Exchange (ETDEWEB)

    Parvan, A.S. [Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Horia Hulubei National Institute of Physics and Nuclear Engineering, Department of Theoretical Physics, Bucharest-Magurele (Romania); Teryaev, O.V. [Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Cleymans, J. [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Cape Town (South Africa)

    2017-05-15

    The energy dependence of Tsallis statistics parameters is presented for charged pions produced at beam energies ranging between 6.3 GeV and 7 TeV. It is found that deviations from Boltzmann statistics are monotonically growing with beam energy. The energy dependence of the parameters T and q of the negatively charged pions in the energy range 6.3 < √(s) < 7000 GeV reveals that the deviation of the transverse momentum distribution from the exponential becomes more and more pronounced as the beam energy is increased. The parameter q increases with beam energy while the temperature T slowly decreases. (orig.)

  2. Crossing symmetry and phenomenological widths in effective Lagrangian models of the pion photoproduction process

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Ramirez, C. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: cesar@nuc2.fis.ucm.es; Moya de Guerra, E. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)

    2008-02-21

    We investigate the importance of crossing symmetry in effective field models and the effects of phenomenological nucleon resonance widths on the paradigmatic case of pion photoproduction. We use reaction models containing four star resonances up to 1.8 GeV ({delta}(1232), N(1440), N(1520), N(1535), {delta}(1620), N(1650), {delta}(1700), and N(1720)) with different prescriptions for crossed terms and widths, to fit the latest world database on pion photoproduction. We compare {chi}{sup 2} results from selected multipoles and fits. The {chi}{sup 2} is highly dependent on the fulfillment of crossing symmetry and the inclusion of u channels.

  3. A facility for pion-induced nuclear reaction studies with HADES

    Energy Technology Data Exchange (ETDEWEB)

    Adamczewski-Musch, J.; Heinz, T.; Holzmann, R.; Koenig, I.; Koenig, W.; Kolb, B.W.; Pechenov, V.; Pietraszko, J.; Schmidt, C.J.; Schwab, E.; Sturm, C.; Traxler, M.; Wendisch, C.; Zumbruch, P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Arnold, O.; Berger-Chen, J.C.; Epple, E.; Fabbietti, L.; Lalik, R.; Lapidus, K.; Mihaylov, D.M.; Muenzer, R.; Wirth, J. [Excellence Cluster ' ' Origin and Structure of the Universe' ' , Garching (Germany); Technische Universitaet Muenchen, Physik Department E62, Garching (Germany); Behnke, C.; Blume, C.; Froehlich, I.; Kardan, B.; Lorenz, M.; Markert, J.; Michel, J.; Muentz, C.; Pechenova, O.; Scheib, T.; Schuldes, H.; Sellheim, P.; Stroebele, H.; Wiebusch, M.G. [Goethe-Universitaet, Institut fuer Kernphysik, Frankfurt (Germany); Belounnas, A.; Hennino, T.; Ramstein, B.; Rosier, P. [Institut de Physique Nucleaire, CNRS-IN2P3, Univ. Paris-Sud, Universite Paris-Saclay, Orsay (France); Belyaev, A.; Chernenko, S.; Fateev, O.; Ierusalimov, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Zanevsky, Y. [Joint Institute of Nuclear Research, Dubna (Russian Federation); Biernat, J.; Dybczak, A.; Korcyl, G.; Nowakowski, K.N.; Palka, M.; Przygoda, W.; Salabura, P.; Strzempek, P. [Jagiellonian University of Cracow, Smoluchowski Institute of Physics, Krakow (Poland); Blanco, A.; Bordalo, P.; Fonte, P.; Franco, C.; Lopes, L.; Mangiarotti, A.; Ramos, S.; Silva, L. [Fisica Experimental de Particulas, Laboratorio de Instrumentacao, Coimbra (Portugal); Boehmer, M.; Friese, J.; Gernhaeuser, R.; Kunz, T.; Maier, L.; Maurus, S.; Schmidt-Sommerfeld, K.; Siebenson, J. [Technische Universitaet Muenchen, Physik Department E62, Garching (Germany); Chlad, C.; Kugler, A.; Rodriguez-Ramos, P.; Sobolev, Yu.G.; Svoboda, O.; Tlusty, P.; Wagner, V. [Czech Academy of Sciences, Nuclear Physics Institute, Rez (Czech Republic); Deveaux, C.; Hoehne, C.; Mahmoud, T.; Metag, V. [Justus Liebig Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Dreyer, J.; Kaempfer, B.; Kotte, R.; Naumann, L. [Helmholtz-Zentrum Dresden-Rossendorf, Institut fuer Strahlenphysik, Dresden (Germany); Filip, P.; Hlavac, S. [Slovak Academy of Sciences, Institute of Physics, Bratislava (Slovakia); Galatyuk, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Technische Universitaet Darmstadt, Darmstadt (Germany); Garzon, J.A. [Univ. de Santiago de Compostela, LabCAF.F. Fisica, Santiago de Compostela (Spain); Golubeva, M.; Guber, F.; Ivashkin, A.; Karavicheva, T.; Kurepin, A.; Morozov, S.; Petukhov, O.; Reshetin, A.; Sadovsky, A.; Usenko, E. [Russian Academy of Science, Institute for Nuclear Research, Moscow (Russian Federation); Gumberidze, M.; Kornakov, G.; Rost, A.; Seck, F. [Technische Universitaet Darmstadt, Darmstadt (Germany); Harabasz, S. [Jagiellonian University of Cracow, Smoluchowski Institute of Physics, Krakow (Poland); Technische Universitaet Darmstadt, Darmstadt (Germany); Lebedev, A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Scordo, A. [INFN, Laboratori Nazionali di Frascati, Roma (Italy); Scozzi, F. [Technische Universitaet Darmstadt, Darmstadt (Germany); Institut de Physique Nucleaire, CNRS-IN2P3, Univ. Paris-Sud, Universite Paris-Saclay, Orsay (France); Spataro, S. [Dipartimento di Fisica, Universita di Torino (Italy); INFN, Torino (Italy); Stroth, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Goethe-Universitaet, Institut fuer Kernphysik, Frankfurt (Germany); Tsertos, H. [University of Cyprus, Department of Physics, Nicosia (Cyprus); Collaboration: HADES Collaboration

    2017-09-15

    The combination of a production target for secondary beams, an optimized ion optical beam line setting, in-beam detectors for minimum ionizing particles with high rate capability, and an efficient large acceptance spectrometer around the reaction target constitutes an experimental opportunity to study in detail hadronic interactions utilizing pion beams impinging on nucleons and nuclei. For the 0.4-2.0 GeV/c pion momentum regime such a facility is located at the heavy ion synchrotron accelerator SIS18 in Darmstadt (Germany). The layout of the apparatus, performance of its components and encouraging results from a first commissioning run are presented. (orig.)

  4. Pion, Kaon, Proton and Antiproton Production in Proton-Proton Collisions

    Science.gov (United States)

    Norbury, John W.; Blattnig, Steve R.

    2008-01-01

    Inclusive pion, kaon, proton, and antiproton production from proton-proton collisions is studied at a variety of proton energies. Various available parameterizations of Lorentz-invariant differential cross sections as a function of transverse momentum and rapidity are compared with experimental data. The Badhwar and Alper parameterizations are moderately satisfactory for charged pion production. The Badhwar parameterization provides the best fit for charged kaon production. For proton production, the Alper parameterization is best, and for antiproton production the Carey parameterization works best. However, no parameterization is able to fully account for all the data.

  5. New algorithms for identifying the flavour of [Formula: see text] mesons using pions and protons.

    Science.gov (United States)

    Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Aguiar Francisco, O; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Elsasser, Ch; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, P H; Hulsbergen, W; Humair, T; Hushchyn, M; Hussain, N; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kosmyntseva, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, B; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhu, X; Zhukov, V; Zucchelli, S

    2017-01-01

    Two new algorithms for use in the analysis of [Formula: see text] collision are developed to identify the flavour of [Formula: see text] mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using [Formula: see text] decays from [Formula: see text] collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a [Formula: see text] meson is the first of its kind.

  6. Ultracold neutral plasmas

    Science.gov (United States)

    Lyon, M.; Rolston, S. L.

    2017-01-01

    By photoionizing samples of laser-cooled atoms with laser light tuned just above the ionization limit, plasmas can be created with electron and ion temperatures below 10 K. These ultracold neutral plasmas have extended the temperature bounds of plasma physics by two orders of magnitude. Table-top experiments, using many of the tools from atomic physics, allow for the study of plasma phenomena in this new regime with independent control over the density and temperature of the plasma through the excitation process. Characteristic of these systems is an inhomogeneous density profile, inherited from the density distribution of the laser-cooled neutral atom sample. Most work has dealt with unconfined plasmas in vacuum, which expand outward at velocities of order 100 m/s, governed by electron pressure, and with lifetimes of order 100 μs, limited by stray electric fields. Using detection of charged particles and optical detection techniques, a wide variety of properties and phenomena have been observed, including expansion dynamics, collective excitations in both the electrons and ions, and collisional properties. Through three-body recombination collisions, the plasmas rapidly form Rydberg atoms, and clouds of cold Rydberg atoms have been observed to spontaneously avalanche ionize to form plasmas. Of particular interest is the possibility of the formation of strongly coupled plasmas, where Coulomb forces dominate thermal motion and correlations become important. The strongest impediment to strong coupling is disorder-induced heating, a process in which Coulomb energy from an initially disordered sample is converted into thermal energy. This restricts electrons to a weakly coupled regime and leaves the ions barely within the strongly coupled regime. This review will give an overview of the field of ultracold neutral plasmas, from its inception in 1999 to current work, including efforts to increase strong coupling and effects on plasma properties due to strong coupling.

  7. Ultracold neutral plasmas.

    Science.gov (United States)

    Lyon, M; Rolston, S L

    2017-01-01

    By photoionizing samples of laser-cooled atoms with laser light tuned just above the ionization limit, plasmas can be created with electron and ion temperatures below 10 K. These ultracold neutral plasmas have extended the temperature bounds of plasma physics by two orders of magnitude. Table-top experiments, using many of the tools from atomic physics, allow for the study of plasma phenomena in this new regime with independent control over the density and temperature of the plasma through the excitation process. Characteristic of these systems is an inhomogeneous density profile, inherited from the density distribution of the laser-cooled neutral atom sample. Most work has dealt with unconfined plasmas in vacuum, which expand outward at velocities of order 100 m/s, governed by electron pressure, and with lifetimes of order 100 μs, limited by stray electric fields. Using detection of charged particles and optical detection techniques, a wide variety of properties and phenomena have been observed, including expansion dynamics, collective excitations in both the electrons and ions, and collisional properties. Through three-body recombination collisions, the plasmas rapidly form Rydberg atoms, and clouds of cold Rydberg atoms have been observed to spontaneously avalanche ionize to form plasmas. Of particular interest is the possibility of the formation of strongly coupled plasmas, where Coulomb forces dominate thermal motion and correlations become important. The strongest impediment to strong coupling is disorder-induced heating, a process in which Coulomb energy from an initially disordered sample is converted into thermal energy. This restricts electrons to a weakly coupled regime and leaves the ions barely within the strongly coupled regime. This review will give an overview of the field of ultracold neutral plasmas, from its inception in 1999 to current work, including efforts to increase strong coupling and effects on plasma properties due to strong coupling.

  8. Lattice study of pion-pion scattering using Nf=2+1 Wilson improved quarks with masses down to their physical values

    CERN Document Server

    Metivet, Thibaut

    2014-01-01

    We use 2HEX smeared gauge configurations generated with an $\\mathrm{N}_\\mathrm{f}\\mathrm{=2+1}$ clover improved Wilson action to investigate $\\pi\\pi$ scattering in the $\\rho$ channel. The range of lattice spacings (0.054 to 0.12 fm) and space-like extents (32 and 48) allows us to extract the scattering parameters through the volume dependence of the $\\pi\\pi$-state energies according to L\\"uscher's formalism. The pion masses (134 to 300 MeV) are light enough to allow the decay of the rho and the level repulsion observed indicates that our data are sensitive to the interaction. We analyse our data with a multi-channel GEVP variational formula. Our results are in good agreement with the experimental values and consistent with a weak pion mass dependence of the $\\rho\\pi\\pi$ coupling constant.

  9. Improved measurement of neutral current coherent π0 production on carbon in a few-GeV neutrino beam

    Science.gov (United States)

    Kurimoto, Y.; Alcaraz-Aunion, J. L.; Brice, S. J.; Bugel, L.; Catala-Perez, J.; Cheng, G.; Conrad, J. M.; Djurcic, Z.; Dore, U.; Finley, D. A.; Franke, A. J.; Giganti, C.; Gomez-Cadenas, J. J.; Guzowski, P.; Hanson, A.; Hayato, Y.; Hiraide, K.; Jover-Manas, G.; Karagiorgi, G.; Katori, T.; Kobayashi, Y. K.; Kobilarcik, T.; Kubo, H.; Louis, W. C.; Loverre, P. F.; Ludovici, L.; Mahn, K. B. M.; Mariani, C.; Masuike, S.; Matsuoka, K.; McGary, V. T.; Metcalf, W.; Mills, G. B.; Mitsuka, G.; Miyachi, Y.; Mizugashira, S.; Moore, C. D.; Nakajima, Y.; Nakaya, T.; Napora, R.; Nienaber, P.; Orme, D.; Otani, M.; Russell, A. D.; Sanchez, F.; Shaevitz, M. H.; Shibata, T.-A.; Sorel, M.; Stefanski, R. J.; Takei, H.; Tanaka, H.-K.; Tanaka, M.; Tayloe, R.; Taylor, I. J.; Tesarek, R. J.; Uchida, Y.; van de Water, R.; Walding, J. J.; Wascko, M. O.; White, H. B.; Wilking, M. J.; Yokoyama, M.; Zeller, G. P.; Zimmerman, E. D.

    2010-06-01

    The SciBooNE Collaboration reports a measurement of neutral current coherent π0 production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive π0 production has been improved by detecting recoil protons from resonant π0 production. We measure the ratio of the neutral current coherent π0 production to total charged current cross sections to be (1.16±0.24)×10-2. The ratio of charged current coherent π+ to neutral current coherent π0 production is calculated to be 0.14-0.28+0.30, using our published charged current coherent pion measurement.

  10. Quantum statistics measurements using 2-, 3- and 4-pion Bose-Einstein correlations

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    We also present measurements of the source radii with 3-pion Bose-Einstein cumulants in pp, p-Pb, and Pb-Pb collisions. The resulting comparisons of the radii in all three systems at similar multiplicity has implications on the hydrodynamic modeling of high-energy collisions.

  11. Prospects for measuring coherent neutrino-nucleus elastic scattering at a stopped-pion neutrino source

    OpenAIRE

    Scholberg, Kate

    2005-01-01

    Rates of coherent neutrino-nucleus elastic scattering at a high-intensity stopped-pion neutrino source in various detector materials (relevant for novel low-threshold detectors) are calculated. Sensitivity of a coherent neutrino-nucleus elastic scattering experiment to new physics is also explored.

