Self-consistent descriptions of vector mesons in hot matter reexamined

International Nuclear Information System (INIS)

Riek, Felix; Knoll, Joern

2010-01-01

Technical concepts are presented that improve the self-consistent treatment of vector mesons in a hot and dense medium. First applications concern an interacting gas of pions and ρ mesons. As an extension of earlier studies, we thereby include random-phase-approximation-type vertex corrections and further use dispersion relations to calculate the real part of the vector-meson self-energy. An improved projection method preserves the four transversality of the vector-meson polarization tensor throughout the self-consistent calculations, thereby keeping the scheme void of kinematical singularities.

Light Vector Mesons in the Nuclear Medium

Energy Technology Data Exchange (ETDEWEB)

Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

2008-07-01

The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff

Interference in Exclusive Vector Meson Production in Heavy-Ion Collisions

International Nuclear Information System (INIS)

Klein, Spencer R.; Nystrand, Joakim

2000-01-01

Vector mesons are produced copiously in peripheral relativistic heavy-ion collisions. Virtual photons from one ion can fluctuate into quark-antiquark pairs and scatter from the second ion, emerging as vector mesons. The emitter and target are indistinguishable, so emission from the two ions will interfere. Vector mesons have negative parity so the interference is destructive, reducing the production of mesons with small transverse momentum. The mesons are short lived, and decay before emission from the two ions can overlap. However, the decay-product wave functions overlap and interfere since they are produced in an entangled state, providing an example of the Einstein-Podolsky-Rosen paradox. (c) 2000 The American Physical Society

Radiative decays of vector mesons in the chiral bag model

International Nuclear Information System (INIS)

Tabachenko, A.N.

1988-01-01

A new model of radiative π-meson decays of vector mesons in the chiral bag model is proposed. The quark-π-meson interaction has the form of a pseudoscalar coupling and is located on the bag surface. The vector meson decay width depends on the quark masses, the π-meson decay constant, the radius of the bag, and the free parameter Z 2 , which specifies the disappearance of the bag during the decay. The obtained results for the omega- and p-decay widths are in satisfactory agreement with the experiment

Hamiltonian lattice studies of chiral meson field theories

International Nuclear Information System (INIS)

Chin, S.A.

1998-01-01

The latticization of the non-linear sigma model reduces a chiral meson field theory to an O(4) spin lattice system with quantum fluctuations. The result is an interesting marriage between quantum many-body theory and classical spin systems. By solving the resulting lattice Hamiltonian by Monte Carlo methods, the dynamics and thermodynamics of pions can be determined non-perturbatively. In a variational 16 3 lattice study, the ground state chiral phase transition is shown to be first order. Moreover, as the chiral phase transition is approached, the mass gap of pionic collective modes with quantum number of the ω vector meson drops toward zero. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

Melting spectral functions of the scalar and vector mesons in a holographic QCD model

International Nuclear Information System (INIS)

Fujita, Mitsutoshi; Kikuchi, Toru; Fukushima, Kenji; Misumi, Tatsuhiro; Murata, Masaki

2010-01-01

We investigate the finite-temperature spectral functions of heavy quarkonia by using the soft-wall anti-de Sitter/QCD model. We discuss the scalar, the pseudoscalar, the vector, and the axial-vector mesons and compare their qualitative features of the melting temperature and growing width. We find that the axial-vector meson melts earlier than the vector meson, while there appears only a slight difference between the scalar and pseudoscalar mesons, which also melt earlier than the vector meson.

Is a charmed axial-vector meson already found

International Nuclear Information System (INIS)

Matsuda, S.

1976-12-01

A calculation is presented of the production rate via e + e - annihilation for a charmed p-wave meson of Jsup(P) = 1 + , based on a non-relativistic quark model of charmed hadrons. The results strongly suggest that the charmed axial-vector meson should be found copiously in association with a ground-state charmed meson. (author)

Distribution amplitudes of vector mesons

Energy Technology Data Exchange (ETDEWEB)

Braun, V.M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Broemmel, D. [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

2007-11-15

Results are presented for the lowest moment of the distribution amplitude for the K{sup *} vector meson. Both longitudinal and transverse moments are investigated. We use two flavours of O(a) improved Wilson fermions, together with a non-perturbative renormalisation of the matrix element. (orig.)

Unified chiral analysis of the vector meson spectrum from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Wes Armour; Chris Allton; Derek Leinweber; Anthony Thomas; Ross Young

2005-10-13

The chiral extrapolation of the vector meson mass calculated in partially-quenched lattice simulations is investigated. The leading one-loop corrections to the vector meson mass are derived for partially-quenched QCD. A large sample of lattice results from the CP-PACS Collaboration is analysed, with explicit corrections for finite lattice spacing artifacts. To incorporate the effect of the opening decay channel as the chiral limit is approached, the extrapolation is studied using a necessary phenomenological extension of chiral effective field theory. This chiral analysis also provides a quantitative estimate of the leading finite volume corrections. It is found that the discretisation, finite-volume and partial quenching effects can all be very well described in this framework, producing an extrapolated value of $M_\\rho$ in excellent agreement with experiment. This procedure is also compared with extrapolations based on polynomial forms, where the results are much less enlightening.

Spontaneous symmetry breaking and vector-meson dominance

International Nuclear Information System (INIS)

Caldi, D.G.; Pagels, H.

1977-01-01

This article is a continuation of our previous work on the rho-π puzzle. It examines further consequences of the unification of partial conservation of axial-vector current (PCAC) and vector-meson dominance (VMD) in which the pion is a Goldstone state and the rho is a ''dormant'' Goldstone state. Our new picture of the vector mesons does not require an A 1 meson although such a state is not ruled out. The Weinberg sum rules which provide the raison d'etre for the A 1 are reexamined. The first Weinberg sum rule can be accommodated without a narrow A 1 state although some enhancement seems required. Examining the J/sup P C/ = 1 +- nonet we conclude that a new state, the isoscalar octet partner of the B (1235) should exist around 1.7 GeV assuming ideal mixing. Without a detailed assumption on the mixing angle, its mass should be in the range 1.4 to 1.7 GeV. We also discuss the photon-rho interactions. In the standard VMD picture the predicted rate for rho → π + γ fails by five standard deviations, while in our picture this undesired result is averted

Quark-gluon plasma tomography by vector mesons

International Nuclear Information System (INIS)

Lovas, I.; Schram, Zs.; Csernai, L.P.; Hungarian Academy of Sciences, Budapest; Nyiri, A.

2001-01-01

The fireball formed in a heavy ion collision is characterized by the impact parameter vector b-vector, which can be determined from the multiplicity and the angular distribution of the reaction products. By appropriate rotations the b-vector vectors of each collision can be aligned into a fixed direction. Using the measured values of the momentum distributions independent integral equations can be formulated for the unknown emission densities (E M (r-vector)) and for the unknown absorption densities (Δμ(r-vector)) of the different vector mesons. (author)

Vector mesons and chiral symmetry

International Nuclear Information System (INIS)

Ecker, G.

1989-01-01

The ambiguities in the off-shell behaviour of spin-1 exchange can be resolved to O(p 4 ) in the chiral low-energy expansion if the asymptotic behaviour of QCD is properly incorporated. As a consequence, the chiral version of vector (and axial-vector) meson dominance is model independent. Additional high-energy constraints motivated by QCD determine the V,A resonance couplings uniquely. In particular, QCD in its effective chiral realization sucessfully predicts Γ(ρ→2π). 10 refs. (Author)

QCD sum-rules analysis of vector (1-) heavy quarkonium meson-hybrid mixing

Science.gov (United States)

Palameta, A.; Ho, J.; Harnett, D.; Steele, T. G.

2018-02-01

We use QCD Laplace sum rules to study meson-hybrid mixing in vector (1-) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four- and six-dimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multiresonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compared to single resonance models that include only the ground state, we find that models that also include excited states lead to significantly improved agreement between QCD and experiment. In the charmonium sector, we find that meson-hybrid mixing is consistent with a two-resonance model consisting of the J /ψ and a 4.3 GeV resonance. In the bottomonium sector, we find evidence for meson-hybrid mixing in the ϒ (1 S ) , ϒ (2 S ), ϒ (3 S ), and ϒ (4 S ).

Vector meson pair production in two-photon collisions at ARGUS

International Nuclear Information System (INIS)

Patel, P.M.

1989-01-01

New ARGUS results on exclusive final states produced in two-photon interactions are presented. Measurements of the vector meson pairs ρ + ρ - , ωρ 0 , ωω, K* + K* - and K* 0 bar K* 0 , as well as a search for φρ 0 , φω and φφ, are described. The results are compared with theoretical models. It is concluded that none of the models tells the full story when one considers the ARGUS data on all the possible vector meson pairs constructed from the 1 - vector nonet. 17 references, 5 figures, 1 table

Quantum chromodynamics with infinite number of vector mesons

International Nuclear Information System (INIS)

Geshkenbejn, B.V.

1988-01-01

Families of vector mesons Ρ,Ψ,Υ, contain an infinite number of resonances with gradually increasing widths are considered. The asymptotic freedom requirement involves a relationship between the electric width of k-th resonance and its mass M k derivative over the number k. It is shown that for the families of Ψ and Υ mesons the moment from experimental function R(s) is equal to the sum of the moment from a bare quark loop and the edge term which stems from replacing of summation by integration. These equalities are fulfilled up to 1% for 60 moments in the Ψ-meson family and up to 2% for 96 moments in the Υ-meson family. The electronic widths of the resonances and the Ρ-meson mass are calculated. 7 refs

Coherent vector-meson photoproduction with nuclear breakup in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Baltz, Anthony J.; Klein, Spencer R.; Nystrand, Joakim

2002-01-01

Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear interactions in a single collision are possible. In this Letter, we use mutual Coulomb excitation of both nuclei as a tag for moderate-impact-parameter collisions. We calculate the cross section for coherent vector-meson production accompanied by mutual excitation and show that the median impact parameter is much smaller than for untagged production. The vector-meson rapidity and transverse-momentum distribution are very different from untagged exclusive vector-meson production

From meson- and photon-nucleon scattering to vector mesons in nuclear matter

International Nuclear Information System (INIS)

Wolf, Gy.; Lutz, M.F.M.; Friman, B.

2003-01-01

A relativistic and unitary approach to pion- and photon-nucleon scattering taking into account the πN, ρN, ωN, ηN, πΔ, KΛ and KΣ channels is presented. The scheme dynamically generates the s- and d-wave baryon resonances N(1535), N(1650), N(1520) and N(1700) and as well as Δ(1620) and Δ(1700) in terms of quasi-local two-body interaction terms. A fair description of the experimental data relevant to the properties of slow vector mesons in nuclear matter is obtained. The resulting s-wave ρ- and ω-meson-nucleon scattering amplitudes which define the leading density modification of the ρ- and ω-meson spectral functions in nuclear matter are presented. (author)

Rho meson decay width in SU(2) gauge theories with 2 fundamental flavours

CERN Document Server

Janowski, Tadeusz; Pica, Claudio

2016-01-01

SU(2) gauge theories with two quark flavours in the fundamental representation are among the most promising theories of composite dynamics describing the electroweak sector. Three out of five Goldstone bosons in these models become the longitudinal components of the W and Z bosons giving them mass. Like in QCD, we expect a spectrum of excitations which appear as resonances in vector boson scattering, in particular the vector resonance corresponding to the rho-meson in QCD. In this talk I will present the preliminary results of the first calculation of the rho-meson decay width in this theory, which is analogous to rho to two pions decay calculation in QCD. The results presented were calculated in a moving frame with total momentum (0,0,1) on two ensembles. Future plans include using 3 moving frames on a larger set of ensembles to extract the resonance parameters more reliably and also take the chiral and continuum limits.

Holographic picture of heavy vector meson melting

Energy Technology Data Exchange (ETDEWEB)

Braga, Nelson R.F.; Diles, Saulo [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil); Martin Contreras, Miguel Angel [Universidad de los Andes, High Energy Group, Department of Physics, Bogota (Colombia)

2016-11-15

The fraction of heavy vector mesons produced in a heavy ion collision, as compared to a proton-proton collision, serves as an important indication of the formation of a thermal medium, the quark-gluon plasma. This sort of analysis strongly depends on understanding the thermal effects of a medium like the plasma on the states of heavy mesons. In particular, it is crucial to know the temperature ranges where they undergo a thermal dissociation, or melting. AdS/QCD models are know to provide an important tool for the calculation of hadronic masses, but in general are not consistent with the observation that decay constants of heavy vector mesons decrease with excitation level. It has recently been shown that this problem can be overcome using a soft wall background and introducing an extra energy parameter, through the calculation of correlation functions at a finite position of anti-de Sitter space. This approach leads to the evaluation of masses and decay constants of S wave quarkonium states with just one flavor dependent and one flavor independent parameter. Here we extend this more realistic model to finite temperatures and analyze the thermal behavior of the states 1S, 2S and 3S of bottomonium and charmonium. The corresponding spectral function exhibits a consistent picture for the melting of the states where, for each flavor, the higher excitations melt at lower temperatures. We estimate for these six states the energy ranges in which the heavy vector mesons undergo a transition from a well-defined peak in the spectral function to complete melting in the thermal medium. A very clear distinction between the heavy flavors emerges, with the bottomonium state Υ(1S) surviving a deconfinement transition at temperatures much larger than the critical deconfinement temperature of the medium. (orig.)

Vector mesons in strongly interacting matter

Indian Academy of Sciences (India)

Results on the light vector mesons ρ, , and , are summarized and compared. Almost all experiments report a softening of the spectral functions with increases in width depending on the density and temperature of the hadronic environment. No evidence for mass shifts is found in majority of the experiments. Remaining ...

Observation of a New Narrow Axial-Vector Meson alpha(1)(1420)

Czech Academy of Sciences Publication Activity Database

Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W.-C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d´Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Jörg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; 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.; Kremser, P.; Krinner, F.; 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.; Makins, N.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schmeing, S.; Schmidt, K.; Schlüter, T.; Selyunin, A.; Schmieden, H.; Schönning, K.; Schopferer, S.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

2015-01-01

Roč. 115, č. 8 (2015), 082001:1-6 ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * pion-nucleon scattering * hadron spectroscopy * light-meson spectrum * axial-vector mesons * exotic mesons Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.645, year: 2015

Electromagnetic properties and sizes of new vector mesons within the three-triplet model

International Nuclear Information System (INIS)

Govorkov, A.B.

1976-01-01

The new vector mesons psi(3095) and psi'(3684) are treated by analogy with the ω- and PHI-mesons, respectively, within the scheme of three triplets of the integer charge quarks-sakations. Their decay into the lepton pairs is calculated in the model of nonrelativistic harmonic oscillator. It appears that sizes of the new mesons decrease, and the effective mass of constituent quarks increases as compared with the corresponding quantities of the usual mesons. Within the vector meson dominence model the relation between the width of the transition psi → ν+γ and photoproduction cross section on nucleons is established and the estimate for the former is 3 keV

Vector mesons in dense matter and dilepton production in heavy ion collisions at intermediate energies

Energy Technology Data Exchange (ETDEWEB)

Santini, Elvira

2008-02-15

The vector meson spectral functions are calculated to the first order in the nuclear matter density assuming the dominant contribution comes from the couplings of the vector mesons to nucleons and nucleon resonances. An attempt is made to reproduce the HADES dilepton production data with the in-medium spectral functions of the vector mesons using the Relativistic Quantum Molecular Dynamics (RQMD) transport model developed earlier for modelling heavy-ion collisions. The results are sensitive to the in-medium broadening of nucleon resonances. A generally good agreement with the HADES data is achieved for selfconsistent treatment of the nucleon resonance broadening and the vector meson spectral functions. (orig.)

Vector mesons in dense matter and dilepton production in heavy ion collisions at intermediate energies

International Nuclear Information System (INIS)

Santini, Elvira

2008-01-01

The vector meson spectral functions are calculated to the first order in the nuclear matter density assuming the dominant contribution comes from the couplings of the vector mesons to nucleons and nucleon resonances. An attempt is made to reproduce the HADES dilepton production data with the in-medium spectral functions of the vector mesons using the Relativistic Quantum Molecular Dynamics (RQMD) transport model developed earlier for modelling heavy-ion collisions. The results are sensitive to the in-medium broadening of nucleon resonances. A generally good agreement with the HADES data is achieved for selfconsistent treatment of the nucleon resonance broadening and the vector meson spectral functions. (orig.)

Phases, quantum interferences and effective vector meson masses in nuclei

Energy Technology Data Exchange (ETDEWEB)

Soyeur, M.

1996-12-31

We discuss the prospects for observing the mass of {rho}- and {omega}-mesons around nuclear matter density by studying their coherent photoproduction in nuclear targets and subsequent in-medium decay into e{sup +}e{sup -}pairs. The quantum interference of {rho} and {omega}-mesons in the e{sup +}e{sup -}channel and the interference between Bethe-Heitler pairs and dielectrons from vector meson decays are of particular interest. (author). 21 refs.

The effect of vector meson decays on di-hadron fragmentation functions

International Nuclear Information System (INIS)

Matevosyan, H.H.; Thomas, A.W.; Bentz, W.

2014-01-01

Di-hadron Fragmentation Functions (DFF) provide a vast amount of information on the intricate details of the parton hadronization process. Moreover, they provide a unique access to the 'clean' extraction of nucleon transversity parton distribution functions in semi inclusive deep inelastic two hadron production process with a transversely polarised target. On the example of the u → π + π - we analyse the properties of unpolarized DFFs using their probabilistic interpretation. We use both the NJL-jet hadronization model and PYTHIA 8.1 event generator to explore the effect of the strong decays of the vector mesons produced in the quark hadronization process on the pseudoscalar DFFs. Our study shows that, even though it is less probable to produce vector mesons in the hadronization process than pseudo scalar mesons of the same charge, the products of their strong decays drastically affect the DFFs for pions because of the large combinatorial factors. Thus, an accurate description of both vector meson production and decays are crucial for theoretical understanding of DFFs. (authors)

Beauty vector meson decay constants from QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

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); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)

2016-01-22

We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

Photoproduction of vector mesons in proton-proton ultraperipheral collisions at the CERN Large Hadron Collider

Science.gov (United States)

Xie, Ya-Ping; Chen, Xurong

2018-05-01

Photoproduction of vector mesons is computed with dipole model in proton-proton ultraperipheral collisions (UPCs) at the CERN Large Hadron Collider (LHC). The dipole model framework is employed in the calculations of vector mesons production in diffractive processes. Parameters of the bCGC model are refitted with the latest inclusive deep inelastic scattering experimental data. Employing the bCGC model and boosted Gaussian light-cone wave function for vector mesons, we obtain the prediction of rapidity distributions of J/ψ and ψ(2s) mesons in proton-proton ultraperipheral collisions at the LHC. The predictions give a good description of the experimental data of LHCb. Predictions of ϕ and ω mesons are also evaluated in this paper.

Role of vector mesons in pion electroproduction

International Nuclear Information System (INIS)

Uleshchenko, V.V.

2007-01-01

The talk is concerned with mechanisms of pion production in deeply inelastic scattering related to the interaction of virtual photon with the nucleon via an intermediate vector-meson state of the probe. A clear evidence of these mechanisms in the HERMES experimental data is revealed

Calculation of excited vector meson electron widths using QCD sum rules

International Nuclear Information System (INIS)

Geshkenbein, B.V.

1984-01-01

The sum rules are suggested which allow one to calculate the electron widths of excited vector mesons of the PSI, UPSILON, rho meson family assuming the values of their masses to be known. The calculated values of the electron widths agree with experiment

Medium dependence of vector meson properties in heavy ion collisions

International Nuclear Information System (INIS)

Faessler, Amand; Fuchs, Christian

2007-01-01

Heavy ion collisions produce dense and hot nuclear matter. Dileptons give information about this hot and dense phase. The dileptons are produced by vector mesons. Theoretical calculation of dilepton production in the DLS (Berkeley), the HADES (GSI) experiments and the CERES, HELIOS and NA60 data from CERN give information about possible modifications of the vector meson properties in hot and dense nuclear matter. Here the description in relativistic quantum molecular dynamics of heavy ion collisions and dilepton production are presented and compared with data. (authors) Key words: heavy ion collisions; dense and hot nuclear matter; dileptons; medium dependence

The contribution of axial-vector mesons to hyperfine structure of muonic hydrogen

OpenAIRE

Dorokhov, A. E.; Kochelev, N. I.; Martynenko, A. P.; Martynenko, F. A.; Radzhabov, A. E.

2017-01-01

The contribution from the axial-vector meson exchange to the potential of the muon–proton interaction in muonic hydrogen induced by anomalous axial-vector meson coupling to two photon state is calculated. It is shown that such contribution to the hyperfine splitting in muonic hydrogen is large and important for a comparison with precise experimental data. In the light of our result, the proton radius “puzzle” is discussed.

Vector mesons in reactions with colliding electron-positron beams

International Nuclear Information System (INIS)

Rekalo, M.P.; Gakh, G.I.

1980-01-01

Polarization phenomena in the processes of vector meson production in reactions with colliding electron-positron beams e + e - → V+X, where V is a vector meson, X is a nondetected set of particles are investigated. For the one-photon mechanism of the process, where V and X are hadrons, the mutually unambiguous correspondence between the structural functions is found. The dependence of the e + e - → VX differential cross section upon the electron and positron polarizations is calculated using the virtual photon density matrix in the helicity basis. This formalism permits to take explicitly into account the P-invariance consequences for the angular distribution of the V-meson decay products. For the processes e + e - → πA 1 , and e + e - → rho + rho - the structural functions are calculated in terms of the corresponding electromagnetic form factors. It is noted that six functions out ten real structural functions describing the e + e - → VX reaction can be determined by means of investigation of the angular distribution of the V-meson decay products which is produced in collisions of unpolarized leptons. To study the collision of polarized leptons one more structural function can be determined. The formation of the X system with definite values of parity and spin is characterized by seven structural functions, five of which can be found while studying the angular distribution of the V-meson decay products produced in e + e - collisions with unpolarized (polarized) particles. If the spin of the X state is 1, in experiments with polarized beams all structural functions can be determined while investigating the angular distribution of the V-meson decay products

Vector meson decays in the chiral bag model

International Nuclear Information System (INIS)

Maxwell, O.V.; Jennings, B.K.

1985-01-01

Vector meson decays are examined in a model where a confined quark and antiquark annihilate, producing a pair of elementary pseudoscalar mesons. Two versions of the pseudoscalar meson-quark interaction are employed, one where the coupling is restricted to the bag surface and one where it extends throughout the bag volume. Energy conservation is ensured in the model through insertion of exponential factors containing the bag energy at each interaction vertex. To guarantee momentum conservation, a wave-packet description is utilized in which the decay widths are normalized by a factor involving the overlap of the initial bag state with the confined qanti q state of zero momentum. With either interaction, the model yields a value for the p-width that exceeds the empirical width by a factor two. For the Ksup(*) and PHI mesons, the computed widths depend strongly on the interaction employed. Implications of these results for chiral bag models are discussed. (orig.)

Spectroscopy of pseudoscalar and vector mesons and their electroweak decays

International Nuclear Information System (INIS)

Ablakulov, Kh.

1997-01-01

Proceeding from the effective action of QCD for bilocal meson fields the formula for the action describing the spectroscopy of mesons and their electroweak decays is obtained. The numerical solutions of the Salpeter equation (SE) for the qq-bound state and the Schwinger-Dyson equation (SDE) for the quark phase function are obtained with potential as sum of the oscillator and Coulomb terms. It is shown that for the oscillator potential and current quark mass m 0 0 → γγ) are 3-4 times smaller than their experimentations. This discrepancy was not removed even choosing other shapes of the potential. In order to resolve this problem the modification of the SDE, which consists in introducing the additional terms that do not change asymptotical properties of solutions of this equation is proposed. Using such modification both constant fπ and Γ(π 0 → γγ) are reproduced on a good quantitative level. The new SE for vector mesons is proposed and its solution with potential mentioned above gives the mass spectra of these mesons. Considering the τ → ρν decay the representation for leptonic decay constant of ρ meson f π , which expresses via solutions of the SDE and the proposed SE with a given potential is obtained. It is shown that the proposed SE allows to describe both the spectroscopy of vector mesons and their leptonic decay constants on a satisfactory level in comparison with the experimental values. (author)

Alternative space-time view of vector-meson dominance for virtual-photon--nucleus scattering

International Nuclear Information System (INIS)

Argyres, E.N.; Lam, C.S.