  12. On the effect of pion condensates on the spectrum of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Kolevatov, S. S.; Andrianov, A. A. [V. A. Fock Department of Theoretical Physics, Saint-Petersburg State University, 198504 St. Petersburg (Russian Federation); Espriu, D. [Departament d’Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)

    2016-01-22

    There is no precise theory describing the structure of neutron stars. However, inside such objects the baryon density is very high and a pion condensation may occur. These condensates, if they exist, might give a significant effect on a spectrum of neutron stars. We investigate this influence with a help of simplified model to give qualitative picture of the effect.

  13. New algorithms for identifying the flavour of B-0 mesons using pions and protons

    NARCIS (Netherlands)

    Dufour, L.; Mulder, M; Onderwater, C. J. G.; Pellegrino, A.; Tolk, S.; van Veghel, M.

    2017-01-01

    Two new algorithms for use in the analysis of pp collision are developed to identify the flavour of B mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using B-0 -> D- pi(+) decays from pp collision data collected by

  14. Beam-spin asymmetries in the azimuthal distribution of pion electroproduction

    NARCIS (Netherlands)

    Airapetian, A.; Blok, H.P.; Hesselink, W.H.A.; van der Nat, P.B.; Wang, S.

    2007-01-01

    A measurement of the beam-spin asymmetry in the azimuthal distribution of pions produced in semi-inclusive deep-inelastic scattering off protons is presented. The measurement was performed using the HERMES spectrometer with a hydrogen gas target and the longitudinally polarized 27.6 GeV positron

  15. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

    NARCIS (Netherlands)

    Airapetian, A.; Blok, H.P.

    2014-01-01

    Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the Hermes experiment. The asymmetries were studied as a function of the azimuthal angle ψ about the beam direction between the target-spin direction and the

  16. Precision Tracking and Electromagnetic Calorimetry Towards a Measurement of the Pion Polarisabilities at COMPASS

    CERN Document Server

    Dinkelbach, Anna-Maria Elisabeth

    2010-01-01

    In 2004 the COMPASS experiment at CERN SPS measured soft reactions with a beam of negatively charged pions on various nuclear targets. For this measurement, a silicon micro-strip telescope was installed in the target region. For the first time 5 silicon detector stations were operated simultaneously in the COMPASS experiment. A novel method of time calibration, with a clustering algorithm accordingly adapted, and refined alignment corrections were implemented in the analysis software. The spatial resolution of a silicon detector was determined to be 5 – 14 μm and the time resolution 2 – 3 ns. Combining the time information of all stations, a track time resolution of 530 ps from the silicon telescope could be reached. One of the key points of this experiment was the observation of Primakoff events, namely pions scattering off quasi-real photons in the Coulomb field of a heavy nucleus. The production of real photons corresponds to pion Compton scattering in inverse kinematics which is sensitive to the pion...

  17. Precursor of pion condensation: The softening of the quasi-elastic peak

    Science.gov (United States)

    Alberico, W. M.; Ericson, M.; Molinari, A.

    1980-05-01

    The phase transition of pion condensation is heralded in the disordered phase by an increase in the life time of the fluctuations for the staggered magnetization. This precursor phenomenon entails, in ordinary nuclei, a showing down of the nuclear quasi-elastic response when observed with spin-sensitive probes. Permanent address: Istituto di Fisica Teorica dell'Università di Torino, Turin, Italy.

  18. Precision measurement of the muon momentum in pion decay at rest

    Directory of Open Access Journals (Sweden)

    M. Daum

    1978-03-01

    Full Text Available A precision measurement of the μ+ momentum in π+ decay at rest has been made with a magnetic spectrometer. The result is pμ+ = (29.7873 ± 0.0014 MeV/c. The consequences of thisresult for the rest masses of the muon neutrino and of the positive pion are discussed.

  19. Energy Dependence of Pion and Kaon Production in Central Pb+Pb Collisions

    CERN Document Server

    Afanasiev, S.V.; Barna, D.; Bartke, J.; Barton, R.A.; Behler, M.; Betev, L.; Bialkowska, H.; Billmeier, A.; Blume, C.; Blyth, C.O.; Boimska, B.; Botje, M.; Bracinik, J.; Bramm, R.; Brun, R.; Buncic, P.; Cerny, V.; Cramer, J.G.; Csato, P.; Dinkelaker, P.; Eckardt, V.; Filip, P.; Fischer, H.G.; Fodor, Z.; Foka, P.; Freund, P.; Friese, V.; Gal, J.; Gazdzicki, M.; Georgopoulos, G.; Gladysz, E.; Hegyi, S.; Hohne, C.; Igo, G.; Jones, P.G.; Kadija, K.; Karev, A.; Kolesnikov, V.I.; Kollegger, T.; Kowalski, M.; Kraus, I.; Kreps, M.; van Leeuwen, M.; Levai, P.; Malakhov, A.I.; Margetis, S.; Markert, C.; Mayes, B.W.; Melkumov, G.L.; Mischke, A.; Molnar, J.; Nelson, John M.; Palla, G.; Panagiotou, A.D.; Perl, K.; Petridis, A.; Pikna, M.; Pinsky, Lawrence S.; Puhlhofer, F.; Reid, J.G.; Renfordt, R.; Retyk, W.; Roland, C.; Roland, G.; Rybicki, A.; Sammer, T.; Sandoval, A.; Sann, H.; Schmitz, N.; Seyboth, P.; Sikler, F.; Sitar, B.; Skrzypczak, E.; Squier, G.T.A.; Stock, R.; Strobele, H.; Susa, T.; Szentpetery, I.; Sziklai, J.; Trainor, T.A.; Varga, D.; Vassiliou, M.; Veres, G.I.; Vesztergombi, G.; Vranic, D.; Wenig, S.; Wetzler, A.; Whitten, C.; Yoo, I.K.; Zaranek, J.; Zimanyi, J.

    2002-01-01

    Results on the energy dependence of charged pion and kaon production in central Pb+Pb collisions at 40, 80 and 158 A GeV are presented and compared with data at lower and higher energies. The mean pion multiplicity increases approximately linearly with s^{1/4} with a change of slope around 40 A GeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies also occurs at about 40 A GeV. A non-monotonic energy dependence of the ratio of K+ to pi+ yields is observed, with a maximum close to 40 A GeV, followed by a nearly constant value at higher energies. The measured dependences are consistent with the hypothesis, derived within a Statistical Model of the Early Stage of nucleus-nucleus reactions, that a transient state of deconfined matter is created in Pb+Pb collisions for energies larger than about 40 A GeV.

  20. a Calculation of the Doubly Differential Cross Section for Inclusive Pion - HELIUM-4 Double Charge Exchange at Incident Pion Kinetic Energy Less than 270 Mev

    Science.gov (United States)

    Kulkarni, Arun Venkatesh

    Pi-nuclear scattering calculations that use multiple scattering usually require the knowledge not only of the pi-nucleon interaction in free space but also its modification inside a nuclear medium. A relativistic 3-Body model consisting of the pion, the i^ {rm th}-nucleon and the residual nucleus also called the core, is developed. In this model the nucleon core separation in co-ordinate space is approximated by the separation between the center of mass of the pi-i^{rm th} nucleon subsystem called the Composite, and the core. The instant form of dynamics was employed to introduce interactions between the pion and the nucleon and between the pi N Composite and the Core. The Composite-Core Hamiltonian is assumed to admit no bound states. The relativistic 3-Body total Hamiltonian is then diagonalized by nested-separable eigenfunctions. This diagonalization allows the construction of an expression for matrix elements of the medium modified pi N scattering operator tau_ {i} in the lab frame in terms of the CM pi N free space t-matrix elements. Terms that are quadratic in the pi N t -matrix elements in this expression are neglected. The Sequential Single Charge eXchange (SSCX) mechanism contribution to inclusive pi- ^4He Double Charge eXchange (DCX) is calculated using only the double scattering term of the Watson multiple scattering series. The tau-matrix elements obtained from the 3-Body model are used for the first scattering. It contains explicit dependance upon the matrix elements of the Composite-Core scattering operator t_{pi N-C}. This explicit dependance is ignored in the second scattering. The pole of the intermediate pion Green function is fixed from 3-Body model considerations and the requirement that pion be on the mass shell at the pole. The calculated inclusive cross sections {{d^2sigma}over{d Omega dT_pi}} are compared with the Kinney et al. experimental results and essential agreement with the spectrum for incident pion kinetic energy T_sp{pi}{rm In

  1. Quasifree photoproduction of eta-pion pairs off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Kaeser, Alexander [Departement of Physics, University of Basel, CH-4056 Basel, Switzerland (Switzerland); Collaboration: Crystal Ball/TAPS Collaboration

    2013-07-01

    The photoproduction of ηπ{sup 0} and ηπ{sup ±} pairs off the deuteron was investigated at the Mainz Microtron accelerator facility MAMI for photon energies up to 1.5 GeV. The detector setup consisted of the combined Crystal Ball and TAPS electromagnetic calorimeters. Invariant mass distributions for the neutral and charged channels as well as angular distributions for Φ and cos(Θ) were extracted from the data. In addition, total cross-sections for both channels have been extracted. The results are discussed in the context of the contributions of different resonances to the respective reactions.

  2. Electroweak single-pion production off the nucleon: From threshold to high invariant masses

    Science.gov (United States)

    González-Jiménez, R.; Jachowicz, N.; Niewczas, K.; Nys, J.; Pandey, V.; Van Cuyck, T.; Van Dessel, N.

    2017-06-01

    Neutrino-induced single-pion production (SPP) provides an important contribution to neutrino-nucleus interactions, ranging from intermediate to high energies. There exists a good number of low-energy models in the literature to describe the neutrino production of pions in the region around the Delta resonance. Those models consider only lowest-order interaction terms and, therefore, fail in the high-energy region (pion-nucleon invariant masses, W ≳2 GeV ). Our goal is to develop a model for electroweak SPP off the nucleon, which is applicable to the entire energy range of interest for present and future accelerator-based neutrino-oscillation experiments. We start with the low-energy model of [E. Hernández, J. Nieves, and M. Valverde, Phys. Rev. D 76, 033005 (2007)., 10.1103/PhysRevD.76.033005], which includes resonant contributions and background terms derived from the pion-nucleon Lagrangian of chiral-perturbation theory [S. Scherer and M. R. Schindler, A Primer for Chiral Perturbation Theory (Springer, Berlin, 2012), p. 1.]. Then, from the background contributions, we build a high-energy model using a Regge approach. The low- and high-energy models are combined, in a phenomenological way, into a hybrid model. The hybrid model is identical to the low-energy model in the low-W region, but, for W >2 GeV , it implements the desired high-energy behavior dictated by Regge theory. We have tested the high-energy model by comparing with one-pion production data from electron and neutrino reactions. The hybrid model is compared with electron-proton scattering data, with neutrino SPP data and with the predictions of the NuWro Monte Carlo event generator. Our model is able to provide satisfactory predictions of the electroweak one-pion production cross section from pion threshold to high W . Further investigation and more data are needed to better understand the mechanisms playing a role in the electroweak SPP process in the high-W region, in particular, those involving

  3. Multi-pion production in deuteron-proton collisions at COSY-ANKE

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Malte Marius

    2014-07-01

    The presented work is a contribution to the research on two- and three pion production in deuteron-proton collisions. Whereas the latter has received very little attention so far, the former is attracting the interest of particle physicists since several decades. An important reason for this is the appearance of the so-called ABC effect, a striking enhancement in the two-pion invariant mass spectrum near its threshold. There is strong evidence that this is related to the presence of nucleons and in the context of recent investigations it is even linked to an excitation of dibaryon resonances. The here presented results from an exclusive measurement of the dp→{sup 3}Heπ{sup +}π{sup -} reaction with the COSY-ANKE facility at an excess energy of 265 MeV benefit from high statistics as well as a good momentum resolution. Events with coincidentally detected {sup 3}Heπ{sup ±} and {sup 3}Heπ{sup +}π{sup -} combinations were used for the analysis. Various selection steps led to a very clean data sample. The limited geometrical acceptance of the ANKE detector was studied in detail in order to successfully elaborate a reliable correction method. Based on this, it was possible to determine differential and double differential cross sections for a large fraction of the backward {sup 3}He hemisphere. The derived invariant mass distributions do allow to illuminate further details of the two-pion production processes. Besides the prominent ABC enhancement, they reveal a significant difference in the behaviour of the positively and negatively charged pions, which is interpreted to be caused by π{sup +}π{sup -} isovector contributions. The total results are successfully described in terms of a N{sup *}(1440)→Δ(1232)→N decay chain. However, the isobar model surprisingly underestimates the charge difference at low two-pion invariant masses, indicating further contribution to the isovector channel. Investigations on the simultaneously measured dp→{sup 3}Heπ{sup +}

  4. Pion scattering to 8/sup -/ stretched states in /sup 60/Ni

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B.L.

    1988-03-01

    Using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility, differential cross sections for pion scattering were measured for ten previously known J/sup ..pi../ = 8/sup /minus// stretched states in /sup 60/Ni. A possible new pure isoscalar stretched state was also found. The data were taken near the /DELTA//sub 3,3/-resonance using 162 MeV incident pions and scattering angles of 65/degree/, 80/degree/, and 90/degree/ for ..pi../sup +/ and 65/degree/ and 80/degree/ for ..pi../sup /minus//. The analysis of the /sup 60/Ni data found that the use of Woods-Saxon wave functions in the theoretical calculations gave much better agreement with data than the use of the usual harmonic oscillator wave functions. The WS theory gave better predictions of: the angle at which the ..pi../sup /minus// and ..pi../sup +/ angular distributions are maximum, the ratios of ..pi../sup /minus// to ..pi../sup +/ cross sections for pure isovector states (which were much larger than unity), and the absolute size of the cross sections for all states (so that the normalization factor necessary to arrive at agreement of theory with data was closer to unity). The theoretical calculations used the distorted wave impulse approximation, including new methods for unbound states. The sensitivities of the calculations to input parameters were investigated. This analysis using WS wave functions was extended to five other nuclei (/sup 12/C, /sup 14/C, /sup 16/O, /sup 28/Si, and /sup 54/Fe) on which both pion scattering and electron scattering have been done. A significant improvement in arriving at a normalization factor close to unity was found when WS wave functions were consistently used for analyzing both pion and electron inelastic scattering data. 101 refs., 26 figs., 13 tabs.

  5. First Measurement of one Pion Production in Charged Current Neutrino and Antineutrino events on Argon

    Energy Technology Data Exchange (ETDEWEB)

    Scanavini, Scanavini,Giacomo [Yale U.

    2017-01-01

    This thesis presents a work done in the context of the Fermilab Neutrino Intensity Frontier. In this analysis, the cross section of single charged pion production in charged-current neutrino and antineutrino interactions with the argon nucleus target are measured. These measurements are performed using the Argon Neutrino Test (ArgoNeuT) detector exposed to the Fermilab Neutrino From The Main Injector (NuMI) beam operating in the low energy antineutrino mode. The signal is a charged-current μ interaction in the detector, with exactly one charged pion exiting the target nucleus, with momentum above 100 MeV/c. There shouldn’t be any 0 or kaons in the final state. There is no restriction on other mesons or nucleons. Total and differential cross section measurements are presented. The results are reported in terms of outgoing muon angle and momentum, outgoing pion angle and angle between outgoing pion and muon. The total cross sections, averaged over the flux, are found to be 8.2 ± 0.9 (stat) +0.9 -1.1 (syst) × 10-38 cm2 per argon nuclei and 2.5 ± 0.4 (stat) ± 0.5 (syst) × 10-37 cm2 per argon nuclei for antineutrino and neutrino respectively at a mean neutrino energy of 3.6 GeV (antineutrinos) and 9.6 GeV (neutrinos). This is the first time the single pion production in charged-current interactions cross section is measured on argon nuclei.