1977-01-01

We clarify the meaning of vector-meson dominance for virtual photons via a coupled-channel formalism, in which the photon can interact only by converting itself into a vector meson, the conversion occurring anywhere in space. We calculate the relative contributions of the different conversion regions, discuss their physical interpretation, and establish the equivalence of this approach to the usual treatment

Scattering of vector mesons off nucleons

International Nuclear Information System (INIS)

Lutz, M.F.M.; Friman, B.; Wolf, G.

2001-12-01

We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the πN, πΔ, ρN, ωN, ηN, K Λ, KΣ final states into account. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650) and N(1520) and isobar resonances Δ(1620) and δ(1700) in terms of quasi-local interaction vertices. The description of photon-induced processes is based on a generalized vector-meson dominance assumption which directly relates the electromagnetic quasi-local 4-point interaction vertices to the corresponding vertices involving the ρ and ω fields. We obtain a satisfactory description of the elastic and inelastic pion- and photon-nucleon scattering data in the channels considered. The resulting s-wave ρ- and ω-nucleon scattering amplitudes are presented. Using these amplitudes we compute the leading density modification of the ρ and ω mass distributions in nuclear matter. We find a repulsive mass shift for the ω meson at small nuclear density but predict considerable strength in resonance-hole like ω-meson modes. Compared to previous calculations our result for the ρ-meson spectral function shows a significantly smaller in-medium effect. This reflects a not too large coupling strength of the N(1520) resonance to the ρN channel. (orig.)

Heavy and Heavy-Light Mesons in the Covariant Spectator Theory

Science.gov (United States)

Stadler, Alfred; Leitão, Sofia; Peña, M. T.; Biernat, Elmar P.

2018-05-01

The masses and vertex functions of heavy and heavy-light mesons, described as quark-antiquark bound states, are calculated with the Covariant Spectator Theory (CST). We use a kernel with an adjustable mixture of Lorentz scalar, pseudoscalar, and vector linear confining interaction, together with a one-gluon-exchange kernel. A series of fits to the heavy and heavy-light meson spectrum were calculated, and we discuss what conclusions can be drawn from it, especially about the Lorentz structure of the kernel. We also apply the Brodsky-Huang-Lepage prescription to express the CST wave functions for heavy quarkonia in terms of light-front variables. They agree remarkably well with light-front wave functions obtained in the Hamiltonian basis light-front quantization approach, even in excited states.

Leptonic decay of light vector mesons in an independent quark model

International Nuclear Information System (INIS)

Barik, N.; Dash, P.C.; Panda, A.R.

1993-01-01

Leptonic decay widths of light vector mesons are calculated in a framework based on the independent quark model with a scalar-vector harmonic potential. Assuming a strong correlation to exist between the quark-antiquark momenta inside the meson, so as to make their total momentum identically zero in the center-of-mass frame of the meson, we extract the quark and antiquark momentum distribution amplitudes from the bound quark eigenmode. Using the model parameters determined from earlier studies, we arrive at the leptonic decay widths of (ρ,ω,φ) as (6.26 keV, 0.67 keV, 1.58 keV) which are in very good agreement with the respective experimental data (6.77±0.32 keV, 0.6±0.02 keV, 1.37±0.05 keV)

Inclusive vector meson production and hadron structure

International Nuclear Information System (INIS)

Boeckmann, K.

1977-08-01

It is shown that J/PSI production in hadronic interactions is dominated by central production from sea quarks even at beam momenta as low as 40 GeV/c. All known experimental data on inclusive vector meson production support the hypothesis that cross sections obtained from meson-nucleon and nucleon-nucleon interactions have to be compared in the quark C.M. system. With the distinction of sea quark and valence quark interactions in the additive quark model a consistent description of inclusive rho, K*, PHI and J/PSI production in hadronic interactions. A natural connection of inclusive rho 0 production cross sections in anti pp, pp and πp interactions is obtained. (orig.) [de

Masses of scalar and axial-vector B mesons revisited

Energy Technology Data Exchange (ETDEWEB)

Cheng, Hai-Yang [Academia Sinica, Institute of Physics, Taipei (China); Yu, Fu-Sheng [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

2017-10-15

The SU(3) quark model encounters a great challenge in describing even-parity mesons. Specifically, the q anti q quark model has difficulties in understanding the light scalar mesons below 1 GeV, scalar and axial-vector charmed mesons and 1{sup +} charmonium-like state X(3872). A common wisdom for the resolution of these difficulties lies on the coupled channel effects which will distort the quark model calculations. In this work, we focus on the near mass degeneracy of scalar charmed mesons, D{sub s0}{sup *} and D{sub 0}{sup *0}, and its implications. Within the framework of heavy meson chiral perturbation theory, we show that near degeneracy can be qualitatively understood as a consequence of self-energy effects due to strong coupled channels. Quantitatively, the closeness of D{sub s0}{sup *} and D{sub 0}{sup *0} masses can be implemented by adjusting two relevant strong couplings and the renormalization scale appearing in the loop diagram. Then this in turn implies the mass similarity of B{sub s0}{sup *} and B{sub 0}{sup *0} mesons. The P{sub 0}{sup *}P{sub 1}{sup '} interaction with the Goldstone boson is crucial for understanding the phenomenon of near degeneracy. Based on heavy quark symmetry in conjunction with corrections from QCD and 1/m{sub Q} effects, we obtain the masses of B{sup *}{sub (s)0} and B{sup '}{sub (s)1} mesons, for example, M{sub B{sub s{sub 0{sup *}}}} = (5715 ± 1) MeV + δΔ{sub S}, M{sub B}{sup {sub '{sub s{sub 1}}}} = (5763 ± 1) MeV + δΔ{sub S} with δΔ{sub S} being 1/m{sub Q} corrections. We find that the predicted mass difference of 48 MeV between B{sup '}{sub s1} and B{sub s0}{sup *} is larger than that of 20-30 MeV inferred from the relativistic quark models, whereas the difference of 15 MeV between the central values of M{sub B}{sup {sub '{sub s{sub 1}}}} and M{sub B}{sup {sub '{sub 1}}} is much smaller than the quark model expectation of 60-100 MeV. Experimentally, it is important to have a precise

Exclusive vector meson production at HERA

International Nuclear Information System (INIS)

Szuba, Dorota

2013-01-01

The exclusive photoproduction of Υ has been studied with the ZEUS detector in ep collisions at HERA. The exponential slope, b, of the |t|-dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured. This constitutes the first measurement of the |t|-dependence of the γp→Υp cross section. The differential crosssections as a function of t at lower energies of γp centre-of-mass has been studied in exclusive diffractive photoproduction of J/ψ mesons with the H1 detector. The exclusive electroproduction of two pions has been measured by the ZEUS experiment. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, assuming that the studied mass range includes the contributions of the ρ, ρ′ and . ρ'' vector-meson states.

Fock exchange in meson theories of nuclei

International Nuclear Information System (INIS)

Bolsterli, M.

1986-01-01

The Fock exchange term in meson field theories of nuclear systems is shown to arise from a two-loop ground-state self-energy diagram. Evaluation of this diagram gives the relativistic or semirelativistic analog of the Fock exchange energy; it differs from the nucleon-nucleon Fock energy in including retardation effects. In finite meson-field theories of nuclear systems, the variational nature of the meson-field analog of the Hartree-Fock energy functional can be further elucidated. 4 refs

Spectrum-generating SU(4) in particle physics. II. Electromagnetic decays of vector mesons

International Nuclear Information System (INIS)

Bohm, A.; Teese, R.B.

1977-09-01

The decay rates for the electromagnetic decays of vector mesons are derived within the spectrum-generating SU(4) approach. Radiative as well as leptonic decays of vector mesons can be derived from one theoretical assumption and given in terms of three reduced matrix elements. The implication of the experimental value GAMMA(rho → πγ) = (35 +- 10) keV for the form of the electromagnetic current operator is discussed

Why do nucleons cling. [Meson theory

Energy Technology Data Exchange (ETDEWEB)

Kumar, N [Hindu Coll., Delhi (India)

1976-10-01

The nature of the forces which bind nucleons together within the nucleus of an atom have been discussed in detail. The characteristic properties of the nucleons, such as spin, interaction range etc. and the meson theory of nuclear forces are described. The present researches indicate that the force between two nucleons in a many-nucleon system is not very different from the force between two free nucleons. Researches related to the origin of nuclear forces based on the meson theory are now mainly concerned with the role played by the heavier mesons and the two pion exchanges in the middle region around 0.7 fm. (10/sup -13/ cm).

Vector meson production in the dimuon channel in the ALICE experiment at the LHC

CERN Document Server

Massacrier, L.

2011-01-01

The purpose of the ALICE experiment at the LHC is the study of the Quark Gluon Plasma (QGP) formed in ultra-relativistic heavy-ion collisions, a state of matter in which quarks and gluons are deconfined. The properties of this state of strongly-interacting matter can be accessed through the study of light vector mesons ($\\rho$, $\\omega$ and $\\phi$). Indeed, the strange quark content ($s\\bar{s}$) of the $\\phi$ meson makes its study interesting in connection with the strangeness enhancement observed in heavy-ion collisions. Moreover, $\\rho$ and $\\omega$ spectral function studies give information on chiral symmetry restoration. Vector meson production in pp collisions is important as a baseline for heavy-ion studies and for constraining hadronic models. We present results on light vector meson production obtained with the muon spectrometer of the ALICE experiment in pp collisions at $\\sqrt{s}$=7 TeV. Production ratios, integrated and differential cross sections for $\\phi$ and $\\omega$ are presented. Those result...

Production of polarized vector mesons off nuclei

International Nuclear Information System (INIS)

Kopeliovich, B. Z.; Nemchik, J.; Schmidt, Ivan

2007-01-01

Using the light-cone QCD dipole formalism we investigate manifestations of color transparency (CT) and coherence length (CL) effects in electroproduction of longitudinally (L) and transversally (T) polarized vector mesons. Motivated by forthcoming data from the HERMES experiment we predict both the A and Q 2 dependence of the L/T ratios for ρ 0 mesons produced coherently and incoherently off nuclei. For an incoherent reaction the CT and CL effects add up and result in a monotonic A dependence of the L/T ratio at different values of Q 2 . In contrast, for a coherent process the contraction of the CL with Q 2 causes an effect opposite to that of CT and we expect quite a nontrivial A dependence

Exclusive vector meson production at HERA

Energy Technology Data Exchange (ETDEWEB)

Szuba, Dorota [Hamburg University, Hamburg (Germany); Collaboration: H1 Collaboration; ZEUS Collaboration

2013-04-15

The exclusive photoproduction of {Upsilon} has been studied with the ZEUS detector in ep collisions at HERA. The exponential slope, b, of the |t|-dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured. This constitutes the first measurement of the |t|-dependence of the {gamma}p{yields}{Upsilon}p cross section. The differential crosssections as a function of t at lower energies of {gamma}p centre-of-mass has been studied in exclusive diffractive photoproduction of J/{psi} mesons with the H1 detector. The exclusive electroproduction of two pions has been measured by the ZEUS experiment. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, assuming that the studied mass range includes the contributions of the {rho}, {rho} Prime and . {rho}'' vector-meson states.

On the Reduction of Vector and Axial-Vector Fields in a Meson Effective Action at O(p4)

International Nuclear Information System (INIS)

Bel'kov, A.A.; Lanev, A.V.; Schaale, A.

1994-01-01

Starting from an effective NJL-type quark interaction we have derived an effective meson action for the pseudoscalar sector. The vector and axial-vector degrees of freedom have been integrated out, applying the static equations of motion. As the results we have found a (reduced) pseudoscalar meson Lagrangian of the Gasser-Leutwyler type with modified structure coefficients L i . This method has been also used to construct the reduced weak and electromagnetic-weak currents. The application of the reduced Lagrangian and currents has been considered in physical processes. 36 refs., 1 fig., 1 tab

Relativistic bound states: a mass formula for vector mesons

International Nuclear Information System (INIS)

Richard, J.L.; Sorba, P.

1975-07-01

In the framework of a relativistic description of two particles bound states, a mass formula for vector mesons considered as quark-antiquark systems bound by harmonic oscillator like forces is proposed. Results in good agreement with experimental values are obtained [fr

Light vector meson production at the LHC with the ALICE detector

CERN Document Server

Incani, Elisa

2013-01-01

The measurement of light vector meson production (\\rho, \\omega, \\phi) in pp collisions provides insight into soft Quantum Chromodynamics (QCD) processes in the LHC energy range. Calculations in this regime are based on QCD inspired phenomenological models that must be tuned to the data. Moreover, light vector meson production provides a reference for high-energy heavy-ion collisions. A measurement of the \\phi and \\omega differential cross sections as performed by the ALICE experiment in pp collisions at 7 TeV and of the \\phi cross section in pp collisions at 2.76 TeV through their decay to muon pairs and in the rapidity interval 2.5 < y < 4.

Vector Mesons in Cold Nuclear Matter

International Nuclear Information System (INIS)

Rodrigues, Tulio E; Arruda-Neto, Joāo Dias de Toledo

2013-01-01

The attenuation of vector mesons in cold nuclear matter is studied through the mechanism of incoherent photoproduction off complex nuclei. The latter is described via the time-dependent multi-collisional Monte Carlo (MCMC) intranuclear cascade model. The results for the transparency ratios of ω mesons reproduce previous measurements of CB-ELSA/TAPS with an inelastic ωN cross section around 40 mb for ρ ω ∼ 1.1 GeV/c. The corresponding in-medium width (nuclear rest frame) is extracted dinamically from the algorithm and depends on the average nuclear density p N and target nucleus: ∼ 49.2 MeV/c 2 for carbon (p N ≈ 0.114 far −3 ) and ∼ 77.3 MeV/c 2 for lead (p N ≈ 0.137 far −−3 ). The calculations fail to reproduce the huge absorption observed at JLab assuming the same inelastic cross section and the discrepancy between the two experiments remains a challenge.

Perspectives of Scalar- and Vector- Meson Production in Hadron-Nucleus Reactions

International Nuclear Information System (INIS)

Cassing, W.

2000-01-01

The production and decay of vector mesons (ρ, ω) in pA reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium decays like π + π - or π 0 γ might provide complementary information to their dilepton (e + e - ) decays. Whereas the π + π - signal from the ρ-meson is found to be strongly distorted by pion rescattering, the ω- meson Dalitz decay to π 0 γ appears promising even for more heavy nuclei. The perspectives of scalar meson ( f 0 , a 0 ) production in pp reactions are investigated within a boson-exchange model indicating that the f 0 -meson might hardly be detected in these collisions in the K(anti)K or ππ decay channels whereas the exclusive channel pp→da 0 + looks very promising. (author)

Hadronic slopes and cross-sections for vector mesons

International Nuclear Information System (INIS)

Ferreira, Erasmo; Pereira, Flavio

1998-01-01

The data on photoproduction of vector mesons at high energies shows that the correlation between observables and their dependence on the energy and on the hadronic sizes which is characteristics of nonperturbative dynamics also appear in these processes. The analysis of the data exhibits effects of the interplay between perturbative and nonperturbative contributions. (author)

Exclusive central diffractive production of scalar, pseudoscalar and vector mesons

Directory of Open Access Journals (Sweden)

Lebiedowicz P.

2014-01-01

Full Text Available We discuss exclusive central diffractive production of scalar (ƒ0(980, ƒ0(1370, ƒ0(1500, pseudoscalar (η, η′(958, and vector (ρ0 mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the ƒ0(980 and η production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the ρ0 production the photon-pomeron and pomeron-photon exchanges are considered. The coupling parameters of tensor pomeron and/or reggeon are fixed from the H1 and ZEUS experimental data of the γp → ρ0 p reaction. We present first predictions of this mechanism for pp → ppπ+π− reaction being studied at COMPASS, RHIC, Tevatron, and LHC. Correlation in azimuthal angle between outgoing protons and distribution in pion rapidities at √s = 7 TeV are presented. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron.

Confined quarks and the decays of ''old'' and ''new'' vector and tensor mesons

International Nuclear Information System (INIS)

Montvay, I.; Spitzer, J.

1977-06-01

The two-body strong decays of the vector and tensor mesons were calculated from the quark 100p coupling graph. The main assumptions of the model were: (i) confinement in the Minkowski-space of relative positions (and momenta); (ii) an effective quark mass approximation for quark propagation inside hadrons; and (iii) the quark diagram structure of hadrons interactions. In the calculations oscillator type (Gaussian) wave functions were used. The description of the decays of ''old'' (non-charmed) vector and tensor mesons leads to a consistent qualitative picture with small effective masses (about 300 MeV) and considerable differences in the size of the quark confinement region for different mesons. The ''new'' (charmed) particle decays and, therefore, the SU(3)-breaking were also considered. (Sz.N.Z.)

Dilepton and vector meson production in heavy-ion reactions

International Nuclear Information System (INIS)

Wolf, Gy.

1997-01-01

A nonperturbative dynamical study of dilepton an vector meson production in heavy-ion collisions from 1 to 2 GeV/A bombarding energies is presented incorporating all known sources relevant in this energy range. The dynamical evolution of the nucleus-nucleus collision is described by a transport equation of the Boltzmann-Uehling-Uhlenbeck type evolving phase-space distribution functions for nucleons, baryon resonances, pions, η's, ρ's and σ's with their isospin degrees of freedom. In particular, the sensitivity of the calculated yields to predicted changes of the ρ and ω mesons in dense matter is investigated. (author)

On the inclusive reaction e+e- → VX with regard for polarization states of generated vector meson

International Nuclear Information System (INIS)

Khachtryan, G.N.; Shakhnazaryan, Yu.G.

1977-01-01

The e + e - →VX inclusive process has been considered with allowance made for polarization states of a vector meson. The tensor that describes the vortex of the γ→VX transition has also been considered. In the general case the tensor contains eight structural functions. The elements of the vector meson density matrix have been calculated in the spiral representation. These elements are expressed in terms of the given structural functions and polarization vectors of annihilating particles. It is shown that the structural functions can be determined from the study of angular distribution of products of the meson vector decay on pseudoscalar particles (p→2π, ω→3π, phi→2K) and on a lepton-antilepton pair (PSI, PSI'→e + e - )

Effective meson lagrangian with chiral and heavy quark symmetries from quark flavor dynamics

International Nuclear Information System (INIS)

Ebert, D.; Feldmann, T.; Friedrich, R.; Reinhardt, H.

1994-06-01

By bosonization of an extended NJL model we derive an effective meson theory which describes the interplay between chiral symmetry and heavy quark dynamics. This effective theory is worked out in the low-energy regime using the gradient expansion. The resulting effective lagrangian describes strong and weak interactions of heavy B and D mesons with pseudoscalar Goldstone bosons and light vector and axial-vector mesons. Heavy meson weak decay constants, coupling constants and the Isgur-Wise function are predicted in terms of the model parameters partially fixed from the light quark sector. Explicit SU(3) F symmetry breaking effects are estimated and, if possible, confronted with experiment. (orig.)

Production ratio of pseudoscalar to vector mesons

International Nuclear Information System (INIS)

Chliapnikov, P.V.; Uvarov, V.A.

1990-01-01

The P/V ratio of directly produced pseudoscalar (P) to vector (V) mesons is analysed using the data on the K S 0 and K * (892) total inclusive cross sections in pp, π + p and K ± p reactions. The indication for a change of P/V from a value of about 1 at low energies, where the fragmentation processes dominate, to a value of 1/3, suggested by spin-statistics, at high energies is discussed. (orig.)

Search for modification of vector meson properties in nuclei

International Nuclear Information System (INIS)

Clarisse Tur

2005-01-01

QCD sum rules depict the atomic nucleus as being a medium with partially restored chiral symmetry. This property of the nucleus would imply that the properties of vector mesons, such as their mass and width, are modified when produced in the nuclear medium, since they are controlled by chiral symmetry and its spontaneous as well as explicit breaking in QCD. The g7 (or E01-112) experiment was therefore designed to look for medium effects on the properties of the light vector mesons (rho, omega, and phi) in photoproduction, through their rare leptonic decay into e+e-. This decay channel has been preferred to the two pion channel to avoid distorting the information by strong final interactions. The data for this experiment was taken in the fall of 2002 using the CLAS detector at the Jefferson Laboratory. A bremsstrahlung photon beam was sent on a target containing a liquid deuterium cell and several nuclear targets: C, Fe, Ti, and Pb. Remarkably clean e + e - invariant mass spectra were obtained thanks to the outstanding pion rejection with CLAS and its excellent mass resolution. They represent the first observation of the photoproduction of the rho, omega and phi mesons close to threshold via their rare decay into e+e-. A depletion of the omega and phi peaks was observed with increasing target density. This depletion was not seen as markedly in the simulations done using a code based on the BUU transport equations. The data was broken up per target and fitted using the unmodified rho, omega and phi invariant mass distributions from the BUU simulation code. The Dalitz decay contribution of the omega obtained with the same code as well as the combinatorial background shape from mixed e+e- events were also included in the fit. The overall quality of the fits is suggestive of no medium effects observed on the properties of the vector mesons from this data set. However the contribution from the Bethe-Heitler has to be fully understood and incorporated in the fits before a

Vector manifestation and violation of vector dominance in hot matter

International Nuclear Information System (INIS)

Harada, Masayasu; Sasaki, Chihiro

2004-01-01

We show the details of the calculation of the hadronic thermal corrections to the two-point functions in the effective field theory of QCD for pions and vector mesons based on the hidden local symmetry (HLS) in hot matter using the background field gauge. We study the temperature dependence of the pion velocity in the low-temperature region determined from the hadronic thermal corrections, and show that, due to the presence of the dynamical vector meson, the pion velocity is smaller than the speed of the light already at one-loop level, in contrast to the result obtained in the ordinary chiral perturbation theory including only the pion at one-loop. Including the intrinsic temperature dependences of the parameters of the HLS Lagrangian determined from the underlying QCD through the Wilsonian matching, we show how the vector manifestation (VM), in which the massless vector meson becomes the chiral partner of pion, is realized at the critical temperature. We present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion: we find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analyses on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson

Mesonic spectroscopy of Minimal Walking Technicolor

DEFF Research Database (Denmark)

Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino

2010-01-01

We investigate the structure and the novel emerging features of the mesonic non-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD...

Results and future prospects of exclusive vector meson production with pPb collisions at CMS

CERN Document Server

Chudasama, Ruchi

2017-01-01

Exclusive photoproduction of vector mesons (Upsilon and Rho0) is studied with the large photon flux available in ultra-peripheral pPb collisions at sqrt(sNN) =5.02 TeV with CMS experiment. It provides a clean probe of the gluon distribution at small values of parton fractional momenta $x$ at centralrapidities ($y < 2.5$). The cross sections are measured as a function of the photon-proton centre-of-mass energy, extending the energy range explored by H1 and ZEUS Experiments at HERA. In addition, the differential cross sections (dsigma/dt), where $\\abs{t} \\approx p^2_T$ is the squared transverse momentum of produced vector mesons, are measured and the slope parameters are obtained. The results are compared to previous measurements and to theoretical predictions. Finally, prospect for further measurements of vector meson production that can be performed using the 2016 pPb collision data at 8 TeV to be collected at the end of the year are presented.

Dilepton Yields from Brown-Rho Scaled Vector Mesons Including Memory Effects

International Nuclear Information System (INIS)

Schenke, Bjoern; Greiner, Carsten

2007-01-01

Scenarios with dropping vector meson masses, motivated by the work of Brown and Rho, have been strongly discussed after recent NA60 Collaboration data were presented. In this Letter they are investigated within a nonequilibrium field theoretical description that includes quantum mechanical memory. Dimuon yields are calculated by application of a model for the fireball, and strong modifications are found in the comparison to quasiequilibrium calculations, which assume instantaneous adjustment of all meson properties to the surrounding medium. In addition, results for the situation of very broad excitations are presented

The contribution of pseudoscalar and axial-vector mesons to hyperfine structure of muonic hydrogen

OpenAIRE

Dorokhov, A. E.; Kochelev, N. I.; Martynenko, A. P.; Martynenko, F. A.; Radzhabov, A. E.; Faustov, R. N.