  6. In-medium modification of pion-pairs on deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Lugert, Stefan

    2007-11-23

    In this thesis the quasi free photo production of pion pairs on bound nucleons {gamma}+A{yields} {pi}{pi}(A-1)+N is analyzed for liquid Deuterium. A pioneering experiment with a photon beam was performed by the TAPS collaboration at the accelerator facility MAMI-B in Mainz in 1999. This measurement observed an invariant mass shift of the isoscalar {pi}{sup 0}{pi}{sup 0} channel with increasing atomic number as well. Due to the poor statistics, the significance of the data was however limited. The experiment described in this work reached a much higher statistical significance, allowing a review of the old data. In this experiment, the TAPS detector was used as a forward wall in combination with the Crystal Ball detector to achieve almost the complete 4{pi} solid angle coverage for particle detection at the MAMI accelerator facility. The installation of the experimental setup started at the end of 2003. The new readout electronics for the BaF{sub 2} crystals was used for the first time. Between June 2004 and April 2005 measurements on several targets were performed, including the lD{sub 2} data which has been analyzed in this work. The analysis of the Deuterium data is an essential contribution to understanding the ongoing processes for two reasons. Firstly, there is the possibility to compare the solid targets and Hydrogen to the lightest nucleus having Fermi motion included but the lowest possible nuclear volume, the Deuterium. For the second reason, there are no data for the mass differential cross section on the neutron available for the mentioned channels. Analyzing the Deuterium data and subtracting the published proton data, the cross section on the neutron gets accessible. An essential question for the theory is whether the cross section on neutron and proton are the same or how much they differ in the relevant energy regime. To determine the absolute cross section, the efficiency of the detector system is required. To provide this efficiency, I also

  7. Search for Charged Current Coherent Pion Production on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, K.; /Kyoto U.; Alcaraz-Aunion, J.L.; /Barcelona, IFAE; Brice, S.J.; /Fermilab; Bugel, Leonard G.; /MIT; Catala-Perez, J.; /Valencia U.; Cheng, G.; /Columbia U.; Conrad, J.M.; /MIT; Djurcic, Zelimir; /Columbia U.; Dore, U.; /Banca di Roma /Frascati; Finley, David A.; /Fermilab; Franke, A.J.; /Columbia U. /Banca di Roma /Frascati

    2008-11-01

    The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, nu{sub {mu}}{sup 12}C- {yields} {mu}{sup 12}Cpi{sup +}, with two distinct data samples. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at 0.67 x 10{sup -2} at mean neutrino energy 1.1 GeV and 1.36 x 10{sup -2} at mean neutrino energy 2.2 GeV.

  8. Search for charged current coherent pion production on carbon in a few-GeV neutrino beam

    Science.gov (United States)

    Hiraide, K.; Alcaraz-Aunion, J. L.; Brice, S. J.; Bugel, L.; Catala-Perez, J.; Cheng, G.; Conrad, J. M.; Djurcic, Z.; Dore, U.; Finley, D. A.; Franke, A. J.; Giganti, C.; Gomez-Cadenas, J. J.; Guzowski, P.; Hanson, A.; Hayato, Y.; Jover-Manas, G.; Karagiorgi, G.; Katori, T.; Kobayashi, Y. K.; Kobilarcik, T.; Kubo, H.; Kurimoto, Y.; Louis, W. C.; Loverre, P. F.; Ludovici, L.; Mahn, K. B. M.; Mariani, C.; Masuike, S.; Matsuoka, K.; Metcalf, W.; Mills, G.; Mitsuka, G.; Miyachi, Y.; Mizugashira, S.; Moore, C. D.; Nakajima, Y.; Nakaya, T.; Napora, R.; Nienaber, P.; Nguyen, V.; Orme, D.; Otani, M.; Russell, A. D.; Sanchez, F.; Shaevitz, M. H.; Shibata, T.-A.; Sorel, M.; Stefanski, R. J.; Takei, H.; Tanaka, H.-K.; Tanaka, M.; Tayloe, R.; Taylor, I. J.; Tesarek, R. J.; Uchida, Y.; van de Water, R.; Walding, J. J.; Wascko, M. O.; White, H.; Wilking, M. J.; Yokoyama, M.; Zeller, G. P.; Zimmerman, E. D.

    2008-12-01

    The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, νμC12→μ-C12π+, with two distinct data samples. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at 0.67×10-2 at mean neutrino energy 1.1 GeV and 1.36×10-2 at mean neutrino energy 2.2 GeV.

  9. Initial comparative response to peak pions and x-rays of normal skin and underlying tissue surrounding superficial metastatic nodules

    Energy Technology Data Exchange (ETDEWEB)

    Kligerman, M.M.; West, G.; Dicello, J.F.

    1976-01-01

    Given the limitations of available material and methods for measuring skin response, the relative biological effectiveness (RBE) for the development and healing of skin reaction to pions in this experiment is 1.43. This is based on data obtained from a patient with malignant melanoma, in whom multiple skin nodules and the surrounding normal skin were randomized into three dose levels for pions and x rays. The RBE for skin reaction was obtained while the skin tumor nodules appeared to regress at least as rapidly with pion therapy as with x rays. Without benefit of adequate observation of time required for nodule regrowth, any estimate of tumor RBE is speculative.

  10. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available The need for storage of renewable energy (RE generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel

  11. CO2-neutral fuels

    Science.gov (United States)

    Goede, A. P. H.

    2015-08-01

    The need for storage of renewable energy (RE) generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G) scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel cycle is

  12. Neutral evolution of mutational robustness.

    NARCIS (Netherlands)

    Nimwegen, E. van; Crutchfield, J.P.; Huynen, M.A.

    1999-01-01

    We introduce and analyze a general model of a population evolving over a network of selectively neutral genotypes. We show that the population's limit distribution on the neutral network is solely determined by the network topology and given by the principal eigenvector of the network's adjacency

  13. The merits of neutral theory

    NARCIS (Netherlands)

    Alonso, David; Etienne, Rampal S.; McKane, Alan J.

    Hubbell's neutral theory of biodiversity has challenged the classic niche-based view of ecological community structure. Although there have been many attempts to falsify Hubbell's theory, we argue that falsification should not lead to rejection, because there is more to the theory than neutrality

  14. The merits of neutral theory

    NARCIS (Netherlands)

    Alonso, D.; Etienne, R.S.; McKane, A.J.

    2006-01-01

    Hubbell's neutral theory of biodiversity has challenged the classic niche-based view of ecological community structure. Although there have been many attempts to falsify Hubbell's theory, we argue that falsification should not lead to rejection, because there is more to the theory than neutrality

  15. Net neutrality and audiovisual services

    NARCIS (Netherlands)

    van Eijk, N.; Nikoltchev, S.

    2011-01-01

    Net neutrality is high on the European agenda. New regulations for the communication sector provide a legal framework for net neutrality and need to be implemented on both a European and a national level. The key element is not just about blocking or slowing down traffic across communication

  16. Preequilibrium particle emissions and in-medium effects on the pion production in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhao-Qing [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China)

    2017-02-15

    Within the framework of the Lanzhou quantum molecular dynamics (LQMD) transport model, pion dynamics in heavy-ion collisions near threshold energies and the emission of preequilibrium particles (nucleons and light complex fragments) have been investigated. A density, momentum and isospin-dependent pion-nucleon potential based on the Δ-hole model is implemented in the transport approach, which slightly leads to the increase of the π{sup -}/π{sup +} ratio, but reduces the total pion yields. It is found that a bump structure of the π{sup -}/π{sup +} ratio in the kinetic energy spectra appears at the pion energy close to the Δ(1232) resonance region. The yield ratios of neutrons to protons from the squeeze-out particles perpendicular to the reaction plane are sensitive to the stiffness of nuclear symmetry energy, in particular at the high-momentum (kinetic energy) tails. (orig.)

  17. πN TDAs from charmonium production in association with a forward pion at P̅ANDA

    Science.gov (United States)

    Ma, B.; Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.

    2014-06-01

    Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs) at P̅ANDA. We briefly review the description of this reaction in terms of πN TDAs within the collinear factorization approach and present the first results of dedicated feasibility studies for the P̅ANDA experimental setup.

  18. πN TDAs from charmonium production in association with a forward pion at P̅ANDA

    Directory of Open Access Journals (Sweden)

    Ma B.

    2014-06-01

    Full Text Available Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs at P̅ANDA. We briefly review the description of this reaction in terms of πN TDAs within the collinear factorization approach and present the first results of dedicated feasibility studies for the P̅ANDA experimental setup.

  19. Subthreshold pion production: The effects of three body collisions the Fermi momentum, and the nuclear equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Molitoris, J.; Bonasera, A.; Adorno, A.

    1993-04-01

    The authors study pion production at subthreshold energies in nucleus-collisions using the extended Boltzmann-Nordheim-Vlasov (BNV) model. The extreme sensitivity of the pion yield to the initial momentum space Fermi distribution is demonstrated. The effect of the three body collision term is also shown to be substantial. However, the nuclear equation of state has no significant effect at these energies. Details and implications of the nuclear kinetic equation simulation are discussed.

  20. Neutral point detection by satellites. [magnetospheric neutral sheets

    Science.gov (United States)

    Schindler, K.; Ness, N. F.

    1974-01-01

    The concept of a neutral point depends on the physical phenomena described. The regions with B less than about 1 gamma detected by Schindler and Ness may be interpreted as neutral regions for the ion-tearing process. The assumption of the presence of a multiple neutral point structure (with temporal variations) is still the most promising interpretation of the Explorer 34 data. Alternatives suggested by Russell lead to difficulties. Nevertheless, the final answer can come only from multiple satellite systems. A 1-day displacement of the day count in the data discussed by Schindler and Ness is corrected.

  1. Measurement of the charged pion mass using a low-density target of light atoms

    CERN Document Server

    Trassinelli, M; Borchert, G; Dax, A; Egger, J -P; Gotta, D; Hennebach, M; Indelicato, P; Liu, Y -W; Manil, B; Nelms, N; Simons, L M; Wells, A

    2016-01-01

    We present a new evaluation of the negatively charged pion mass based on the simultaneous spec-troscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N 2 /O 2 mixture at 1.4 bar. We present the experimental setup and the methods for deriving the pion mass value from the spatial separation from the 5g -- 4 f $\\pi$N transition line and the 5g -- 4 f $\\mu$O transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  2. Two-pion-exchange in the non-mesonic weak decay of {lambda}-hypernuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chumillas, C. [Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, E-08028 Barcelona (Spain)], E-mail: chumi@ecm.ub.es; Garbarino, G. [Dipartimento di Fisica Teorica, Universita di Torino and INFN, Sezione di Torino, I-10125 Turin (Italy); Parreno, A.; Ramos, A. [Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, E-08028 Barcelona (Spain)

    2007-12-06

    The non-mesonic weak decay of {lambda}-hypernuclei is studied within a one-meson-exchange potential supplemented by a chirally motivated two-pion-exchange mechanism. The effects of final state interactions on the outgoing nucleons are also taken into account. Particular attention is payed to the asymmetry of the protons emitted by polarized hypernuclei. The one-meson-exchange model describes the non-mesonic rates and the neutron-to-proton ratio satisfactorily but predicts a too large and negative asymmetry parameter. The two-pion exchange mechanism modifies the strength and sign of some decay amplitudes. As a consequence, while the rates change moderately, the asymmetry parameter is strongly affected, acquiring values that lie well within the experimental observations.

  3. A Layer Correlation Technique for Pion Energy Calibration at the 2004 ATLAS Combined Beam Test

    CERN Document Server

    Grahn, Karl-Johan

    2009-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed. It is based on a principal component analysis of the calorimeter layer energy deposits, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the ATLAS calorimeters were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by about 20% compared to the electromagnetic scale.

  4. Measurement of the charged pion mass using a low-density target of light atoms

    Directory of Open Access Journals (Sweden)

    Trassinelli M.

    2016-01-01

    Full Text Available We present a new evaluation of the negatively charged pion mass based on the simultaneous spectroscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N2/O2 mixture at 1.4 bar. We present the experimental set-up and the methods for deriving the pion mass value from the spatial separation from the 5g − 4f πN transition line and the 5g − 4f μO transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  5. The First Pion-Ar Cross-Section Measurement with the LArIAT Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Nutini, Irene [GSSI, Aquila

    2016-01-01

    A complete understanding of neutrinos properties requires a study and a characterization of the interactions of the daughter particles created in a neutrino-nucleus interaction. The Liquid Argon In A Testbeam (LArIAT) experiment is a small-scale liquid argon detector situated in the Fermilab Test Beam Facility. The LArIAT experiment is exposed to a tertiary beam comprised of mostly pions along with a mix of muons, protons, kaons, and electrons. LArIAT's goal is to characterize the response of the LArTPC to known incoming charged particles and measure their interactions in Argon, in order to understand their cross-sections and to help developing and tuning simulations and reconstruction algorithms for LArTPC neutrino experiments. The world's rst measurement of a pion cross-section on an Argon target, made with the LArIAT detector, is presented here.

  6. Pion interferometry at RHIC: porobing a thermalized quark-gluon plasma?

    Science.gov (United States)

    Soff, S; Bass, S A; Dumitru, A

    2001-04-30

    We calculate the Gaussian radius parameters of the pion-emitting source in high-energy heavy-ion collisions, assuming a first-order phase transition from a thermalized quark-gluon plasma (QGP) to a gas of hadrons. Such a model leads to a very long-lived dissipative hadronic rescattering phase which dominates the properties of the two-pion correlation functions. The radii are found to depend only weakly on the thermalization time tau(i), the critical temperature Tc (and thus the latent heat), and the specific entropy of the QGP. The model calculations suggest a rapid increase of R(out)/R(side) as a function of KT if a thermalized QGP were formed.

  7. Sivers Asymmetries for Inclusive Pion and Kaon Production in Deep-Inelastic Scattering

    CERN Document Server

    Ellis, Jonathan Richard; Kotzinian, Aram

    2009-01-01

    We calculate the Sivers distribution functions induced by the final-state interaction due to one-gluon exchange in diquark models of nucleon structure, treating the cases of scalar and axial-vector diquarks with both dipole and Gaussian form factors. We use these distribution functions to calculate the Sivers single-spin asymmetries for inclusive pion and kaon production in deep-inelastic scattering. We compare our calculations with the results of HERMES and COMPASS, finding good agreement for pi+ production at HERMES, and qualitative agreement for pi0 and K+ production. Our predictions for pion and kaon production at COMPASS could be probed with increased statistics. The successful comparison of our calculations with the HERMES data constitutes prima facie evidence that the quarks in the nucleon have some orbital angular momentum in the infinite-momentum frame.