2017-01-01

In the framework of the quasipotential method in quantum electrodynamics we calculate the contribution of light pseudoscalar (PS) and axial-vector (AV) mesons to the interaction operator of a muon and a proton in muonic hydrogen atom. The coupling of mesons with the muon is via two-photon intermediate state. The parametrization of the transition form factor of two photons into PS and AV mesons, based on the experimental data on the transition form factors and QCD asymptotics, is used. Numeric...

Numerical solution of integral equations, describing mass spectrum of vector mesons

International Nuclear Information System (INIS)

Zhidkov, E.P.; Nikonov, E.G.; Sidorov, A.V.; Skachkov, N.B.; Khoromskij, B.N.

1988-01-01

The description of the numerical algorithm for solving quasipotential integral equation in impulse space is presented. The results of numerical computations of the vector meson mass spectrum and the leptonic decay width are given in comparison with the experimental data

Discovery of massive neutral vector mesons

International Nuclear Information System (INIS)

Anon.

1976-01-01

Personal accounts of the discovery of massive neutral vector mesons (psi particles) are given by researchers S. Ting, G. Goldhaber, and B. Richter. The double-arm spectrometer and the Cherenkov effect are explained in a technical note, and the solenoidal magnetic detector is discussed in an explanatory note for nonspecialists. Reprints of three papers in Physical Review Letters which announced the discovery of the particles are given: Experimental observation of a heavy particle J, Discovery of a narrow resonance in e + e - annihilation, and Discovery of a second narrow resonance in e + e - annihilation. A discussion of subsequent developments and scientific biographies of the three authors are also presented. 25 figures

Off-diagonal helicity density matrix elements for vector mesons produced at LEP

International Nuclear Information System (INIS)

Anselmino, M.; Bertini, M.; Quintairos, P.

1997-05-01

Final state q q-bar interactions may give origin to non zero values of the off-diagonal element ρ 1 of the helicity density matrix of vector mesons produced in e + e - annihilations, as confirmed by recent OPAL data on φ and D * 's. Predictions are given for ρ1,-1 of several mesons produced at large z and small PT, collinear with the parent jet; the values obtained for θ and D * are in agreement with data. (author)

Structure of exotic nuclei and superheavy elements in meson field theory

Energy Technology Data Exchange (ETDEWEB)

Linn, Khin Nyan

2008-07-15

In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)

Structure of exotic nuclei and superheavy elements in meson field theory

International Nuclear Information System (INIS)

Linn, Khin Nyan

2008-07-01

In this work the nuclear structure of exotic nuclei and superheavy nuclei is studied in a relativistic framework. In the relativistic mean-field (RMF) approximation, the nucleons interact with each other through the exchange of various effective mesons (scalar, vector, isovector-vector). Ground state properties of exotic nuclei and superheavy nuclei are studied in the RMF theory with the three different parameter sets (ChiM,NL3,NL-Z2). Axial deformation of nuclei within two drip lines are performed with the parameter set (ChiM). The position of drip lines are investigated with three different parameter sets (ChiM,NL3,NL-Z2) and compared with the experimental drip line nuclei. In addition, the structure of hypernuclei are studied and for a certain isotope, hyperon halo nucleus is predicted. (orig.)

In-medium behaviour of vector mesons and the longitudinal and transverse response functions in (e,e'p) reactions

International Nuclear Information System (INIS)

Soyeur, M.; Brown, G.E.; Rho, M.

1991-01-01

The electromagnetic form factors of nucleons appear dominated by vector mesons at momentum transfers small than ∼ 1 GeV/c. It is therefore expected that measurements of quantities involving the electromagnetic form factors of nucleons embedded in nuclei will be sensitive to changes in vector meson properties arising from their interaction with the medium. Longitudinal and transverse response functions measured in quasi-elastic (e,e'p) reactions provide such data for two very different operators, the charge and the current densities. We show that a decrease of vector meson masses in the medium, consistent with present expectations about chiral symmetry restoration in nuclei, produces the quenching observed in the longitudinal response of light systems ( 3 He, 4 He) and part of this quenching for heavier nuclei 40 Ca where nuclear correlations are expected to generate an additional suppression of the longitudinal response. The transverse response is almost unchanged, in agreement with the data. Difficulties in extrating very quantitative information on the in-medium behaviour of vector mesons from (e,e'p) data are pointed out

Exclusive photoproduction of vector mesons in proton-lead ultraperipheral collisions at the LHC

Science.gov (United States)

Xie, Ya-Ping; Chen, Xurong

2018-02-01

Rapidity distributions of vector mesons are computed in dipole model proton-lead ultraperipheral collisions (UPCs) at the CERN Larger Hadron Collider (LHC). The dipole model framework is implemented in the calculations of cross sections in the photon-hadron interaction. The bCGC model and Boosted Gaussian wave functions are employed in the scattering amplitude. We obtain predictions of rapidity distributions of J / ψ meson proton-lead ultraperipheral collisions. The predictions give a good description to the experimental data of ALICE. The rapidity distributions of ϕ, ω and ψ (2 s) mesons in proton-lead ultraperipheral collisions are also presented in this paper.

Transverse Momentum Distribution of Vector Mesons Produced in Ultraperipheral Relativistic Heavy Ion Collisions

International Nuclear Information System (INIS)

Hencken, Kai; Baur, Gerhard; Trautmann, Dirk

2006-01-01

We study the transverse momentum distribution of vector mesons produced in ultraperipheral relativistic heavy ion collisions (UPCs). In UPCs there is no strong interaction between the nuclei, and the vector mesons are produced in photon-nucleus collisions where the (quasireal) photon is emitted from the other nucleus. Exchanging the role of both ions leads to interference effects. A detailed study of the transverse momentum distribution, which is determined by the transverse momentum of the emitted photon, the production process on the target, and the interference effect, is done. We study the unrestricted cross section and the one with an additional electromagnetic excitation of one or both ions; in the latter case small impact parameters are emphasized

Measuring nuclear transparency from exclusive vector meson production in lepton-nucleus scattering

International Nuclear Information System (INIS)

Fang, G.Y.

1994-01-01

Preliminary results on the measurement of nuclear transparencies from exclusive ρ 0 meson production from E665 at Fermilab are reported. The data were collected on hydrogen, deuterium, carbon, calcium, and lead targets with a mean beam energy of 470 GeV. Increases in the transparencies are observed in both coherent and incoherent production channels as the virtuality of the photon increases, as expected of color transparency. Ideas of systematic studies of color transparency in exclusive vector meson production at CEBAF are discussed

Unitary unified field theories

International Nuclear Information System (INIS)

Sudarshan, E.C.G.

1976-01-01

This is an informal exposition of some recent developments. Starting with an examination of the universality of electromagnetic and weak interactions, the attempts at their unification are outlined. The theory of unitary renormalizable self-coupled vector mesons with dynamical sources is formulated for a general group. With masses introduced as variable parameters it is shown that the theory so defined is indeed unitary. Diagrammatic rules are developed in terms of a chosen set of fictitious particles. A number of special examples are outlined including a theory with strongly interacting vector and axial vector mesons and weak mesons. Applications to weak interactions of strange particles is briefly outlined. (Auth.)

Measuring nuclear transparency from exclusive vector meson production in lepton-nucleus scattering

Energy Technology Data Exchange (ETDEWEB)

Fang, G.Y. [Harvard Univ., Cambridge, MA (United States)

1994-04-01

Preliminary results on the measurement of nuclear transparencies from exclusive {rho}{sup 0} meson production from E665 at Fermilab are reported. The data were collected on hydrogen, deuterium, carbon, calcium, and lead targets with a mean beam energy of 470 GeV. Increases in the transparencies are observed in both coherent and incoherent production channels as the virtuality of the photon increases, as expected of color transparency. Ideas of systematic studies of color transparency in exclusive vector meson production at CEBAF are discussed.

Quark-gluon plasma tomography by vector mesons

International Nuclear Information System (INIS)

Lovas, I.

2001-01-01

Full text: The most important aim of relativistic heavy ion experiments is the observation f the quark-gluon plasma formation. In order to detect the transition into the plasma state it is desirable to map the density profile of the fireball formed in the collision. Here we investigate the possibility of this mapping by tomography. The fireball is characterized by the impact parameter vector b, which can be determined from the multiplicity and the angular distribution of the reaction products. By appropriate rotations the b vectors of each collision can be aligned into a fixed direction. Using the measured values of the momentum distributions independent integral equations can be formulated for the unknown emission densities (EM(r) and for the unknown absorption densities (Δ μ M (r)) of the different vector mesons M(≡ ω 0 , ρ 0 , φ 0 , ψ 0 , ψ 0' , Υ). At a fixed value of M and b the number of detected mesons N M (p,b) with momentum p, can be expressed by the following formula: N M (p,b) = ∫ V(b) dr EM(r) exp[-μ M (p)L(r,p o )] V(b) R(r, po)] exp[- ∫ from r until R(r,p 0 ) dl ' Δ μ M (r ' ,p)], where the average value of the absorption coefficient having no r dependence is denoted by μ(p), while Δ μM is defined as Δ μM = μ M - μ- M . The meson arrives to the surface of the fireball at R(r, p 0 ). The length of the path between r and R is denoted by L(r, po). The equation given above can be considered as an integral equation. Unfortunately it can not be transformed into an exact system of linear equations. However an iterative procedure can be constructed in such a way that in every iterative step a linear system of equations must be solved. N M (p,b) = ∫ V(b) dr exp[- μ M (p) L(r,p o )] [E M n (r) Σ from k=O until (n-1) (1/k !) (- ∫ from r until R (r, p 0 ) dl ' Δ μM n-1 (r ' , p) k + E M n-1 (r) (1/n !) (- ∫ from r until R(r, p 0 ) dl ' Δ μM n-1 (r ' , p)) (n-1) (- ∫ from r until R(r, p 0 ) dl ' Δ μM (n) (r ' , p))]. Since

Covariant Spectator Theory of heavy–light and heavy mesons and the predictive power of covariant interaction kernels

Energy Technology Data Exchange (ETDEWEB)

Leitão, Sofia, E-mail: sofia.leitao@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Stadler, Alfred, E-mail: stadler@uevora.pt [Departamento de Física, Universidade de Évora, 7000-671 Évora (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Peña, M.T., E-mail: teresa.pena@tecnico.ulisboa.pt [Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Biernat, Elmar P., E-mail: elmar.biernat@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2017-01-10

The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy–light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin–orbit and tensor forces and do not allow to separate the spin–spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark–antiquark interactions.

Quantum field theory approaches to meson structure

International Nuclear Information System (INIS)

Branz, Tanja

2011-01-01

Meson spectroscopy became one of the most interesting topics in particle physics in the last ten years. In particular, the discovery of new unexpected states in the charmonium spectrum which cannot be simply explained by the constituent quark model attracted the interest of many theoretical efforts. In the present thesis we discuss different meson structures ranging from light and heavy quark-antiquark states to bound states of hadrons-hadronic molecules. Here we consider the light scalar mesons f 0 (980) and a 0 (980) and the charmonium-like Y(3940), Y(4140) and Z ± (4430) states. In the discussion of the meson properties like mass spectrum, total and partial decay widths and production rates we introduce three different theoretical methods for the treatment and description of hadronic structure. For the study of bound states of mesons we apply a coupled channel approach which allows for the dynamical generation of meson-meson resonances. The decay properties of meson molecules are further on studied within a second model based on effective Lagrangians describing the interaction of the bound state and its constituents. Besides hadronic molecules the effective Lagrangian approach is also used to study the radiative and strong decay properties of ordinary quark-antiquark (q anti q) states. The AdS/QCD model forms the completion of the three theoretical methods introduced in the present thesis. This holographic model provides a completely different ansatz and is based on extra dimensions and string theory. Within this framework we calculate the mass spectrum of light and heavy mesons and their decay constants.

Meson photoproduction (CLAS)

Energy Technology Data Exchange (ETDEWEB)

Steffen Strauch

2009-10-01

This is a brief and selective discussion of meson photoproduction measurements with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Meson photo- production is being used as a tool for various investigations, including the spectroscopy of baryons and mesons and the search for vector-meson medium modifications.

On a low energy, strong interaction model, unifying mesons and baryons

International Nuclear Information System (INIS)

Kalafatis, D.

1993-03-01

This thesis is concerned with the study of a unified theory of mesons and baryons. An effective Lagrangian with the low mass mesons, generalizing the Skyrme model, is constructed. The vector meson fields are introduced as gauge fields in the linear sigma model instead of the non linear sigma model. Topological soliton solutions of the model are examined and the nucleon-nucleon interaction in the product approximation is investigated. The leading correction to the classical skyrmion mass, the Casimir energy, is evaluated. The problem of the stability of topological solitons when vector fields enter the chiral Lagrangian is also studied. It is shown that the soliton is stable in very much the same way as with the ωmeson and that peculiar classical doublet solutions do not exist

Measurement of Charmless B to Vector-Vector decays at BaBar

International Nuclear Information System (INIS)

Olaiya, Emmanuel

2011-01-01

The authors present results of B → vector-vector (VV) and B → vector-axial vector (VA) decays B 0 → φX(X = φ,ρ + or ρ 0 ), B + → φK (*)+ , B 0 → K*K*, B 0 → ρ + b 1 - and B + → K* 0 α 1 + . The largest dataset used for these results is based on 465 x 10 6 Υ(4S) → B(bar B) decays, collected with the BABAR detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC). Using larger datasets, the BABAR experiment has provided more precise B → VV measurements, further supporting the smaller than expected longitudinal polarization fraction of B → φK*. Additional B meson to vector-vector and vector-axial vector decays have also been studied with a view to shedding light on the polarization anomaly. Taking into account the available errors, we find no disagreement between theory and experiment for these additional decays.

On parasupersymmetric oscillators and relativistic vector mesons in constant magnetic fields

Science.gov (United States)

Debergh, Nathalie; Beckers, Jules

1995-01-01

Johnson-Lippmann considerations on oscillators and their connection with the minimal coupling schemes are visited in order to introduce a new Sakata-Taketani equation describing vector mesons in interaction with a constant magnetic field. This new proposal, based on a specific parasupersymmetric oscillator-like system, is characterized by real energies as opposed to previously pointed out relativistic equations corresponding to this interacting context.

Light vector meson production at forward rapidity in pp collisions at the LHC with the ALICE detector

CERN Document Server

Incani, Elisa; Usai, Gianluca

Low-mass vector mesons ($\\rho$, $\\omega$ and $\\phi$) give us information on the hot and dense state of strongly interacting matter produced in heavy ion collisions. In fact, in the QGP an enhancement of the strange particle production should be present (strangeness enhancement), which means a N$\\phi$ /N$\\rho+\\omega$ ratio increasing in A-A collisions with respect to pp collisions; pp collisions provide a reference for these studies. Vector meson production in pp collisions is also useful by itself, to study soft Quantum ChromoDynamics (QCD) in the LHC energy range, since calculations in this regime are based on QCD inspired phenomenological models that must be tuned to the data. The ALICE experiment at the LHC can access vector mesons produced at forward rapidity through their decays in muon pairs. We will show the ratio $N\\phi$ /N$\\rho+\\omega$ vs pT, the ratios $\\sigma_\\rho/\\sigma_\\omega$ and $\\sigma_\\phi/\\sigma_\\omega$, and the $\\phi$ and $\\omega$ pT and rapidity differential cross sections for the data sam...

Production rates of strange vector mesons at the Z0 resonance

International Nuclear Information System (INIS)

Dima, M.O.

1997-05-01

This dissertation presents a study of strange vector meson production, open-quotes leading particleclose quotes effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z 0 . The measurements were performed in e + e - collisions at the Stanford Linear Accelerator Center (SLAC) with the SLC Large Detector (SLD) experiment. A new generation particle ID system, the SLD Cerenkov Ring Imaging Detector (CRID) is used to discriminate kaons from pions, enabling the reconstruction of the vector mesons over a wide momentum range. The inclusive production rates of φ and K* 0 and the differential rates versus momentum were measured and are compared with those of other experiments and theoretical predictions. The high longitudinal polarisation of the SLC electron beam is used in conjunction with the electroweak quark production asymmetries to separate quark jets from antiquark jets. K* 0 production is studied separately in these samples, and the results show evidence for the open-quotes leading particleclose quotes effect. The difference between K* 0 production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation

What Can We Learn from Hadronic and Radiative Decays of Light Mesons?

Science.gov (United States)

Kubis, Bastian

2013-04-01

Chiral perturbation theory offers a powerful tool for the investigation of light pseudoscalar mesons. It incorporates the fundamental symmetries of QCD, interrelates various processes, and allows to link these to the light quark masses. Its shortcomings lie in a limited energy range: the radius of convergence of the chiral expansion is confined to below resonance scales. Furthermore, the strongest consequences of chiral symmetry are manifest for pseudoscalars (pions, kaons, eta) only: vector mesons, e.g., have a severe impact in particular for reactions involving photons. In this talk, I advocate dispersions relations as another model-independent tool to extend the applicability range of chiral perturbation theory. They even allow to tackle the physics of vector mesons in a rigorous way. It will be shown how dispersive methods can be used to resum large rescattering effects, and to provide model-independent links between hadronic and radiative decay modes. Examples to be discussed will include decays of the eta meson, giving access to light-quark-mass ratios or allowing to test the chiral anomaly; and meson transition form factors, which have an important impact on the hadronic light-by-light-scattering contribution to the anomalous magnetic moment of the muon.

Mass spectrum of vector mesons in the relativistic model of quasi-independent quarks

International Nuclear Information System (INIS)

Savrin, V.I.; Khrushchev, V.V.; Semenov, S.V.

1988-01-01

Mass values of mesons with J PC =1 -- built of u-, d-, s-, c-, b-quarks in S-states have been found with the help of numerical solutions of Dirac equation. The potential entering the equation consists of the scalar linear potential and the Coulomb vector one. The main contribution into spectra dependence on the radial quantum number for light quarks is shown to give the cnfinement scalar flavour independent potential: V c (r)=κ 2 r, at parameter value κ∼ 0.42 GeV. The calculated mass values are in agreement with ∼ 5% accuracy with the data for well established mesons

The dipole representation of vector meson electroproduction beyond leading twist

International Nuclear Information System (INIS)

Besse, A.; Szymanowski, L.; Wallon, S.

2013-01-01

We link the recent computation beyond leading twist of the impact factor of the transition γ T ⁎ →ρ T performed in the light-cone collinear approach, to the dipole picture by expressing the hard part of the process through its Fourier transform in coordinate space. We show that in the Wandzura–Wilczek approximation the impact factor up to twist 3 factorises in the wave function of the photon combined with the distribution amplitudes of the ρ-meson and the colour dipole scattering amplitude with the t-channel gluons. We show also that beyond the Wandzura–Wilczek approximation, the hard contribution of the amplitude still exhibits the signature of the interaction of a single colour dipole with the t-channel gluons. This result allows a phenomenological approach of the helicity amplitudes of the leptoproduction of vector meson, by combining our results to a dipole/target scattering amplitude model.

Exclusive vector meson production in pp collisions at the COMPASS experiment

International Nuclear Information System (INIS)

Bernhard, Johannes

2014-01-01

Mechanisms for particle production in proton-proton collisions at intermediate energies are studied within the COMPASS collaboration using the COMPASS spectrometer at the M2 beam line of the SPS at CERN. The possible production mechanisms are investigated using the production of the vector mesons ω and φ and include resonant diffractive excitation of the beam proton with a subsequent decay of the resonance, central production and the related ''shake-off'' mechanism. The data which were used for this thesis were collected in the years 2008 and 2009 with a 190 GeV/c proton beam impinging on a liquid hydrogen target that was surrounded by a recoil proton detector (RPD). The RPD is an integral part of the newly developed hadron trigger system for which in addition several new detectors have been build. The performances of both RPD and hadron trigger system are scrutinised and efficiency parameters are extracted. A method for reconstruction of recoil protons and for calibration is developed and described. The production of ω mesons is studied with the reaction pp → pωp, ω → π + π - π 0 and the production of φ mesons with the reaction pp → pφp, φ → K + K - for momentum transfers squared between 0.1 (GeV/c) 2 and 1 (GeV/c) 2 . The production ratio σ(pp → pφp)/σ(pp → pωp) is determined as a function of the longitudinal momentum fraction x F and compared to the OZI rule prediction. A significant violation of the OZI rule dependent on x F is found and discussed with respect to resonant structures in the pω mass spectrum. Removing the low pω/pφ mass region which includes these structures eliminates the x F dependence. In addition, the spin density matrix element ρ 00 , i.e. the spin alignment, for both ω and φ mesons is studied. One study is performed in the helicity frame that allows to discriminate resonant diffractive excitation. In a second study, a reference frame with respect to the direction of the momentum transfer

Angular distribution and rotations of frame in vector meson decays into lepton pairs

International Nuclear Information System (INIS)

Palestini, Sandro

2011-01-01

We discuss how the angular distribution of lepton pairs from decays of vector mesons depends on the choice of reference frame, and provide a geometrical description of the transformations of the coefficients of the angular distribution. Invariant expressions involving all coefficients are discussed, together with bounds and consistency relations.

Nondiffraction photoproduction of vector mesons and the photon structure function

International Nuclear Information System (INIS)

Badalyan, R.G.; Gulkanyan, H.R.

1988-01-01

In the framework of the recombination model of hadron production a self-consistent description of the available data on the inclusive spectra of the nondiffraction photoproduction of vector mesons in the fragmentation region of photons at high energies is obtained. The parameters of parton distribution in the hadron component of a photon are estimated and its structure is compared with the measurements of the photon structure function in γγ-interactions at low Q 2 . 15 refs.; 2 figs.; 1 tab

Low-energy meson physics (chiral theory)

International Nuclear Information System (INIS)

Volkov, M.K.; Pervushin, V.N.

1976-01-01

A quantum chiral theory which allows to obtain low-energy expansions of various hadron processes without introducing arbitrary parameters into the theory with the exception of hadron masses and interaction constants is presented. A hypothesis about the dynamic symmetry of strong interactions is suggested. The interaction lagrangian is derived which satisfies conditions of the dynamic symmetry. Examples of the use of the quantum chiral theory for describing low-energy processes of meson interaction are given. It is noted that the results obtained reproduce the actual qualitative pattern of various physical processes and in most cases result in good quantitative agreement with experiments

The dipole representation of vector meson electroproduction beyond leading twist

Energy Technology Data Exchange (ETDEWEB)

Besse, A. [LPT, Universite Paris-Sud, CNRS, 91405, Orsay (France); Szymanowski, L. [National Center for Nuclear Research (NCBJ), Warsaw (Poland); Wallon, S., E-mail: wallon@th.u-psud.fr [LPT, Universite Paris-Sud, CNRS, 91405, Orsay (France); UPMC Univ. Paris 06, Faculte de Physique, 4 place Jussieu, 75252 Paris Cedex 05 (France)

2013-02-01

We link the recent computation beyond leading twist of the impact factor of the transition {gamma}{sub T}{sup Low-Asterisk }{yields}{rho}{sub T} performed in the light-cone collinear approach, to the dipole picture by expressing the hard part of the process through its Fourier transform in coordinate space. We show that in the Wandzura-Wilczek approximation the impact factor up to twist 3 factorises in the wave function of the photon combined with the distribution amplitudes of the {rho}-meson and the colour dipole scattering amplitude with the t-channel gluons. We show also that beyond the Wandzura-Wilczek approximation, the hard contribution of the amplitude still exhibits the signature of the interaction of a single colour dipole with the t-channel gluons. This result allows a phenomenological approach of the helicity amplitudes of the leptoproduction of vector meson, by combining our results to a dipole/target scattering amplitude model.

Vector meson exchanges and CP asymmetry in K± → π±π0

International Nuclear Information System (INIS)

Riazuddin; Paver, N.; Simeoni, F.

1993-07-01

Using a current algebra framework, we discuss the contribution of vector meson exchanges to the CP violating asymmetry in the decay K ± → π±π 0 , resulting from the interference of the K → ππ amplitude with the radiative correction K → ππγ. (author). 11 refs, 2 figs

Search for a PHI' vector meson in diffractive photoproduction of K+K-π+π-

International Nuclear Information System (INIS)

Atkinson, M.; Davenport, M.; Flower, P.; Hutton, J.S.; Kumar, B.R.; Morris, J.A.G.; Morris, J.V.; Patrick, G.N.; Sharp, P.H.; Bussey, P.J.; Dainton, J.B.; Paterson, C.; Raine, C.; Skillicorn, I.O.; Smith, K.M.; Brodbeck, T.J.; Clegg, A.B.; Flynn, P.J.; Henderson, R.C.W.; Newton, D.; Axon, T.J.; Barberis, D.; Dickinson, B.; Donnachie, A.; Ellison, R.J.; Hughes-Jones, R.E.; Ibbotson, M.; Lafferty, G.D.; Lane, J.B.; Mercer, D.; Thompson, R.J.; Waite, A.P.; Worsell, M.F.; Levy, J.M.; Laberrigue, J.; La Vaissiere, C. de; Yiou, T.P.; Brookes, G.R.; Bunn, J.J.; Galbraith, W.; McClatchey, R.H.