  8. Performance of the ATLAS Hadronic Endcap Calorimeter Modules to Electrons and Pions

    CERN Document Server

    Fortin, Dominique

    2000-01-01

    During the summer of 1999, the first six production modules of the Hadronic Endcap Calorimeter were assembled and installed in a beam test cryostat at CERN. In this thesis the performance of the calorimeter is assessed in terms of its response and resolution to electrons and pions The calorimeter is evaluated at five impact points and over an energy range of 10 to 200 GeV. The linearity of the response to electrons is observed to be within approximately one percent, and the average electromagnetic scale constant is measured to be 3.82 +/- 0.04 GeV/nA. The intrinsic energy resolution (not including the electronic noise) is obtained for electrons and pions. Comparison with Monte Carlo simulations and the effect of the electronics calibration procedure are discussed. Finally, the ratio of electromagnetic to hadronic response, e/h, is measured to be 1.509 +/- 0.021.

  9. Influence of the nuclear symmetry energy on the collective flows of charged pions

    Science.gov (United States)

    Gao, Yuan; Yong, Gao-Chan; Zhang, Lei; Zuo, Wei

    2018-01-01

    Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied charged pion transverse and elliptic flows in semicentral 197Au+197Au collisions at 600 MeV/nucleon. It is found that π+-π- differential transverse flow and the difference of π+ and π- transverse flows almost show no effects of the symmetry energy. Their corresponding elliptic flows are largely affected by the symmetry energy, especially at high transverse momenta. The isospin-dependent pion elliptic flow at high transverse momenta thus provides a promising way to probe the high-density behavior of the symmetry energy in heavy-ion collisions at the Facility for Antiproton and Ion Research (FAIR) at GSI, Darmstadt or at the Cooling Storage Ring (CSR) at HIRFL, Lanzhou.

  10. Two-Pion Production in Proton-Proton Collisions near Threshold

    Science.gov (United States)

    Hoistad, B.; Calen, H.; Fransson, K.; Gustafsson, L.; Haggstrom, S.; Hoistad, B.; Johansson, A.; Johanson, J.; Johansson, T.; Khoukaz, A.; Kullander, S.; Ruber, R.; Zlomanczuk, J.; Ekstrom, C.; Bilger, R.; Brodowski, W.; Clement, H.; Wagner, G. J.; Oelert, W.; Sefzick, T.; Greiff, J.; Koch, I.; Scobel, W.; Kupsc, A.; Marciniewski, P.; Stepaniak, J.; Morosov, B.; Povtorejko, A.; Sukhanov, A.; Zabierowski, J.; Shwartz, B.

    Two-pion production reactions in proton-proton collisions have been studied using the PROMICE/WASA detector and an internal cluster gas-jet target at the CELSIUS storage ring in Uppsala. The total cross sections for the pp → ppπ+π-, pp → ppπ0π0 and the pp → pnπ0π+ reactions are presented at beam energies ranging from 650 to 775 MeV. An isospin analysis of the amplitudes involved in these three reactions indicates that the excitation of the N*(1440) followed by direct two pion emission can be the most important amplitude when allowed. However, large contributions from other production mechanisms must also be prevalent to explain the large pp → pnπ0π+ cross section. The data are compared to an extensive model including non-resonant as well as resonant production via N* and Δ excitation.

  11. High resolution study of the inclusive production of massive muon pairs by intense pion beams

    CERN Multimedia

    2002-01-01

    This experiment measures with high resolution and large acceptance the inclusive production of massive muon pairs with the intense pion beam (up to $10^{10} \\pi/$pulse) in the experimental hall ECN3. The experiment explores extended M$^{2}$/s, x and transverse momentum ranges. The study of the departures of the lepton-pair production cross- section from scaling constitutes a good test of QCD ideas; in the framework of the 'Drell-Yan' process, the experiment allows a detailed study of the pion parton distribution functions. The detector consists of a beam dump, a pulsed toroidal a magnet, MWPC's and scintillator hodoscopes. Its $\\sim 2$% mass resolution at 10 GeV is adequate for the substraction of resonances in the high-mass region.

  12. On the Role of One Pion Exchange and Heavy Quark Spin Symmetry in Heavy Meson Molecules

    Directory of Open Access Journals (Sweden)

    Pavón Valderrama M.

    2012-12-01

    Full Text Available In this contribution we consider the theoretical description of heavy mesonantimeson molecules from the effective field theory perspective. We are interested in the role of one pion exchange and heavy quark spin symmetry in the low energy description of the molecular states. We find that pion exchanges are weaker than naively expected. As a consequence, at lowest order in the effective expansion, the heavy meson-antimeson dynamics are driven by contact range interactions that are in turn heavily constrained by heavy quark spin symmetry. We find that if the X(3872 DD¯*${m{Dar D*}}$ is a bound state with quantum numbers JPC = 1++, we should expect the existence of a 2++ DD¯*${m{Dar D*}}$ molecule with a mass of 4012 MeV. If we also assume the X(3915 resonance to be molecular, we end up deriving the location of three new states with masses of 3710, 3820 and 3855 MeV.

  13. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Science.gov (United States)

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T. P. A.; Aleksa, M.; Alexa, C.; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Atkinson, T.; Baines, J.; Baker, O. K.; Banfi, D.; Baron, S.; Barr, A. J.; Beccherle, R.; Beck, H. P.; Belhorma, B.; Bell, P. J.; Benchekroun, D.; Benjamin, D. P.; Benslama, K.; Bergeaas Kuutmann, E.; Bernabeu, J.; Bertelsen, H.; Binet, S.; Biscarat, C.; Boldea, V.; Bondarenko, V. G.; Boonekamp, M.; Bosman, M.; Bourdarios, C.; Broklova, Z.; Burckhart Chromek, D.; Bychkov, V.; Callahan, J.; Calvet, D.; Canneri, M.; Capeáns Garrido, M.; Caprini, M.; Cardiel Sas, L.; Carli, T.; Carminati, L.; Carvalho, J.; Cascella, M.; Castillo, M. V.; Catinaccio, A.; Cauz, D.; Cavalli, D.; Cavalli Sforza, M.; Cavasinni, V.; Cetin, S. A.; Chen, H.; Cherkaoui, R.; Chevalier, L.; Chevallier, F.; Chouridou, S.; Ciobotaru, M.; Citterio, M.; Clark, A.; Cleland, B.; Cobal, M.; Cogneras, E.; Conde Muino, P.; Consonni, M.; Constantinescu, S.; Cornelissen, T.; Correard, S.; Corso Radu, A.; Costa, G.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Cwetanski, P.; Da Silva, D.; Dam, M.; Dameri, M.; Danielsson, H. O.; Dannheim, D.; Darbo, G.; Davidek, T.; De, K.; Defay, P. O.; Dekhissi, B.; Del Peso, J.; Del Prete, T.; Delmastro, M.; Derue, F.; Di Ciaccio, L.; Di Girolamo, B.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Dobos, D.; Dobson, M.; Dolgoshein, B. A.; Dotti, A.; Drake, G.; Drasal, Z.; Dressnandt, N.; Driouchi, C.; Drohan, J.; Ebenstein, W. L.; Eerola, P.; Efthymiopoulos, I.; Egorov, K.; Eifert, T. F.; Einsweiler, K.; El Kacimi, M.; Elsing, M.; Emelyanov, D.; Escobar, C.; Etienvre, A. I.; Fabich, A.; Facius, K.; Fakhr-Edine, A. I.; Fanti, M.; Farbin, A.; Farthouat, P.; Fassouliotis, D.; Fayard, L.; Febbraro, R.; Fedin, O. L.; Fenyuk, A.; Fergusson, D.; Ferrari, P.; Ferrari, R.; Ferreira, B. C.; Ferrer, A.; Ferrere, D.; Filippini, G.; Flick, T.; Fournier, D.; Francavilla, P.; Francis, D.; Froeschl, R.; Froidevaux, D.; Fullana, E.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, M.; Gallop, B. J.; Gameiro, S.; Gan, K. K.; Garcia, R.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Ghodbane, N.; Giakoumopoulou, V.; Giangiobbe, V.; Giokaris, N.; Glonti, G.; Goettfert, T.; Golling, T.; Gollub, N.; Gomes, A.; Gomez, M. D.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Gorini, B.; Goujdami, D.; Grahn, K.-J.; Grenier, P.; Grigalashvili, N.; Grishkevich, Y.; Grosse-Knetter, J.; Gruwe, M.; Guicheney, C.; Gupta, A.; Haeberli, C.; Haertel, R.; Hajduk, Z.; Hakobyan, H.; Hance, M.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Harvey, A., Jr.; Hawkings, R. J.; Heinemann, F. E. W.; Henriques Correia, A.; Henss, T.; Hervas, L.; Higon, E.; Hill, J. C.; Hoffman, J.; Hostachy, J. Y.; Hruska, I.; Hubaut, F.; Huegging, F.; Hulsbergen, W.; Hurwitz, M.; Iconomidou-Fayard, L.; Jansen, E.; Jen-La Plante, I.; Johansson, P. D. C.; Jon-And, K.; Joos, M.; Jorgensen, S.; Joseph, J.; Kaczmarska, A.; Kado, M.; Karyukhin, A.; Kataoka, M.; Kayumov, F.; Kazarov, A.; Keener, P. T.; Kekelidze, G. D.; Kerschen, N.; Kersten, S.; Khomich, A.; Khoriauli, G.; Khramov, E.; Khristachev, A.; Khubua, J.; Kittelmann, T. H.; Klingenberg, R.; Klinkby, E. B.; Kodys, P.; Koffas, T.; Kolos, S.; Konovalov, S. P.; Konstantinidis, N.; Kopikov, S.; Korolkov, I.; Kostyukhin, V.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; Kulchitsky, Y.; Lacasta, C.; Lafaye, R.; Laforge, B.; Lampl, W.; Lanni, F.; Laplace, S.; Lari, T.; Le Bihan, A.-C.; Lechowski, M.; Ledroit-Guillon, F.; Lehmann, G.; Leitner, R.; Lelas, D.; Lester, C. G.; Liang, Z.; Lichard, P.; Liebig, W.; Lipniacka, A.; Lokajicek, M.; Louchard, L.; Lourerio, K. F.; Lucotte, A.; Luehring, F.; Lund-Jensen, B.; Lundberg, B.; Ma, H.; Mackeprang, R.; Maio, A.; Maleev, V. P.; Malek, F.; Mandelli, L.; Maneira, J.; Mangin-Brinet, M.; Manousakis, A.; Mapelli, L.; Marques, C.; Garcia, S. Marti i.; Martin, F.; Mathes, M.; Mazzanti, M.; McFarlane, K. W.; McPherson, R.; Mchedlidze, G.; Mehlhase, S.; Meirosu, C.; Meng, Z.; Meroni, C.; Mialkovski, V.; Mikulec, B.; Milstead, D.; Minashvili, I.; Mindur, B.; Mitsou, V. A.; Moed, S.; Monnier, E.; Moorhead, G.; Morettini, P.; Morozov, S. V.; Mosidze, M.; Mouraviev, S. V.; Moyse, E. W. J.; Munar, A.; Myagkov, A.; Nadtochi, A. V.; Nakamura, K.; Nechaeva, P.; Negri, A.; Nemecek, S.; Nessi, M.; Nesterov, S. Y.; Newcomer, F. M.; Nikitine, I.; Nikolaev, K.; Nikolic-Audit, I.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Onofre, A.; Padilla Aranda, C.; Paganis, S.; Pallin, D.; Pantea, D.; Paolone, V.; Parodi, F.; Parsons, J.; Parzhitskiy, S.; Pasqualucci, E.; Passmored, S. M.; Pater, J.; Patrichev, S.; Peez, M.; Perez Reale, V.; Perini, L.; Peshekhonov, V. D.; Petersen, J.; Petersen, T. C.; Petti, R.; Phillips, P. W.; Pina, J.; Pinto, B.; Podlyski, F.; Poggioli, L.; Poppleton, A.; Poveda, J.; Pralavorio, P.; Pribyl, L.; Price, M. J.; Prieur, D.; Puigdengoles, C.; Puzo, P.; RØhne, O.; Ragusa, F.; Rajagopalan, S.; Reeves, K.; Reisinger, I.; Rembser, C.; Bruckman de Renstrom, P. A.; Reznicek, P.; Ridel, M.; Risso, P.; Riu, I.; Robinson, D.; Roda, C.; Roe, S.; Rohne, O.; Romaniouk, A.; Rousseau, D.; Rozanov, A.; Ruiz, A.; Rusakovich, N.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Salto, O.; Salvachua, B.; Salzburger, A.; Sandaker, H.; Santamarina Rios, C.; Santi, L.; Santoni, C.; Saraiva, J. G.; Sarri, F.; Sauvage, G.; Says, L. P.; Schaefer, M.; Schegelsky, V. A.; Schiavi, C.; Schieck, J.; Schlager, G.; Schlereth, J.; Schmitt, C.; Schultes, J.; Schwemling, P.; Schwindling, J.; Seixas, J. M.; Seliverstov, D. M.; Serin, L.; Sfyrla, A.; Shalanda, N.; Shaw, C.; Shin, T.; Shmeleva, A.; Silva, J.; Simion, S.; Simonyan, M.; Sloper, J. E.; Smirnov, S. Yu; Smirnova, L.; Solans, C.; Solodkov, A.; Solovianov, O.; Soloviev, I.; Sosnovtsev, V. V.; Spanò, F.; Speckmayer, P.; Stancu, S.; Stanek, R.; Starchenko, E.; Straessner, A.; Suchkov, S. I.; Suk, M.; Szczygiel, R.; Tarrade, F.; Tartarelli, F.; Tas, P.; Tayalati, Y.; Tegenfeldt, F.; Teuscher, R.; Thioye, M.; Tikhomirov, V. O.; Timmermans, C. J. W. P.; Tisserant, S.; Toczek, B.; Tremblet, L.; Troncon, C.; Tsiareshka, P.; Tyndel, M.; Karagoez Unel, M.; Unal, G.; Unel, G.; Usai, G.; Van Berg, R.; Valero, A.; Valkar, S.; Valls, J. A.; Vandelli, W.; Vannucci, F.; Vartapetian, A.; Vassilakopoulos, V. I.; Vasilyeva, L.; Vazeille, F.; Vernocchi, F.; Vetter-Cole, Y.; Vichou, I.; Vinogradov, V.; Virzi, J.; Vivarelli, I.; de Vivie, J. B.; Volpi, M.; Anh, T. Vu; Wang, C.; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Werner, P.; Wheeler, S.; Wiessmann, M.; Wilkens, H.; Williams, H. H.; Wingerter-Seez, I.; Yasu, Y.; Zaitsev, A.; Zenin, A.; Zenis, T.; Zenonos, Z.; Zhang, H.; Zhelezko, A.; Zhou, N.

    2011-06-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  14. Three pion correlations in sulphur-lead collisions at the CERN SPS

    CERN Document Server

    Bøggild, H; Dodd, J; Esumi, S C; Fabjan, Christian Wolfgang; Ferenc, D; Franz, A; Hardtke, D; van Hecke, H; Humanic, T J; Ikemoto, T; Jacak, B V; Kalechofsky, H; Kobayashi, T; Kvatadze, R A; Lee, Y Y; Leltchouk, M; Lörstad, B; Maeda, N; Miake, Y; Miyabayashi, A; Murray, M; Nagamiya, S; Nishimura, S; Paic, G; Pandey, S U; Piuz, François; Polychronakos, V; Potekhin, M V; Poulard, G; Rahm, David Charles; Rieubland, Jean Michel; Sakaguchi, A; Sarabura, M; Shigaki, K; Simon-Gillo, J; Schmidt-Sørensen, J; Sondheim, W E; Sugitate, T; Sullivan, J P; Sumi, Y; Willis, W J

    1999-01-01

    $\\pi^+\\pi^+\\pi^+$ correlations from Sulphur-Lead collisions at 200 GeV/c per nucleon are presented as measured by the focusing spectrometer of experiment NA44 at CERN. We have investigated the three-pion correlation function at mid-rapidity and found that a genuine three-body correlation is suppressed. A possible interpretation of this result is that the emission of particles is partially coherent.

  15. Test of the ATLAS pion calibration scheme in the ATLAS combined test beam

    CERN Document Server

    Spanò, F

    2009-01-01

    Pion energy reconstruction is studied using the data collected during the 2004 ATLAS combined test beam. The strategy to extract corrections for the non-compensating nature of the ATLAS calorimeters for dead material losses and for leakage effects is discussed and assessed. The default ATLAS strategy based on a weighting technique of the energy deposits in calorimeter cells is presented and compared to a novel technique exploiting correlations among energy deposited in calorimeter layers.

  16. LArIAT: Worlds First Pion-Argon Cross-Section

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Pip [Fermilab

    2016-11-02

    The LArIAT experiment has performed the world's first measurement of the total charged-current pion cross-section on an argon target, using the repurposed ArgoNeuT detector in the Fermilab test beam. Presented here are the results of that measurement, along with an overview of the LArIAT experiment and details of the LArIAT collaboration's plans for future measurements.

  17. Rare Kaon and Pion Decays: Incisive Probes for New Physics Beyond the Standard Model

    Science.gov (United States)

    Bryman, Douglas; Marciano, William J.; Tschirhart, Robert; Yamanaka, Taku

    2011-11-01

    We review the current status and future prospects of rare kaon and pion decay research programs. Our emphasis is on experimental probes of New Physics beyond the Standard Model via the theoretically pristine [Formula: see text] decays and precision tests of electron-muon universality. These studies test the Standard Model at the level of its quantum-loop predictions and have the potential to uncover new interactions beyond the O(1,000 TeV) scale.

  18. Exchange-current contribution to the pion-deuteron scattering length

    Science.gov (United States)

    Robilotta, M. R.

    1980-05-01

    Chiral symmetry, implemented by means of effective lagrangians, is used to evaluate the exchange-current contribution to the pion-deuteron scattering length. It is shown that this approximate ssymmetry is responsible for partial cancellations, yielding an overall contribution of about 10% of the total scattering length. Work supported in part by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico, Brazil.

  19. Measurement of the muon-neutrino charged-current cross section on water with zero pions

    CERN Document Server

    Yuan, Tianlu

    2016-01-01

    The Tokai to Kamioka (T2K) experiment is a 295-km long-baseline neutrino experiment aimed towards the measurement of neutrino oscillation parameters ${\\theta}_{13}$ and ${\\theta}_{23}$. Precise measurement of these parameters requires accurate knowledge of neutrino cross sections. We present a flux-averaged double differential measurement of the charged-current cross section on water with zero pions in the final state using the T2K off-axis near detector, ND280. A selection of $\

  20. Pion elastic and inelastic scattering from 51V at 180 MeV

    Science.gov (United States)

    Oakley, D. S.; Machuca, M. A.; Smithson, M. J.; Mordechai, S.; Moore, C. Fred; Seidl, P. A.; Morris, C. L.; Wang, Z. F.; Gilman, R.; Zumbro, J. D.; Fortune, H. T.; Seestrom-Morris, S. J.; Dhuga, K. S.; Watson, D. L.

    1987-09-01

    Differential cross sections were measured for pion elastic and inelastic scattering from 51V at Tπ=180 MeV. Elastic scattering data were analyzed using a standard Kisslinger potential. Inelastic scattering data were analyzed using distorted-wave impulse-approximation calculations with collective-model transition densities. Ground-state neutron-density parameters and matrix elements for some of the transitions were extracted.

  1. Pion-interferometry analysis in relativistic heavy-ion collisions based on the VENUS model

    Energy Technology Data Exchange (ETDEWEB)

    Chao, W.Q. (China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing 100080 (China) Institute of High Energy Physics, Academia Sinica, P.O. Box 918 (4), Beijing 100039 (China) Institute of Theoretical Physics, Academia Sinica, P.O. Box 2735, Beijing 100080 (China)); Gao, C.S. (China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing 100080 (China) Institute of Theoretical Physics, Academia Sinica, P.O. Box 2735, Beijing 100080 (China) Physics Department, Peking University, Beijing 100871 (China)); Zhang, Q.H. (China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing 100080 (China) Physics Department, Peking University, Beijing 100871 (China))

    1994-06-27

    The source size in relativistic heavy-ion collisions obtained by pion-interferometry analyses based on the VENUS model is compared with the actual source size of the model and experimental measurements. The predicted transverse source size is larger than the size of the projectile nuclei, but smaller than the preliminary findings from a recent experiment in the central rapidity region. The effect of rescattering on the source size is also discussed. ((orig.))

  2. Pion and proton showers in the CALICE scintillator-steel analogue hadron calorimeter

    CERN Document Server

    Bilki, B.; Xia, L.; Eigen, G.; Thomson, M.A.; Ward, D.R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Chang, S.; Khan, A.; Kim, D.H.; Kong, D.J.; Oh, Y.D.; Blazey, G.C.; Dyshkant, A.; Francis, K.; Lima, J.G.R.; Salcido, R.; Zutshi, V.; Salvatore, F.; Kawagoe, K.; Miyazaki, Y.; Sudo, Y.; Suehara, T.; Tomita, T.; Ueno, H.; Yoshioka, T.; Apostolakis, J.; Dannheim, D.; Folger, G.; Ivantchenko, V.; Klempt, W.; Lucaci-Timoce, A. -I.; Ribon, A.; Schlatter, D.; Sicking, E.; Uzhinskiy, V.; Giraud, J.; Grondin, D.; Hostachy, J. -Y.; Morin, L.; Brianne, E.; Cornett, U.; David, D.; Ebrahimi, A.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krüger, K.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Neubüser, C.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Tran, H.L.; Buhmann, P.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Munwes, Y.; Schultz-Coulon, H. -Ch.; Shen, W.; Stamen, R.; Norbeck, E.; Northacker, D.; van Doren, B.; Wilson, G.W.; Wing, M.; Combaret, C.; Caponetto, L.; Eté, R.; Grenier, G.; Han, R.; Ianigro, J.C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Antequera, J. Berenguer; Calvo Alamillo, E.; Fouz, M. -C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Corriveau, F.; Bobchenko, B.; Chistov, R.; Chadeeva, M.; Danilov, M.; Drutskoy, A.; Epifantsev, A.; Markin, O.; Mironov, D.; Mizuk, R.; Novikov, E.; Rusinov, V.; Tarkovsky, E.; Besson, D.; Buzhan, P.; Ilyin, A.; Popova, E.; Gabriel, M.; Kiesling, C.; van der Kolk, N.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M.S.; Bonis, J.; Conforti Di Lorenzo, S.; Cornebise, P.; Dulucq, F.; Fleury, J.; Frisson, T.; Martin-Chassard, G.; Poschl, R.; Raux, L.; Richard, F.; Pöschl, R.; Rouëné, J.; Seguin-Moreau, N.; de la Taille, Ch.; Anduze, M.; Boudry, V.; Brient, J-C.; Clerc, C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Matthieu, A.; Mora de Freitas, P.; Musat, G.; Ruan, M.; Videau, H.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Jeans, D.; Weber, S.

    2015-01-01

    Showers produced by positive hadrons in the highly granular CALICE scintillatorsteel analogue hadronic calorimeter were studied. The experimental data were collected at CERN and FNAL for single particles with initial momenta from 10 to 80 GeV/c. The calorimeter response and resolution and spatial characteristics of shower development for proton- and pion-induced showers for test beam data and simulations using GEANT4 version 9.6 are compared.

  3. An analytic analysis of the pion decay constant in three-flavoured chiral perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Ananthanarayan, B.; Ghosh, Shayan [Indian Institute of Science, Centre for High Energy Physics, Bangalore, Karnataka (India); Bijnens, Johan [Lund University, Department of Astronomy and Theoretical Physics, Lund (Sweden)

    2017-07-15

    A representation of the two-loop contribution to the pion decay constant in SU(3) chiral perturbation theory is presented. The result is analytic up to the contribution of the three (different) mass sunset integrals, for which an expansion in their external momentum has been taken. We also give an analytic expression for the two-loop contribution to the pion mass based on a renormalized representation and in terms of the physical eta mass. We find an expansion of F{sub π} and M{sub π}{sup 2} in the strange-quark mass in the isospin limit, and we perform the matching of the chiral SU(2) and SU(3) low-energy constants. A numerical analysis demonstrates the high accuracy of our representation, and the strong dependence of the pion decay constant upon the values of the low-energy constants, especially in the chiral limit. Finally, we present a simplified representation that is particularly suitable for fitting with available lattice data. (orig.)

  4. Pion correlations as a function of atomic mass in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Chacon, A.D.

    1989-11-26

    The method of two pion interferometry was used to obtain source-size and lifetime parameters for the pions produced in heavy ion collisions. The systems used were 1.70 {center dot} A GeV {sup 56}Fe + Fe, 1.82 {center dot} A GeV {sup 40}Ar + KCl and 1.54 {center dot} A GeV {sup 93}Nb + Nb, allowing for a search for dependences on the atomic number. Two acceptances (centered, in the lab., at {approximately} 0{degrees} and 45{degrees}) were used for each system, allowing a search for dependences on the viewing angle. The correlation functions were calculated by comparing the data samples to background (or reference) samples made using the method of event mixing, where pions from different events are combined to produce a data sample in which the Bose-Einstein correlation effect is absent. The effect of the correlation function on the background samples is calculated, and a method for weighting the events to remove the residual correlation effect is presented. The effect of the spectrometer design on the measured correlation functions is discussed, as are methods for correcting for these effects during the data analysis. 58 refs., 39 figs., 18 tabs.

  5. Pion Radiation Damage in InGaAs p-i-n Photodiodes

    CERN Document Server

    Gill, Karl; Cervelli, Giovanni; Grabit, Robert; Mommaert, Chantal; Stefanini, Giorgio; Troska, Jan; Vasey, François

    1998-01-01

    Fully packaged InGaAs p-i-n photodiodes for use in CMS Tracker optical digital timing and control links have been irradiated at room temperature with 330MeV positive pions. Measurements of the leakage current and photocurrent response were made in-situ for pion fluences up to 3.9x10 14pi+/cm2. The leakage current increases from <1nA to 40 muA at 5V reverse bias and the photocurrent for 100 muW incident optical power decreases from 90 muW to 18 muW after 2x10 14 pi+/cm2. 330MeV pions cause a similar level of damage to 24GeV protons and several times more damage than 6MeV neutrons. The leakage current damage anneals slowly and no significant recovery of the photocurrent damage occurs at temperatures up to 80 degree C. Although the damage effects are relatively large they are tolerable in the CMS tracker digital timing/control optical link system.

  6. Study of the pion trajectory in the photoproduction of leading neutrons at HERA

    CERN Document Server

    Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; D'Agostini, Giulio; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fricke, U; Fusayasu, T; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Gliga, S; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Grigorescu, G; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, M; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lainesse, J; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Notz, D; Nowak, R J; Nuncio, A E; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Palmonari, F; Parenti, A; Park, I H; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Rinaldi, L; Riveline, U; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J

    2004-01-01

    Energetic neutrons produced in ep collisions at HERA have been studied with the ZEUS detector in the photoproduction regime at a mean photon-proton center-of-mass energy of 220 GeV. The neutrons carry a large fraction 0.6 < x_L < 0.925 of the incoming proton energy and the four-momentum-transfer squared at the proton-neutron vertex is small, |t| < 0.425 GeV^2. The x_L distribution of the neutrons is measured in bins of t. The (1-x_L) distributions in the bins of t studied satisfy a power law dN/dx_L ~ (1-x_L)^a(t), with the powers a(t) following a linear function of t: a(t) = 1.08 +/- 0.08(stat.) +0.15/-0.28(syst.) - [2.78 +/- 0.32(stat.) +0.51/-0.47(syst.) GeV^-2]t. This result is consistent with the expectations of pion-exchange models, in which the incoming proton fluctuates to a neutron-pion state and the electron interacts with the pion.

  7. Pion vector form factor from lattice QCD at the physical point

    Science.gov (United States)

    Alexandrou, C.; Bacchio, S.; Dimopoulos, P.; Finkenrath, J.; Frezzotti, R.; Jansen, K.; Kostrzewa, B.; Mangin-Brinet, M.; Sanfilippo, F.; Simula, S.; Urbach, C.; Wenger, U.; ETM Collaboration

    2018-01-01

    We present an investigation of the electromagnetic pion form factor, Fπ(Q2) , at small values of the four-momentum transfer Q2 (≲0.25 GeV2), based on the gauge configurations generated by the European Twisted Mass Collaboration with Nf=2 twisted-mass quarks at maximal twist including a clover term. Momentum is injected using nonperiodic boundary conditions and the calculations are carried out at a fixed lattice spacing (a ≃0.09 fm ) and with pion masses equal to its physical value, 240 MeV and 340 MeV. Our data are successfully analyzed using chiral perturbation theory at next-to-leading order in the light-quark mass. For each pion mass two different lattice volumes are used to take care of finite size effects. Our final result for the squared charge radius is ⟨r2⟩π=0.443 (29 ) fm2, where the error includes several sources of systematic errors except the uncertainty related to discretization effects. The corresponding value of the SU(2) chiral low-energy constant ℓ¯6 is equal to ℓ¯6=16.2 (1.0 ).

  8. Pion and kaon correlations in high energy heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K.L.; Wolf, K.L.

    1996-12-31

    Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV {sup 208}Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered {sup 208}Pb + Pb collisions. An upgraded multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au+Au reaction, taken with full event characterization. 35 refs., 15 figs., 5 tabs.

  9. Pion correlations and calorimeter design for high energy heavy ion collisions. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K.L.

    1997-04-01

    Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV {sup 208}Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered {sup 208}Pb + Pb collisions. An updated multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au + Au reaction, taken with full event characterization.

  10. Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

    Energy Technology Data Exchange (ETDEWEB)

    Yao, De-Liang [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Siemens, D. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Bernard, V. [Groupe de Physique Théorique, Institut de Physique Nucléaire, UMR 8606,CNRS, University Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex (France); Epelbaum, E. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Gasparyan, A.M. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); SSC RF ITEP, Bolshaya Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Gegelia, J. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Tbilisi State University, 0186 Tbilisi (Georgia); Krebs, H. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Meißner, Ulf-G. [Helmholtz Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2016-05-05

    We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P-partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.