1986-01-01

A study of photoproduction of K + K - π + π - shows a broad threshold enhancement, about 30% of which is due to Ksup(*)Kπ production. This Ksup(*)Kπ component shows no dynamical features indicative of the existence of a PHI' vector meson in this channel. (orig.)

Exclusive neutrino production of a charmed vector meson and transversity gluon generalized parton distributions

Science.gov (United States)

Pire, B.; Szymanowski, L.

2017-12-01

We calculate at the leading order in αs the QCD amplitude for exclusive neutrino production of a D* or Ds* charmed vector meson on a nucleon. We work in the framework of the collinear QCD approach where generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions. We include O (mc) terms in the coefficient functions and the O (mD) term in the definition of heavy meson distribution amplitudes. The show that the analysis of the angular distribution of the decay D(s) *→D(s )π allows us to access the transversity gluon GPDs.

The QCD model of hadron cores of the meson theory

International Nuclear Information System (INIS)

Pokrovskii, Y.E.

1985-01-01

It was shown that in the previously proposed QCD model of hadron cores the exchange and self-energy contributions of the virtual quark-antiquark-gluon cloud on the outside of a bag which radius coincides with the hardon core radius of the meson theory (∼ 0.4 Fm) have been taken into account at the phenomenological level. Simulation of this cloud by the meson field results in realistic estimations of the nucleon's electroweak properties, moment fractions carried by gluons, quarks, antiquarks and hadron-hadron interaction cross-sections within a wide range of energies. The authors note that the QCD hadron core model proposed earlier not only realistically reflects the hadron masses, but reflects self-consistently main elements of the structure and interaction of hadrons at the quark-gluon bag radius (R - 0.4Fm) being close to the meson theory core radius

Extended vector-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke, E-mail: rampei@th.phys.titech.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: yoshida@th.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2017-01-01

Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.

Scattering amplitudes to all orders in meson exchange

International Nuclear Information System (INIS)

Silbar, R.R.; Mattis, M.P.

1990-01-01

As the number of colors in QCD, N C , becomes large, it is possible to sum up all meson-exchange contributions, however arbitrarily complicated, to meson-baryon and baryon-baryon scattering. A semi-classical structure for the two-flavor theory emerges, in close correspondence to vector-meson-augmented Skyrme models. In this limit, baryons act as extended static sources for the classical meson fields. This leads to non-linear differential equations for the classical meson fields which can be solved numerically for static radial (hedgehog-like) solutions. The non-linear terms in the equations of motion for the quantized meson fields can then be simplified, to leading order in 1/N C , by replacing all factors of the meson field but one by the previously-found classical field. This results in linear, Schroedinger-like equations, which are easily solved. For the meson-baryon case the solution can be subsequently analyzed to obtain the phase shifts for the scattering and, from these, the baryon resonance spectrum of the model. As the warm-up, we have carried out this calculation for the simple case of σ mesons only, finding sensible results. 8 refs., 3 figs

Double vector meson production in the International Linear Collider

Energy Technology Data Exchange (ETDEWEB)

Carvalho, F. [Universidade Federal de Sao Paulo, Departamento de Ciencias Exatas e da Terra, Diadema, SP (Brazil); Goncalves, V.P. [Universidade Federal de Pelotas, High and Medium Energy Group, Instituto de Fisica e Matematica, Caixa Postal 354, Pelotas, RS (Brazil); Moreira, B.D.; Navarra, F.S. [Universidade de Sao Paulo, Instituto de Fisica, C.P. 66318, Sao Paulo, SP (Brazil)

2015-08-15

In this paper we study double vector meson production in γγ interactions at high energies and estimate, using the color dipole picture, the main observables which can be probed at the International Linear Collider (ILC). The total γ(Q{sub 1}{sup 2}) + γ(Q{sub 2}{sup 2}) → V{sub 1} + V{sub 2} cross sections for V{sub i} = ρ, J/ψ, and Υ are computed and the energy and virtuality dependencies are studied in detail. Our results demonstrate that the experimental analysis of this process is feasible at the ILC and it can be useful to constrain the QCD dynamics at high energies. (orig.)

A theory of scalar mesons

International Nuclear Information System (INIS)

Hooft, G. t'; Isidori, G.; Maiani, L.; Polosa, A.D.; Riquer, V.

2008-01-01

We discuss the effect of the instanton induced, six-fermion effective Lagrangian on the decays of the lightest scalar mesons in the diquark-antidiquark picture. This addition allows for a remarkably good description of light scalar meson decays. The same effective Lagrangian produces a mixing of the lightest scalars with the positive parity qq-bar states. Comparing with previous work where the qq-bar mesons are identified with the nonet at 1200-1700 MeV, we find that the mixing required to fit the mass spectrum is in good agreement with the instanton coupling obtained from light scalar decays. A coherent picture of scalar mesons as a mixture of tetraquark states (dominating in the lightest mesons) and heavy qq-bar states (dominating in the heavier mesons) emerges

Renormalizable Electrodynamics of Scalar and Vector Mesons. Part II

Science.gov (United States)

Salam, Abdus; Delbourgo, Robert

1964-01-01

The "gauge" technique" for solving theories introduced in an earlier paper is applied to scalar and vector electrodynamics. It is shown that for scalar electrodynamics, there is no {lambda}φ*2φ2 infinity in the theory, while with conventional subtractions vector electrodynamics is completely finite. The essential ideas of the gauge technique are explained in section 3, and a preliminary set of rules for finite computation in vector electrodynamics is set out in Eqs. (7.28) - (7.34).

Off-diagonal helicity density matrix elements for vector mesons produced in polarized e+e- processes

International Nuclear Information System (INIS)

Anselmino, M.; Murgia, F.; Quintairos, P.

1999-04-01

Final state q q-bar interactions give origin to non zero values of the off-diagonal element ρ 1,-1 of the helicity density matrix of vector mesons produced in e + e - annihilations, as confirmed by recent OPAL data on φ, D * and K * 's. New predictions are given for ρ 1,-1 of several mesons produced at large x E and small p T - i.e. collinear with the parent jet - in the annihilation of polarized 3 + and 3 - , the results depend strongly on the elementary dynamics and allow further non trivial tests of the standard model. (author)

Production rates of strange vector mesons at the Z⁰ resonance

Energy Technology Data Exchange (ETDEWEB)

Dima, Mihai O. [Stanford Univ., CA (United States)

1997-05-01

This dissertation presents a study of strange vector meson production, "leading particle" effect and a first direct measurement of the strangeness suppression parameter in hadronic decays of the neutral electroweak boson, Z. The measurements were performed in e⁺e^- collisions at the Stanford Linear Accelerator Center (SLAC) with the SLC Large Detector (SLD) experiment. A new generation particle ID system, the SLD Cerenkov Ring Imaging Detector (CRID) is used to discriminate kaons from pions, enabling the reconstruction of the vector mesons over a wide momentum range. The inclusive production rates of ρ and K*⁰ and the differential rates versus momentum were measured and are compared with those of other experiments and theoretical predictions. The high longitudinal polarisation of the SLC electron beam is used in conjunction with the electroweak quark production asymmetries to separate quark jets from antiquark jets. K*⁰ production is studied separately in these samples, and the results show evidence for the "leading particle" effect. The difference between K*⁰ production rates at high momentum in quark and antiquark jets yields a first direct measurement of strangeness suppression in jet fragmentation.

Oscillations of neutral K mesons in the theory of dynamical expansion of the weak interaction theory or in the theory of dynamical analogy of the Cabibbo-Kobayashi-Maskawa matrices

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

1998-01-01

The elements of the theory of dynamical expansion of the weak interaction theory working on the tree level, i.e., the theory of dynamical analogy of Cabibbo-Kobayashi-Maskawa matrices, are given. The equation for mass difference of K 1 0 , K 2 0 mesons or the length of K 0 -, K bar 0 - meson oscillations is calculated. In the framework of this theory the oscillations of K 0 , K 0 mesons which arise at violation of strangeness by B bosons are considered. The general conclusion is: the length of K 0 -, K 0 -meson oscillations is proportional to the mass of B boson (which changes strangeness) in the fourth degree

Photoproduction of vector mesons off nucleons near threshold

International Nuclear Information System (INIS)

Friman, B.

1995-01-01

A simple meson-exchange model is proposed for the photoproduction of ρ- and ω-mesons off protons near threshold. This model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). This phenomenological interaction is applied to estimate the leading contribution to the self-energy of ρ-mesons in matter. The implications of our calculation for experimental studies of the ρ-meson mass in nuclei are discussed. (author)

Meson theory and nuclear matter

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

An attempt is made to justify the use of the concept of a 'mesic fluid' in connection with the structure of nuclear matter. A transformation is made of the usual symmetric pseudo-scalar meson theory to bring into evidence certain saturation properties, which provide a natural basis for the use of a 'self-consistent' field in the discussion of nuclear structure. Fluctuations about this semi-classical saturated state will give rise to residual interparticle forces within the nucleus, and are also briefly considered in relation to electromagnetic interactions. (author). 5 refs

Photoproduction of vector mesons off nucleons near threshold

International Nuclear Information System (INIS)

Friman, B.; Soyeur, M.

1995-11-01

We propose a simple meson-exchange model of the photoproduction of ρ-and ω-mesons off protons near threshold (E γ < or∼2 GeV). We show that this model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). We use this phenomenological interaction to estimate the leading contribution to the self-energy of ρ-mesons in matter. We discuss the implications of our calculation for experimental studies of the ρ-meson mass in nuclei. (orig.)

Light Meson Distribution Amplitudes

CERN Document Server

Arthur, R.; Brommel, D.; Donnellan, M.A.; Flynn, J.M.; Juttner, A.; de Lima, H.Pedroso; Rae, T.D.; Sachrajda, C.T.; Samways, B.

2010-01-01

We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\\pi$ and $K$) and the longitudinally polarised vector mesons ($\\rho$, $K^*$ and $\\phi$) as part of the UKQCD and RBC collaborations' $N_f=2+1$ domain-wall fermion phenomenology programme. These quantities were obtained with a good precision and, in particular, the expected effects of $SU(3)$-flavour symmetry breaking were observed. Operators were renormalised non-perturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, $16^3\\times 32$ and $24^3\\times 64$, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, $32^3\\times64$, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.

Neutron stars in relativistic mean field theory with isovector scalar meson

International Nuclear Information System (INIS)

Kubis, S.; Kutschera, M.; Stachniewicz, S.

1998-01-01

We study the equation of state (EOS) of β-stable dense matter and models of neutron stars in the relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the δ-meson (a 0 (980)). A range of values of the δ-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E s ∼30 MeV. We find that the quantity most sensitive to the δ-meson coupling is the proton fraction of neutron star matter. It increases significantly in the presence of the δ-field. The energy per baryon also increases but the effect is smaller. The EOS becomes slightly stiffer and the maximum neutron star mass increases for stronger δ-meson coupling. (author)

High-energy behavior of fermion-meson and meson-meson scattering in a supersymmetric field theory

International Nuclear Information System (INIS)

Opoien, J.W.

1978-01-01

The high-energy behavior of fermion-boson and boson-boson scattering amplitudes of a supersymmetric field theory containing a spin-1/2 fermion field, a scalar field, and a pseudoscalar field is investigated. The results can be easily modified to apply to the Yukawa model and the neutral version of the linear sigma model. The results are also compared to those of fermion-fermion scattering in the same model. In the leading-logarithm approximation, ladders with fermions running along the sides in the t channel and mesons as rungs dominate in each order of two classes of diagrams. The sum of the dominant series give rise to fixed Regge cuts for all amplitudes in each of the three theories. All amplitudes in the supersymmetric theory possess a definite signature factor, while the amplitudes for fermion-fermion and fermion-antifermion scattering in the Y model and the sigma model lack it. The results of the supersymmetric theory are also compared to the results of the spontaneously broken non-Abelian gauge theory

Strange mesonic transition form factor

International Nuclear Information System (INIS)

Goity, J.L.; Musolf, M.J.