  11. Event-by-event charged-neutral fluctuations in Pb+Pb collisions at 158 A GeV

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, M.M. [University of Panjab, Chandigarh 160014 (India); Ahammed, Z. [Variable Energy Cyclotron Centre, Calcutta 700 064 (India); Angelis, A.L.S. [University of Geneva, CH-1211 Geneva 4 (Switzerland); Antonenko, V. [RRC Kurchatov Institute, RU-123182 Moscow (Russian Federation); Arefiev, V.; Astakhov, V.; Avdeitchikov, V. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Awes, T.C. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States); Baba, P.V.K.S.; Badyal, S.K. [University of Jammu, Jammu 180001 (India); Bathe, S. [University of Muenster, D-48149 Muenster (Germany); Batiounia, B. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Bernier, T. [SUBATECH, Ecole des Mines, Nantes (France); Bhalla, K.B. [University of Rajasthan, Jaipur 302004, Rajasthan (India); Bhatia, V.S. [University of Panjab, Chandigarh 160014 (India); Blume, C.; Bucher, D.; Buesching, H. [University of Muenster, D-48149 Muenster (Germany); Carlen, L. [Lund University, SE-221 00 Lund (Sweden); Chattopadhyay, S. [Variable Energy Cyclotron Centre, Calcutta 700 064 (India)

    2011-07-11

    Charged particles and photons have been measured in central Pb + Pb collisions at 158 A GeV in a common ({eta}-{phi})-phase space region in the WA98 experiment at the CERN SPS. The measured distributions have been analyzed to quantify the frequency with which phase space regions of varying sizes have either small or large neutral pion fraction. The measured results are compared with VENUS model simulated events and with mixed events. Events with both large and small charged-neutral fluctuations are observed to occur more frequently than expected statistically, as deduced from mixed events, or as predicted by model simulations, with the difference becoming more prominent with decreasing size of the {Delta}{eta}-{Delta}{phi} region.

  12. Event-by-event charged-neutral fluctuations in Pb+Pb collisions at 158 A~GeV

    CERN Document Server

    Aggarwal, M.M.; Angelis, A.L.S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bucher, D.; Busching, H.; Carlen, L.; Chattopadhyay, S.; Decowski, M.P.; Delagrange, H.; Donni, P.; Dutta Majumdar, M.R.; El Chenawi, K.; Dubey, A.K.; Enosawa, K.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Gupta, R.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Karadjev, K.; Karpio, K.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kurata, M.; Lebedev, A.; Liu, H.; Lohner, H.; Luquin, L.; Mahapatra, D.P.; Manko, V.; Martin, M.; Martinez, G.; Maximov, A.; Miake, Y.; Mishra, G.C.; Mohanty, B.; Mora, M.J.; Morrison, D.; Moukhanova, T.; Mukhopadhyay, D.S.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nilsson, P.; Nishimura, S.; Nomokonov, P.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Pavliouk, S.; Peitzmann, T.; Peressounko, D.; Petracek, V.; Pinanaud, W.; Plasil, F.; Purschke, M.L.; Rak, J.; Raniwala, R.; Raniwala, S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Roy, C.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.R.; Schutz, Y.; Shabratova, G.; Shah, T.H.; Sibiriak, I.; Siemiarczuk, T.; Silvermyr, D.; Sinha, B.C.; Slavine, N.; Soderstrom, K.; Sood, G.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Sumbera, M.; Svensson, T.; Tsvetkov, A.; Tykarski, L.; van de Pijll, E.C.; van Eijndhoven, N.; van Nieuwenhuizen, G.J.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.; Voros, S.; Wyslouch, B.; Young, G.R.

    2011-01-01

    Charged particles and photons have been measured in central Pb+Pb collisions at 158 A GeV in a common ($\\eta$ - $\\phi$)-phase space region in the WA98 experiment at the CERN SPS. The measured distributions have been analyzed %using the sliding window method in order to quantify the frequency with which phase space regions of varying sizes have either small or large neutral pion fraction. The measured results are compared with VENUS model simulated events and with mixed events. Events with both large and small charged-neutral fluctuations are observed to occur more frequently than expected statistically, as deduced from mixed events, or as predicted by model simulations, with the difference becoming more prominent with decreasing size of the $\\Delta\\eta$ - $\\Delta\\phi$ region.

  13. Two-pion Bose-Einstein correlations in central PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Aamodt, K.; Adamova, D.; Adare, A.M.; Aggarwal, M.M.; Aglieri Rinella, G.; Agocs, A.G.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A.Ahmad; Ahn, S.U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Molina, R.Alfaro; Alici, A.; Alkin, A.; Almaraz Avina, E.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anson, C.; Anticic, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshauser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I.C.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T.C.; Aysto, J.; Azmi, M.D.; Bach, M.; Badala, A.; Baek, Y.W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Ferroli, R.Baldini; Baldisseri, A.; Baldit, A.; Ban, J.; Barbera, R.; Barile, F.; Barnafoldi, G.G.; Barnby, L.S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I.G.; Beck, H.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdermann, E.; Berdnikov, Y.; Betev, L.; Bhasin, A.; Bhati, A.K.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielcik, J.; Bielcikova, J.; Bilandzic, A.; Biolcati, E.; Blanc, A.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bock, N.; Bogdanov, A.; Boggild, H.; Bogolyubsky, M.; Boldizsar, L.; Bombara, M.; Bombonati, C.; Book, J.; Borel, H.; Bortolin, C.; Bose, S.; Bossu, F.; Botje, M.; Bottger, S.; Boyer, B.; Braun-Munzinger, P.; Bravina, L.; Bregant, M.; Breitner, T.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G.E.; Budnikov, D.; Buesching, H.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carminati, F.; Casanova Diaz, A.; Caselle, M.; Castillo Castellanos, J.; Catanescu, V.; Cavicchioli, C.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J.L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chiavassa, E.; Chibante Barroso, V.; Chinellato, D.D.; Chochula, P.; Chojnacki, M.; Christakoglou, P.; Christensen, C.H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Coffin, J.P.; Coli, S.; Conesa Balbastre, G.; Conesa del Valle, Z.; Constantin, P.; Contin, G.; Contreras, J.G.; Cormier, T.M.; Corrales Morales, Y.; Cortes Maldonado, I.; Cortese, P.; Cosentino, M.R.; Costa, F.; Cotallo, M.E.; Crescio, E.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; D'Erasmo, G.; Dainese, A.; Dalsgaard, H.H.; Danu, A.; Das, D.; Das, I.; Dash, A.; Dash, S.; De, S.; De Azevedo Moregula, A.; de Barros, G.O.V.; De Caro, A.; De Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Remigis, R.; de Rooij, R.; Delagrange, H.; Delgado Mercado, Y.; Dellacasa, G.; Deloff, A.; Demanov, V.; Denes, E.; Deppman, A.; Di Bari, D.; Di Giglio, C.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Dietel, T.; Divia, R.; Djuvsland, O.; Dobrin, A.; Dobrowolski, T.; Dominguez, I.; Donigus, B.; Dordic, O.; Driga, O.; Dubey, A.K.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A.K.; Dutta Majumdar, M.R.; Elia, D.; Emschermann, D.; Engel, H.; Erdal, H.A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evrard, S.; Eyyubova, G.; Fabjan, C.W.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fedunov, A.; Fehlker, D.; Fekete, V.; Felea, D.; Feofilov, G.; Fernandez Tellez, A.; Ferretti, A.; Ferretti, R.; Figueredo, M.A.S.; Filchagin, S.; Fini, R.; Finogeev, D.; Fionda, F.M.; Fiore, E.M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Fragkiadakis, M.; Frankenfeld, U.; Fuchs, U.; Furano, F.; Furget, C.; Fusco Girard, M.; Gaardhoje, J.J.; Gadrat, S.; Gagliardi, M.; Gago, A.; Gallio, M.; Ganoti, P.; Garabatos, C.; Gemme, R.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Girard, M.R.; Giraudo, G.; Giubellino, P.; Gladysz-Dziadus, E.; Glassel, P.; Gomez, R.; Gonzalez-Trueba, L.H.; Gonzalez-Zamora, P.; Gonzalez Santos, H.; Gorbunov, S.; Gotovac, S.; Grabski, V.; Grajcarek, R.; Gramling, J.L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J.F.; Grossiord, J.Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerra Gutierrez, C.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Gutbrod, H.; Haaland, O.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Harris, J.W.; Hartig, M.; Hasch, D.; Hasegan, D.; Hatzifotiadou, D.; Hayrapetyan, A.; Heide, M.; Heinz, M.; Helstrup, H.; Herghelegiu, A.; Hernandez, C.; Herrera Corral, G.; Herrmann, N.; Hetland, K.F.; Hicks, B.; Hille, P.T.; Hippolyte, B.; Horaguchi, T.; Hori, Y.; Hristov, P.; Hrivnacova, I.; Huang, M.; Huber, S.; Humanic, T.J.; Hwang, D.S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G.M.; Innocenti, P.G.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Jacholkowski, A.; Jacobs, P.M.; Jancurova, L.; Jangal, S.; Janik, R.; Jayarathna, S.P.; Jena, S.; Jirden, L.; Jones, G.T.; Jones, P.G.; Jovanovic, P.; Jung, H.; Jung, W.; Jusko, A.; Kalcher, S.; Kalinak, P.; Kalisky, M.; Kalliokoski, T.; Kalweit, A.; Kamermans, R.; Kanaki, K.; Kang, E.; Kang, J.H.; Kaplin, V.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Khan, M.M.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D.J.; Kim, D.S.; Kim, D.W.; Kim, H.N.; Kim, J.H.; Kim, J.S.; Kim, M.; Kim, M.; Kim, S.; Kim, S.H.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J.L.; Klein, J.; Klein-Bosing, C.; Kliemant, M.; Klovning, A.; Kluge, A.; Knichel, M.L.; Koch, K.; Kohler, M.K.; Kolevatov, R.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskih, A.; Kornas, E.; Kottachchi Kankanamge Don, C.; Kour, R.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kozlov, K.; Kral, J.; Kralik, I.; Kramer, F.; Kraus, I.; Krawutschke, T.; Kretz, M.; Krivda, M.; Krumbhorn, D.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucheriaev, Y.; Kuhn, C.; Kuijer, P.G.; Kurashvili, P.; Kurepin, A.; Kurepin, A.B.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kweon, M.J.; Kwon, Y.; La Rocca, P.; Ladron de Guevara, P.; Lafage, V.; Lara, C.; Larsen, D.T.; Lazzeroni, C.; Le Bornec, Y.; Lea, R.; Lee, K.S.; Lee, S.C.; Lefevre, F.; Lehnert, J.; Leistam, L.; Lenhardt, M.; Lenti, V.; Leon Monzon, I.; Leon Vargas, H.; Levai, P.; Li, X.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M.A.; Liu, L.; Loggins, V.R.; Loginov, V.; Lohn, S.; Lohner, D.; Loizides, C.; Lopez, X.; Lopez Noriega, M.; Lopez Torres, E.; Lovhoiden, G.; Lu, X.G.; Luettig, P.; Lunardon, M.; Luparello, G.; Luquin, L.; Luzzi, C.; Ma, K.; Ma, R.; Madagodahettige-Don, D.M.; Maevskaya, A.; Mager, M.; Mahapatra, D.P.; Maire, A.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Mares, J.; Margagliotti, G.V.; Margotti, A.; Marin, A.; Martashvili, I.; Martinengo, P.; Martinez, M.I.; Martinez Davalos, A.; Martinez Garcia, G.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastromarco, M.; Mastroserio, A.; Matthews, Z.L.; Matyja, A.; Mayani, D.; Mazza, G.; Mazzoni, M.A.; Meddi, F.; Menchaca-Rocha, A.; Mendez Lorenzo, P.; Mercado Perez, J.; Mereu, P.; Miake, Y.; Midori, J.; Milano, L.; Milosevic, J.; Mischke, A.; Miskowiec, D.; Mitu, C.; Mlynarz, J.; Mohanty, B.; Molnar, L.; Montano Zetina, L.; Monteno, M.; Montes, E.; Morando, M.; Moreira De Godoy, D.A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muller, H.; Muhuri, S.; Munhoz, M.G.; Munoz, J.; Musa, L.; Musso, A.; Nandi, B.K.; Nania, R.; Nappi, E.; Nattrass, C.; Navach, F.; Navin, S.; Nayak, T.K.; Nazarenko, S.; Nazarov, G.; Nedosekin, A.; Nendaz, F.; Newby, J.; Nicassio, M.; Nielsen, B.S.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B.S.; Nilsson, M.S.; Noferini, F.; Nooren, G.; Novitzky, N.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Obayashi, H.; Ochirov, A.; Oeschler, H.; Oh, S.K.; Oleniacz, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Ostrowski, P.; Otterlund, I.; Otwinowski, J.; Ovrebekk, G.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Paic, G.; Painke, F.; Pajares, C.; Pal, S.; Pal, S.K.; Palaha, A.; Palmeri, A.; Pappalardo, G.S.; Park, W.J.; Paticchio, V.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Peresunko, D.; Perez Lara, C.E.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Peters, A.J.; Petracek, V.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Piccotti, A.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piuz, F.; Piyarathna, D.B.; Platt, R.; Ploskon, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P.L.M.; Poghosyan, M.G.; Polak, K.; Polichtchouk, B.; Pop, A.; Pospisil, V.; Potukuchi, B.; Prasad, S.K.; Preghenella, R.; Prino, F.; Pruneau, C.A.; Pshenichnov, I.; Puddu, G.; Pulvirenti, A.; Punin, V.; Putis, M.; Putschke, J.; Quercigh, E.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Rademakers, O.; Radomski, S.; Raiha, T.S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Ramirez Reyes, A.; Rammler, M.; Raniwala, R.; Raniwala, S.; Rasanen, S.S.; Read, K.F.; Real, J.S.; Redlich, K.; Renfordt, R.; Reolon, A.R.; Reshetin, A.; Rettig, F.; Revol, J.P.; Reygers, K.; Ricaud, H.; Riccati, L.; Ricci, R.A.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rodriguez Cahuantzi, M.; Rohr, D.; Rohrich, D.; Romita, R.; Ronchetti, F.; Rosinsky, P.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roukoutakis, F.; Rousseau, S.; Roy, C.; Roy, P.; Rubio Montero, A.J.; Rui, R.; Rusanov, I.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Safarik, K.; Sahoo, R.; Sahu, P.K.; Saiz, P.; Sakai, S.; Sakata, D.; Salgado, C.A.; Samanta, T.; Sambyal, S.; Samsonov, V.; Sandor, L.; Sandoval, A.; Sano, M.; Sano, S.; Santo, R.; Santoro, R.; Sarkamo, J.; Saturnini, P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R.P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H.R.; Schreiner, S.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P.A.; Scott, R.; Segato, G.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Shabratova, G.; Shahoyan, R.; Sharma, N.; Sharma, S.; Shigaki, K.; Shimomura, M.; Shtejer, K.; Sibiriak, Y.; Siciliano, M.; Sicking, E.; Siemiarczuk, T.; Silenzi, A.; Silvermyr, D.; Simonetti, G.; Singaraju, R.; Singh, R.; Sinha, B.C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T.B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R.; Sogaard, C.; Soloviev, A.; Soltz, R.; Son, H.; Song, M.; Soos, C.; Soramel, F.; Spyropoulou-Stassinaki, M.; Srivastava, B.K.; Stachel, J.; Stan, I.; Stefanek, G.; Stefanini, G.; Steinbeck, T.; Stenlund, E.; Steyn, G.; Stocco, D.; Stock, R.; Stolpovskiy, M.; Strmen, P.; Suaide, A.A.P.; Subieta Vasquez, M.A.; Sugitate, T.; Suire, C.; Sumbera, M.; Susa, T.; Swoboda, D.; Symons, T.J.M.; Szanto de Toledo, A.; Szarka, I.; Szostak, A.; Tagridis, C.; Takahashi, J.; J.Tapia Takaki, D.; Tauro, A.; Tavlet, M.; Tejeda Munoz, G.; Telesca, A.; Terrevoli, C.; Thader, J.; Thomas, D.; Thomas, J.H.; Tieulent, R.; Timmins, A.R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Tosello, F.; Traczyk, T.; Truesdale, D.; Trzaska, W.H.; Tumkin, A.; Turrisi, R.; Turvey, A.J.; Tveter, T.S.; Ulery, J.; Ullaland, K.; Uras, A.; Urban, J.; Urciuoli, G.M.; Usai, G.L.; Vacchi, A.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Kolk, N.; van Leeuwen, M.; Vande Vyvre, P.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Vikhlyantsev, O.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y.P.; Vodopyanov, A.; Voloshin, K.; Voloshin, S.; Volpe, G.; von Haller, B.; Vranic, D.; Vrlakova, J.; Vulpescu, B.; Wagner, B.; Wagner, V.; Wan, R.; Wang, D.; Wang, Y.; Wang, Y.; Watanabe, K.; Wessels, J.P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, A.; Wilk, G.; Williams, M.C.S.; Windelband, B.; Yang, H.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yokoyama, H.; Yoo, I.K.; Yuan, X.; Yushmanov, I.; Zabrodin, E.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Zavada, P.; Zbroszczyk, H.; Zelnicek, P.; Zenin, A.; Zgura, I.; Zhalov, M.; Zhang, X.; Zhou, D.; Zhu, X.; Zichichi, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.

    2013-07-16

    The first measurement of two-pion Bose--Einstein correlations in central PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.

  14. Neutrality Versus Materiality: A Thermodynamic Theory of Neutral Surfaces

    Directory of Open Access Journals (Sweden)

    Rémi Tailleux

    2016-09-01

    Full Text Available In this paper, a theory for constructing quasi-neutral density variables γ directly in thermodynamic space is formulated, which is based on minimising the absolute value of a purely thermodynamic quantity J n . Physically, J n has a dual dynamic/thermodynamic interpretation as the quantity controlling the energy cost of adiabatic and isohaline parcel exchanges on material surfaces, as well as the dependence of in-situ density on spiciness, in a description of water masses based on γ, spiciness and pressure. Mathematically, minimising | J n | in thermodynamic space is showed to be equivalent to maximising neutrality in physical space. The physics of epineutral dispersion is also reviewed and discussed. It is argued, in particular, that epineutral dispersion is best understood as the aggregate effect of many individual non-neutral stirring events (being understood here as adiabatic and isohaline events with non-zero buoyancy, so that it is only the net displacement aggregated over many events that is approximately neutral. This new view resolves an apparent paradox between the focus in neutral density theory on zero-buoyancy motions and the overwhelming evidence that lateral dispersion in the ocean is primarily caused by non-zero buoyancy processes such as tides, residual currents and sheared internal waves. The efficiency by which a physical process contributes to lateral dispersion can be characterised by its energy signature, with those processes releasing available potential energy (negative energy cost being more efficient than purely neutral processes with zero energy cost. The latter mechanism occurs in the wedge of instability, and its source of energy is the coupling between baroclinicity, thermobaricity, and density compensated temperature/salinity anomalies. Such a mechanism, which can only exist in a salty ocean, is speculated to be important for dissipating spiciness anomalies and neutral helicity. The paper also discusses potential

  15. Net Neutrality: Background and Issues

    National Research Council Canada - National Science Library

    Gilroy, Angele A

    2006-01-01

    .... The move to place restrictions on the owners of the networks that compose and provide access to the Internet, to ensure equal access and nondiscriminatory treatment, is referred to as "net neutrality...

  16. Incomplete Neutralization and Deviation from Sigmoidal Neutralization Curves for HIV Broadly Neutralizing Monoclonal Antibodies.

    Directory of Open Access Journals (Sweden)

    Laura E McCoy

    2015-08-01

    Full Text Available The broadly neutralizing HIV monoclonal antibodies (bnMAbs PG9, PG16, PGT151, and PGT152 have been shown earlier to occasionally display an unusual virus neutralization profile with a non-sigmoidal slope and a plateau at <100% neutralization. In the current study, we were interested in determining the extent of non-sigmoidal slopes and plateaus at <100% for HIV bnMAbs more generally. Using both a 278 panel of pseudoviruses in a CD4 T-cell (U87.CCR5.CXCR4 assay and a panel of 117 viruses in the TZM-bl assay, we found that bnMAbs targeting many neutralizing epitopes of the spike had neutralization profiles for at least one virus that plateaued at <90%. Across both panels the bnMAbs targeting the V2 apex of Env and gp41 were most likely to show neutralization curves that plateaued <100%. Conversely, bnMAbs targeting the high-mannose patch epitopes were less likely to show such behavior. Two CD4 binding site (CD4bs Abs also showed this behavior relatively infrequently. The phenomenon of incomplete neutralization was also observed in a large peripheral blood mononuclear cells (PBMC-grown molecular virus clone panel derived from patient viral swarms. In addition, five bnMAbs were compared against an 18-virus panel of molecular clones produced in 293T cells and PBMCs and assayed in TZM-bl cells. Examples of plateaus <90% were seen with both types of virus production with no consistent patterns observed. In conclusion, incomplete neutralization and non-sigmoidal neutralization curves are possible for all HIV bnMAbs against a wide range of viruses produced and assayed in both cell lines and primary cells with implications for the use of antibodies in therapy and as tools for vaccine design.

  17. Weak neutral-current interactions

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, R.M.

    1978-08-01

    The roles of each type of experiment in establishing uniquely the values of the the neutral-current couplings of u and d quarks are analyzed together with their implications for gauge models of the weak and electromagnetic interactions. An analysis of the neutral-current couplings of electrons and of the data based on the assumption that only one Z/sup 0/ boson exists is given. Also a model-independent analysis of parity violation experiments is discussed. 85 references. (JFP)

  18. The Economics of Net Neutrality

    OpenAIRE

    Hahn, Robert W.; Wallsten, Scott

    2006-01-01

    This essay examines the economics of "net neutrality" and broadband Internet access. We argue that mandating net neutrality would be likely to reduce economic welfare. Instead, the government should focus on creating competition in the broadband market by liberalizing more spectrum and reducing entry barriers created by certain local regulations. In cases where a broadband provider can exercise market power the government should use its antitrust enforcement authority to police anticompetitiv...

  19. Vendor neutral archive in PACS

    Directory of Open Access Journals (Sweden)

    Tapesh Kumar Agarwal

    2012-01-01

    Full Text Available An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. "Vendor neutral" may not be a suitable term, and "architecture neutral," "PACS neutral," "content neutral," or "third-party neutral" are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe.

  20. phi-meson photoproduction on Hydrogen in the neutral decay mode

    Energy Technology Data Exchange (ETDEWEB)

    Seraydaryan, Helena [ODU; Amaryan, Moscov J. [ODU; Gavalian, Gagik [JLAB; Baghdasaryan, Hovhannes A. [UVA; Weinstein, Larry [ODU

    2014-05-01

    We report the first measurement of the photoproduction cross section of the $\\phi$ meson in its neutral decay mode in the reaction $\\gamma p \\to p\\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \\le E_\\gamma \\le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \\phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\\gamma p \\to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\\phi$ photoproduction.

  1. Discovery of omega meson, first neutral vector meson. [Personal account by researcher

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    A personal account of the discovery of the ..omega.. meson is given by researcher B. Maglich. His account includes such topics as early and unsuccessful searches for a neutral vector meson (by himself and others), eventual discovery of the rho meson, the Goldhaber effect, and the observation and characterization of the ..omega.. meson. Explanatory physics notes on electromagnetic structure experiments and the determination of the quantum numbers of the ..omega.. meson are provided for nonspecialists. Also included are an outline of the relation between vector mesons and nuclear forces, a reprint of the Physical Review Letter on Evidence for a T = 0 three-pion resonance, and a scientific autobiography of the researcher. 14 figures, 1 table. (RWR)

  2. A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, Katsuki [Kyoto Univ. (Japan)

    2009-01-01

    Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for vμ → vx oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (vμN → μ-+) and coherent pion production interacting with the entire nucleus (vμA → μ-+), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, vμ 12C → μ-12+, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 1020 protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 1020 protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio

  3. Neutral gas depletion in low temperature plasma

    Science.gov (United States)

    Fruchtman, A.

    2017-11-01

    Neutral depletion can significantly affect the steady state of low temperature plasmas. Processes that lead to neutral depletion and the resulting plasma–neutrals steady state are reviewed. Two such processes are due to collisions of neutrals with plasma. One process is the drag by ions that collide with neutrals and push them towards the wall. Another process is neutral-gas heating by collisions with plasma that makes the gas hotter at the discharge center. These processes, which usually occur under (static) pressure balance between plasma and neutrals, are called here ‘neutral pumping’. When collisions are negligible, neutrals that move ballistically between the chamber walls are depleted through ionization, a process called here ‘ion pumping’. The effect of the magnetic field on neutral depletion is explored in plasma in which the dynamics is governed by cross-field diffusion. Finally, neutral depletion in a flowing plasma is analyzed.

  4. Kaon production and kaon to pion ratio in Au+Au collisions at $\\sqrt {s_{NN}} = 130 GeV

    CERN Document Server

    Adler, C; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Caines, H; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Deng, W S; Derevshchikov, A A; Didenko, L; Dietel, T; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Filimonov, K; Finch, E; Fisyak, Yu; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Krämer, M; Kravtsov, P; Krüger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Le Vine, M J; Lebedev, A; Lednicky, R; Leontiev, V M; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Lo Curto, G; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Majka, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moore, C F; Morozov, V; Munhoz, M G; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevozchikov, V; Peryt, W; Petrov, V A; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E V; Prindle, D; Pruneau, C A; Putschke, J; Rai, G; Rakness, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Rykov, V; Sakrejda, I; Salur, S; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schröder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D M; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimansky, S S; Shvetcov, V S; Skoro, G P; Smirnov, N; Snellings, R; Sørensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Struck, C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thomas, J H; Thompson, M; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; Van der Molen, A M; Vasilevski, I M; Vasilev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevsky, Yu V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N; De Moura, M M; Szanto de Toledo, A; De la Barca-Sanchez, M C; 10.1016/j.physletb.2004.06.044

    2004-01-01

    Midrapidity transverse mass spectra and multiplicity densities of charged and neutral kaons are reported for Au+Au collisions at square root s/sub NN/=130 GeV at RHIC. The spectra are exponential in transverse mass, with an inverse slope of about 280 MeV in central collisions. The multiplicity densities for these particles scale with the negative hadron pseudorapidity density. The charged kaon to pion ratios are K/sup +// pi /sup -/=0.161+or-0.002(stat)+or-0.024(syst) and K/sup -// pi /sup -/=0.146+or-0.002(stat)+or-0.022(syst) for the most central collisions. The K/sup +// pi /sup -/ ratio is lower than the same ratio observed at the SPS while the K/sup -// pi /sup -/ is higher than the SPS result. The ratios are enhanced by about 50% relative to p+p and p+p collision data at similar energies.

  5. Optical Neutrality: Invisibility without Cloaking

    OpenAIRE

    Hodges, Reed; Dean, Cleon; Durach, Maxim

    2016-01-01

    We show that it is possible to design an invisible wavelength-sized metal-dielectric metamaterial object without evoking cloaking. Our approach is an extension of the neutral inclusion concept by Zhou and Hu [Phys.Rev.E 74, 026607 (2006)] to Mie scatterers. We demonstrate that an increase of metal fraction in the metamaterial leads to a transition from dielectric-like to metal-like scattering, which proceeds through invisibility or optical neutrality of the scatterer. Formally this is due to ...

  6. Modification of pion pairs in nuclear matter; Modifikationen von Pionenpaaren in Kernmaterie

    Energy Technology Data Exchange (ETDEWEB)

    Gregor, Ralf

    2007-07-18

    In this work the quasifree photoproduction of pion pairs on bound nucleons is analyzed for the solid targets carbon, calcium and lead. These measurements allow an isospin dependent determination of the in medium properties of pion pairs. The invariant mass distributions showed a shift in strength towards the threshold region with increasing atomic number of the targets in case of an isoscalar {pi}{pi} meson system. According to theoretical predictions this effect was interpreted as a positive signature of a partial restoration of chiral symmetry. A pioneering experiment with photon beams was performed by the TAPS collaboration at the accelerator facility MAMI-B in Mainz in 1995. This measurement observed an invariant mass shift of the isoscalar {pi}{sup 0}{pi}{sup 0} channel with increasing atomic number. In the {pi}{sup {+-}}{pi}{sup 0} channel this effect was not observed. This observation confirmed the former experiments, since final state interactions of the pions would affect in first order both isospin channels in a similar way. Due to the poor statistics, the significance of the data was however limited. The experiment described in this work reached a much higher statistical significance, allowing a review of the old data and a study of the dependence of the signal from parameters like the momenta of the {pi}{pi} system or the single pions. In this experiment, the TAPS detector was used as a forward wall in combination with the Crystal Ball detector to achieve a 4{pi} solid angle coverage for photon detection at the MAMI accelerator facility. The new readout electronics for the BaF{sub 2} crystals was used for the first time. The new data analysis confirms the previously measured and published data. However, the shift of the invariant {pi}{sup 0}{pi}{sup 0} mass to the threshold region is less pronounced than in the published data. By performing cuts on the individual pion momenta, resulting in a maximum mean free path of the pions, the shift towards lower

  7. Low momentum transfer measurements of pion electroproduction and virtual Compton scattering at the Delta resonance

    Energy Technology Data Exchange (ETDEWEB)

    Blomberg, Adam [Temple Univ., Philadelphia, PA (United States)

    2016-12-01

    Non-spherical components of the nucleon wave function are measured through p(e,e'p)π0 experiment at the Δ+(1232) resonance for Q2 = 0.04, 0.09, and 0.13 (GeV=c)2 utilizing the Jefferson National Accelerator Facility (JLab) pulsed beam and Hall A spectrometers. The new data extend the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements indicate that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements. The Coulomb to magnetic multipole ratio (CMR) and generalized polarizability (GP) of the nucleon are also measured through virtual Compton scattering (VCS) for Q2 = 0.2(GeV=c)2 utilizing the Mainz Microtron (MAMI) continuous beam and A1 spectrometers. This data represents the first low Q2 GP measurement at the Δ+(1232) resonance. The GP measurement explores a region where previous data and theoretical calculations disagree. The CMR measurement will be the first VCS extraction to compare with world data generated through pion electroproduction. The Dispersion Relation (DR) model used for the VCS extraction provides a new theoretical framework for the data signal and backgrounds that is largely independent from the pion electroproduction models. The independence of the DR from the traditional models provides a strong crosscheck on the ability of the models to isolate the data signal.

  8. Photo- and pion electroproduction in chiral effective field theory; Photo- und Elektropionproduktion in chiraler effektiver Feldtheorie

    Energy Technology Data Exchange (ETDEWEB)

    Hilt, Marius

    2011-12-13

    This thesis is concerned with pion photoproduction (PPP) and pion electroproduction (PEP) in the framework of manifestly Lorentz-invariant baryon chiral perturbation theory. For that purpose two different approaches are used. Firstly, a one-loop-order calculation up to chiral order O(q{sup 4}) including pions and nucleons as degrees of freedom, is performed to describe the energy dependence of the reactions over a large range. To improve the dependence on the virtuality of the photon in PEP, in a second approach vector mesons are included as explicit degrees of freedom. The latter calculation includes one-loop contributions up to chiral order O(q{sup 3}). Only three of the four physical processes of PPP and PEP can be accessed experimentally. These reactions are measured at several different facilities, e.g. Mainz, Bonn, or Saskatoon. The data obtained there are used to explore the limits of chiral perturbation theory. This thesis is the first complete manifestly Lorentz-invariant calculation up to order O(q{sup 4}) for PPP and PEP, and the first calculation ever for these processes including vector mesons explicitly. Beside the calculation of physical observables, a partial wave decomposition is performed and the most important multipoles are analyzed. They may be extracted from the calculated amplitudes and allow one to examine the nucleon and {delta} resonances. The number of diagrams one has to calculate is very large. In order to handle these expressions, several routines were developed for the computer algebra system Mathematica. For the multipole decomposition, two different programs are used. On the one hand, a modified version of the so-called {chi}MAID has been employed. On the other hand, similar routines were developed for Mathematica. In the end, the different calculations are compared with respect to their applicability to PPP and PEP.

  9. Pion and Kaon structure function measurements at Jefferson Lab 12 GeV and the Electron-Ion Collider

    Science.gov (United States)

    Vargas, Andres; Horn, Tanja; Trotta, Richard

    2017-09-01

    The lightest mesons, Pions and Kaons play a fundamental role in the understanding of hadronic mass. The 12 GeV JLab will address some questions, but to ultimately understand the role of sea quarks and gluons in pion and kaon masses the wide kinematic reach in the longitudinal momentum fraction as well as in the four-momentum transfer, as enabled by the Electron-Ion Collider (EIC) is needed. In this talk, we present the current status of and projections for measurements of pion and kaon structure functions in the Jefferson Laboratory 12 GeV era and at the EIC. Supported in part by NSF Grants PHY1306227, PHY1306418 and PHY1530874.

  10. Pion pT Spectra in p+p Collisions as a Function of s and Event Multiplicity

    OpenAIRE

    Sett, Priyanka; Shukla, Prashant

    2014-01-01

    We study the charged pion transverse momentum (pT) spectra in p+p collisions as a function of collision energy s and event multiplicity using Tsallis distribution. This study gives an insight of the pion production process in p+p collisions. The study covers pion spectra measured in p+p collisions at SPS energies (6.27–17.27 GeV), RHIC energies (62.4 GeV and 200 GeV), and LHC energies (900 GeV, 2.76 TeV, and 7 TeV). The Tsallis parameters have been obtained and parameterized as a function of ...

  11. The transverse structure of the pion in momentum space inspired by the AdS/QCD correspondence

    Science.gov (United States)

    Bacchetta, Alessandro; Cotogno, Sabrina; Pasquini, Barbara

    2017-08-01

    We study the internal structure of the pion using a model inspired by the AdS/QCD correspondence. The holographic approach provides the light-front wave function (LFWF) for the leading Fock-state component of the pion. We adopt two different forms for the LFWF derived from the AdS/QCD soft-wall model, with free parameters fitted to the available experimental information on the pion electromagnetic form factor and the leading-twist parton distribution function. The intrinsic scale of the model is taken as an additional fit parameter. Within this framework, we provide predictions for the unpolarized transverse momentum dependent parton distribution (TMD), and discuss its property both at the scale of the model and after TMD evolution to higher scales that are relevant for upcoming experimental measurements.

  12. Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

    CERN Document Server

    Trassinelli, M; Borchert, G; Dax, A; Egger, J P; Gotta, D; Hennebach, M; Indelicato, P; Liu, Y -W; Manil, B; Nelms, N; Simons, L M; Wells, A

    2016-01-01

    The $5g-4f$ transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\\,bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077\\,$\\pm$\\,0.00018)\\,MeV/c$^{2}$ ($\\pm$\\,1.3ppm) is derived for the mass of the negatively charged pion, which is 4.2ppm larger than the present world average.

  13. Backward dispersion relations and pion-/sup 4/He phase-shift analyses

    CERN Document Server

    Dumbrajs, O V

    1979-01-01

    The usefulness of backward dispersion relations in nuclear physics is discussed. As an example, pion-/sup 4/He elastic scattering is considered. It is shown how the use of backward dispersion relations can help in reducing ambiguities of phase-shift analyses. In particular, the solution with the S-wave changing sign twice between 150 and 260 MeV and with the real part of the backward scattering amplitude becoming positive at approximately 140 MeV and exhibiting resonating behaviour has been suggested as the most probable one. (8 refs).

  14. Effect of isobars at finite temperature in pion condensation in 16O

    Directory of Open Access Journals (Sweden)

    R.K. Tripathi

    1983-01-01

    Full Text Available The role of Δ (1232 at finite temperature is considered in pion condensation in 16O. Taking into account the effect of the Δ's the free energy of the spin-isospin phase, where the spins of all the protons are oriented one way and those of neutrons in the opposite direction, is compared with the free energy of the normal phase. For higher temperatures (T> 15MeV the critical density of the phase transition increases with temperature. Smaller temperatures are found to contribute to the development of the condensate. The Δ's get increasingly more important with higher density and temperature.

  15. Pion Transition Form Factor at the Two-Loop Level VIS-À-VIS Experimental Data

    Science.gov (United States)

    Mikhailov, S. V.; Stefanis, N. G.

    We use light-cone QCD sum rules to calculate the pion-photon transition form factor, taking into account radiative corrections up to the next-to-next-to-leading order of perturbation theory. We compare the obtained predictions with all available experimental data from the CELLO, CLEO, and the BaBar Collaborations. We point out that the BaBar data are incompatible with the convolution scheme of QCD, on which our predictions are based, and can possibly be explained only with a violation of the factorization theorem. We pull together recent theoretical results and comment on their significance.

  16. Exclusive production of pion and kaon meson pairs in two photon collisions at LEP

    CERN Document Server

    Heister, A; Antonelli, A; Antonelli, M; Armstrong, S R; Awunor, O; Azzurri, P; Badaud, F; Bagliesi, G; Barate, R; Barklow, Timothy L; Bencivenni, G; Berkelman, K; Beuselinck, R; Blair, G A; Bloch-Devaux, B; Blondel, A; Blumenschein, U; Boccali, T; Bonissent, A; Booth, C N; Borean, C; Bossi, F; Boucrot, J; Bouhova-Thacker, E; Boumediene, D E; Bowdery, C K; Brandt, S; Bravo, S; Brient, J C; Brunelière, R; Buchmüller, O L; Böhrer, A; Callot, O; Cameron, W; Capon, G; Cartwright, S; Casado, M P; Cattaneo, M; Cavanaugh, R J; Cerutti, F; Chiarella, V; Chmeissani, M; Ciulli, V; Clarke, D P; Clerbaux, B; Clifft, R W; Colaleo, A; Colas, P; Combley, F; Cowan, G; Coyle, P; Cranmer, K; Creanza, D; Crespo, J M; Curtil, C; David, A; Davier, M; Davies, G; De Bonis, I; De Filippis, N; De Palma, M; Delaere, C; Dessagne, S; Dhamotharan, S; Dietl, H; Dissertori, G; Dornan, P J; Drevermann, H; Duflot, L; Décamp, D; Ealet, A; Edgecock, T R; Ellis, G; Fabbro, B; Falvard, A; Fayolle, D; Ferguson, D P S; Fernández-Bosman, M; Fernández, E; Finch, A J; Focardi, E; Forty, R W; Foster, F; Fouchez, D; Foà, L; Frank, M; Ganis, G; Gao, Y; García-Bellido, A; Garrido, L; Gay, P; Geweniger, C; Ghete, V M; Giammanco, A; Giannini, G; Gianotti, F; Giassi, A; Girone, M; Girtler, P; González, S; Goy, C; Green, M G; Grivaz, J F; Grupen, C; Hanke, P; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Harvey, J; Hayes, O J; He, H; Hepp, V; Hess, J; Heusse, P; Hill, R D; Hodgson, P N; Hu, H; Huang, X; Hughes, G; Hutchcroft, D E; Hölldorfer, F; Hüttmann, K; Iaselli, G; Jacholkowska, A; Jakobs, K; Janot, P; Jin, S; Jones, L T; Jones, R W L; Jost, B; Jousset, J; Jézéquel, S; Kado, M; Kayser, F; Kennedy, J; Kile, J; Kleinknecht, K; Kluge, E E; Kneringer, E; Kraan, A C; Kuhn, D; Kyriakis, A; Lançon, E; Laurelli, P; Lees, J P; Lehto, M H; Leibenguth, G; Lemaire, M C; Lemaître, V; Ligabue, F; Lin, J; Litke, A M; Locci, E; Lynch, J G; Lütjens, G; Machefert, F P; Maggi, G; Maggi, M; Mannocchi, G; Marinelli, N; Markou, C; Martin, F; Martínez, M; Mato, P; McNamara, P A; Medcalf, T; Merle, E; Messineo, A; Michel, B; Minard, M N; Misiejuk, A; Monteil, S; Moser, H G; Moutoussi, A; Murtas, G P; Männer, W; Müller, A S; Negus, P; Ngac, A; Nielsen, J; Nilsson, B S; Norton, P R; Nowell, J; Nuzzo, S; O'Shea, V; Ouyang, Q; Pacheco, A; Palla, Fabrizio; Pallin, D; Pan, Y B; Parrini, G; Pascolo, J M; Passalacqua, L; Payre, P; Pearson, M R; Perret, P; Pietrzyk, B; Prange, G; Putzer, A; Pérez, P; Pütz, J; Ragusa, F; Rander, J; Ranieri, A; Ranjard, F; Raso, G; Renk, B; Robertson, N A; Rolandi, Luigi; Rothberg, J E; Rougé, A; Rudolph, G; Ruggieri, F; Ruiz, H; Rutherford, S A; Sander, H G; Sanguinetti, G; Schael, S; Schlatter, W D; Schmeling, S; Sciabà, A; Sedgbeer, J K; Selvaggi, G; Serin, L; Settles, Ronald; Sguazzoni, G; Silvestris, L; Simopoulou, Errietta; Smizanska, M; Spagnolo, R; Stenzel, H; Strong, J A; Taylor, G; Teixeira-Dias, P; Tempesta, P; Tenchini, A; Teubert, F; Thompson, A S; Thompson, J C; Thompson, L F; Tilquin, A; Tittel, K; Tomalin, I R; Tricomi, A; Trocmé, B; Tuchming, B; Valassi, Andrea; Vallage, B; Vayaki, Anna; Veillet, J J; Venturi, P; Verdini, P G; Videau, H L; Videau, I; Villegas, M; Von Wimmersperg-Töller, J H; Wachsmuth, H W; Wang, T; Ward, J J; Wasserbaech, S R; White, R; Wiedenmann, W; Wolf, G; Wu, J; Wu Sau Lan; Wu, X; Wunsch, M; Xie, Y; Xu, R; Xue, S; Zachariadou, K; Zeitnitz, C; Zhang, J; Zhang, L; Zhao, W; Ziegler, T; Zito, G; Zobernig, G; van der Aa, O

    2003-01-01

    Exclusive production of $\\pi$ and K meson pairs in two photon collisions is measured with ALEPH data collected between 1992 and 2000. Cross sections are presented as a function of \\cos\\theta^* and invariant mass, for |\\cos\\theta^* |< 0.6 and invariant masses between 2.0 and 6.0 \\mathrm{GeV}/c^2 (2.25 and 4.0 \\mathrm{GeV}/c^2) for pions (kaons). The shape of the distributions are found to be well described by QCD predictions but the data have a significantly higher normalisation.

  17. Study of Proton and Pion Irradiated Silicon Pad Detectors with CV/IV and TCT measurements

    CERN Document Server

    Sumida, Hiroki

    2014-01-01

    The performance of silicon diodes in high energy physics experiments deteriorates with irradiation. Performance properties of proton and pion irradiated samples are studied with CV/IV and TCT measurements. CV/IV measurements offer the possibility to study the full depletion voltage, leakage current and effective doping concentration. TCT measurements are used to investigate the electric field, charge collection and type inversion in function of the fluence. An annealing study is performed with one 9.64E13 p/cm2 irradiated sample up to a total annealing time of 1167 min at 60C.

  18. Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

    Directory of Open Access Journals (Sweden)

    M. Trassinelli

    2016-08-01

    Full Text Available The 5g−4f transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen–oxygen mixture at 1.4 bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077 ± 0.00018 MeV/c2 (± 1.3 ppm is derived for the mass of the negatively charged pion, which is 4.2 ppm larger than the present world average.

  19. Extracting the σ-term from low-energy pion-nucleon scattering

    Science.gov (United States)

    Ruiz de Elvira, Jacobo; Hoferichter, Martin; Kubis, Bastian; Meißner, Ulf-G.

    2018-02-01

    We present an extraction of the pion-nucleon (π N) scattering lengths from low-energy π N scattering, by fitting a representation based on Roy–Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large π N σ-term, {σ }π N=58(5) {{MeV}}, in agreement with, albeit less precise than, the determination from pionic atoms.

  20. Photoneutron multiplicities of preactinide nuclei at energies above the pion threshold

    Energy Technology Data Exchange (ETDEWEB)

    Arruda-Neto, J.D.T.; Simionatto, S.; Likhachev, V.P.; Garcia, F.; Mesa, J. [Sao Paulo Univ., SP (Brazil). Phys. Inst.; Deppman, A. [INFN, Frascati (Italy). Lab. Nazionali di Frascati; Rodriguez, O.; Guzman, F. [Inst. Superior de Ciencia y Tecnologia Nucleares, Havana (Cuba)

    1998-08-17

    The average photoneutron multiplicities anti {nu} of Au, Ta and {sup 182}W were deduced from their previously measured excitation energies anti E{sub x}, from 160 to 250 MeV. A combined analysis of these data and those measured at Saclay up to 140 MeV allowed the extraction of information on anti E{sub x} at the ``pure evaporation`` and quasideuteron energy regions. A theoretical approach for the study of anti {nu} above 140 MeV, which incorporates photopion reabsorption processes by two-body, was proposed, allowing a tentative delineation of the pion mean free path in the nucleus. (orig.) 19 refs.

  1. Imaging dynamical chiral-symmetry breaking: pion wave function on the light front.

    Science.gov (United States)

    Chang, Lei; Cloët, I C; Cobos-Martinez, J J; Roberts, C D; Schmidt, S M; Tandy, P C

    2013-03-29

    We project onto the light front the pion's Poincaré-covariant Bethe-Salpeter wave function obtained using two different approximations to the kernels of quantum chromodynamics' Dyson-Schwinger equations. At an hadronic scale, both computed results are concave and significantly broader than the asymptotic distribution amplitude, φ(π)(asy)(x)=6x(1-x); e.g., the integral of φ(π)(x)/φ(π)(asy)(x) is 1.8 using the simplest kernel and 1.5 with the more sophisticated kernel. Independent of the kernels, the emergent phenomenon of dynamical chiral-symmetry breaking is responsible for hardening the amplitude.