1996-01-01

The strange-quark vector current ρ-to-π meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a φ-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by φ-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cutoff mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciable in moderate-parallel Q 2 parallel parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon. copyright 1996 The American Physical Society

Meson effective mass in the isospin medium in hard-wall AdS/QCD model

Energy Technology Data Exchange (ETDEWEB)

Mamedov, Shahin [Gazi University, Department of Physics, Ankara (Turkey); Baku State University, Institute for Physical Problems, Baku (Azerbaijan); Azerbaijan National Academy of Sciences, Institute of Physics, Baku (Azerbaijan)

2016-02-15

We study a mass splitting of the light vector, axial-vector, and pseudoscalar mesons in the isospin medium in the framework of the hard-wall model. We write an effective mass definition for the interacting gauge fields and scalar field introduced in gauge field theory in the bulk of AdS space-time. Relying on holographic duality we obtain a formula for the effective mass of a boundary meson in terms of derivative operator over the extra bulk coordinate. The effective mass found in this way coincides with the one obtained from finding of poles of the two-point correlation function. In order to avoid introducing distinguished infrared boundaries in the quantization formula for the different mesons from the same isotriplet we introduce extra action terms at this boundary, which reduces distinguished values of this boundary to the same value. Profile function solutions and effective mass expressions were found for the in-medium ρ, a{sub 1}, an π mesons. (orig.)

Vector meson dominance and pointlike coupling of the photon in soft and hard processes

International Nuclear Information System (INIS)

Paul, E.

1990-05-01

Recent experimental results on photoproduction of hadrons probe the nature of the interacting photon over a wide kinematical range from soft to hard processes. Single inclusive spectra and energy flows of the final state charged particles are well described by assuming that photon production data are built up by an incoherent superposition of a soft Vector-Meson-Dominance component and a hard pointlike photon component. (orig.)

Neutron stars in relativistic mean field theory with isovector scalar meson

Energy Technology Data Exchange (ETDEWEB)

Kubis, S.; Kutschera, M.; Stachniewicz, S. [H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1998-03-01

We study the equation of state (EOS) of {beta}-stable dense matter and models of neutron stars in the relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the {delta}-meson (a{sub 0}(980)). A range of values of the {delta}-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E{sub s}{approx}30 MeV. We find that the quantity most sensitive to the {delta}-meson coupling is the proton fraction of neutron star matter. It increases significantly in the presence of the {delta}-field. The energy per baryon also increases but the effect is smaller. The EOS becomes slightly stiffer and the maximum neutron star mass increases for stronger {delta}-meson coupling. (author) 8 refs, 6 figs, 2 tabs

Quarkonia and heavy-light mesons in a covariant quark model

Directory of Open Access Journals (Sweden)

Leitão Sofia

2016-01-01

Full Text Available Preliminary calculations using the Covariant Spectator Theory (CST employed a scalar linear confining interaction and an additional constant vector potential to compute the mesonic mass spectra. In this work we generalize the confining interaction to include more general structures, in particular a vector and also a pseudoscalar part, as suggested by a recent study [1]. A one-gluon-exchange kernel is also implemented to describe the short-range part of the interaction. We solve the simplest CST approximation to the complete Bethe-Salpeter equation, the one-channel spectator equation, using a numerical technique that eliminates all singularities from the kernel. The parameters of the model are determined through a fit to the experimental pseudoscalar meson spectra, with a good agreement for both quarkonia and heavy-light states.

Studies on inclusive meson resonance and particle production

International Nuclear Information System (INIS)

Saarikko, Heimo

1978-01-01

Production and decay of meson resonances are studied in medium energy meson-proton collisions. Strong evidence is found that hadronic collisions are dominated by resonance production. Especially the vector mesons have often large inclusive cross sections, typically of the order of few millibarns at the present energies. In all, a majority of pions and kaons appear to be decay products of resonances or other unstable particles. The detailed kinematics of the parent resonance's decays is found to play an important role in determining inclusive pion spectra. The squared transverse momentum distributions of hadrons heavier than the pion appear to have in common an exponential behaviour, with a universal slope for the esponential fall-off. The observed vector meson yields suggest that only a small fraction of the direct lepton production observed at large transverse momentum in nucleon-nucleon interactions is accounted for by the ''old'' vector mesons. An attempt has been made to separate out the central production and fragmentation components of the meson production. Both the central production and the fragmentation of the incoming meson are found to be important mechanisms in the non-strange meson production whereas the central production of strange meson resonances is rare at our energies. The ratios of the observed meson yields are found to be generally in good agreement with a simple quark-counting model. (author)

Meson-baryon interactions in unitarized chiral perturbation theory

International Nuclear Information System (INIS)

Garcia Recio, G.; Nieves, J.; Ruiz Arriola, E.; Vicente Vacas, M.

2003-01-01

Meson-Baryon Interactions can be successfully described using both Chiral Symmetry and Unitarity. The s-wave meson-baryon scattering amplitude is analyzed in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry in the potential. Two body coupled channel unitarity is exactly preserved. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. Off-shell behavior is parameterized in terms of low energy constants. The relation to the heavy baryon limit is discussed. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths baryonic resonances of the N(1535), N(1670), Λ(1405) and Λ(1670) resonances which compare well with accepted numbers

Cross section measurement of vector meson quasi-photoproduction at high four-momentum transfer using the ZEUS detector at the HERA collider

Energy Technology Data Exchange (ETDEWEB)

Klimek, K.H.

2001-11-01

Photoproduction of vector mesons, {gamma}p {yields} VY, where Y is the system into which the proton dissociates, has been measured in e{sup +}p interactions with the ZEUS detector at HERA using an integrated luminosity of 24 pb{sup -1}. The data were taken at a photon-proton center-of-mass energy W {approx_equal} 100 GeV and extend up to -t = 10 GeV{sup 2}, where t is the square of the four-momentum transferred to the vector meson. The differential cross section d{sigma}/dt for {rho}{sup 0}, {phi} and J/{psi} production are compared to the expectations of phenomenological models. (orig.)

Photoproduction of Inelastic and Elastic $J/\\psi$ Vector Mesons

Energy Technology Data Exchange (ETDEWEB)

Stundzia, Audrius Bronius [Toronto U.

1992-06-01

Results and analysis on the inelastic and elastic photoproduction of $J /\\psi$ vector mesons by Fermilab experiment E691 are presented. The inelastic, deep inelastic, coherent elastic and incoherent elastic cross sections were measured at ($E_{\\gamma}$) = 145 GeV. The $d\\sigma / dzdp^2_{\\tau}$} distribution and the photon energy dependence of the cross sections for these production processes were also measured. The deep inelastic $J /\\psi$ was analyzed in the colour-singlet photon-gluon-fusion model. It was found that the $d\\sigma / dzdp^2_{\\tau}$ distribution and the the rise of the cross section with $E\\gamma$ are both well described by a relatively soft gluon distribution [xG( x) $\\alpha$ ($1 - x )^{ng}$, where $n_g$ = 6.5 ± 1.1 (stat.)$^{+1.0}_{-0.6}$(syst.)].

Test of OZI violation in vector meson production with COMPASS

CERN Document Server

Bernhard, Johannes

2011-01-01

The COMPASS experiment at CERN SPS completed its data taking with hadron beams ($p,\\pi, K$) in the years 2008 and 2009 by collecting a large set of data using different targets (H$_{2}$, Pb, Ni, W). These data are dedicated to hadron spectroscopy, where the focus is directed to the search for exotic bound states of quarks and gluons (hybrids, glueballs). The production of such states is known to be favoured in glue-rich environments, e.g. so-called OZI-forbidden processes. The OZI rule postulates that processes with disconnected quark line diagrams are forbidden. On the one hand, the study of the degree of OZI violation in vector meson production yields the possibilty to learn more about the involved production mechanisms. On the other hand it helps to understand the nucleon's structure itself. Contrary to former experiments, the large data sample allows for detailed studies in respect to Feynman's variable $x_{F}$. We present results from the ongoing analysis on the comparison of $\\omega$ and $\\phi$ vector m...

Meson and baryon families as vibronic states in sl(2) quantum universal enveloping algebra

International Nuclear Information System (INIS)

Iwao, Syurei; Ono, Yasuji

1990-01-01

A mass formula of the q-deformed modified harmonic oscillator type in the sl(2) quantum universal enveloping algebra is proposed for the meson and baryon families, by taking into account the known theories as a guide. Specifying the vibronic quantum number, the deformation parameter and associated ones of the theory are determined from available data for the scalar, pseudoscalar, vector meson and baryon families. The parameters determined from totally ten families not only predict many unobserved states, but also give restrictions on the observable number of states. The method may admit taking into account non-perturbative effects. (author)

Double vector meson production in γγ interactions at hadronic colliders

Energy Technology Data Exchange (ETDEWEB)

Goncalves, V.P. [Lund University, Department of Astronomy and Theoretical Physics, Lund (Sweden); Universidade Federal de Pelotas, High and Medium Energy Group, Instituto de Fisica e Matematica, Pelotas, RS (Brazil); Moreira, B.D.; Navarra, F.S. [Universidade de Sao Paulo, Instituto de Fisica, C.P. 66318, Sao Paulo, SP (Brazil)

2016-03-15

In this paper we revisit the double vector meson production in γγ interactions at heavy ion collisions and present, by the first time, predictions for the ρρ and J/ΨJ/Ψ production in proton.nucleus and proton.proton collisions. In order to obtain realistic predictions for rapidity distributions and total cross sections for the double vector production in ultra peripheral hadronic collisions we take into account the description of γγ → VV cross section at lowenergies as well as its behavior at large energies, associated to the gluonic interaction between the color dipoles. Our results demonstrate that the double ρ production is dominated by the low energy behavior of the γγ → VV cross section. In contrast, for the double J/Ψ production, the contribution associated to the description of the QCD dynamics at high energies contributes significantly, mainly in pp collisions. Predictions for the RHIC, LHC, FCC, and CEPC-SPPC energies are shown. (orig.)

The role of resonances in chiral perturbation theory

International Nuclear Information System (INIS)

Ecker, G.; Rafael, E. de

1988-09-01

The strong interactions of low-lying meson resonances (spin ≤ 1) with the octet of pseudoscalar mesons (π,Κ,η) are considered to lowest order in the derivative expansion of chiral SU(3). The resonance contributions to the coupling constants of the O(p 4 ) effective chiral lagrangian involving pseudoscalar fields only are determined. These low-energy coupling constants are found to be dominated by the resonance contributions. Although we do not treat the vector and axial-vector mesons as gauge bosons of local chiral symmetry, vector meson dominance emerges as a prominent result of our analysis. As a further application of chiral resonance couplings, we calculate the electromagnetic pion mass difference to lowest order in chiral perturbation theory with explicit resonance fields. 29 refs., 2 figs., 5 tabs. (Author)

The growth with energy of vector meson photo-production cross-sections and low $x$ evolution

CERN Document Server

Hentschinski, Martin

2017-01-01

We investigate the energy dependence of the exclusive photo-production cross-sections of vector mesons $J/\\Psi$ and $\\Upsilon$ on protons. In particular we are interested in the question whether their energy dependence has a description in terms of perturbative low $x$ (i.e. BFKL) evolution. As an update to the original publication [1] we include recent LHCb 13 TeV results in our comparison with data.

Meson-baryon scattering in manifestly Lorentz invariant chiral perturbation theory

International Nuclear Information System (INIS)

Mai, Maxim; Bruns, Peter C.; Kubis, Bastian; Meissner, Ulf-G.

2011-01-01

We analyze meson-baryon scattering lengths in the framework of covariant baryon chiral perturbation theory at leading one-loop order. We compute the complete set of matching relations between the dimension-two low-energy constants in the two- and three-flavor formulations of the theory. We derive new two-flavor low-energy theorems for pion-hyperon scattering that can be tested in lattice simulations.

Vector meson production in the final state K K of photon-photon collisions

Energy Technology Data Exchange (ETDEWEB)

Althoff, M; Braunschweig, W; Gerhards, R; Kirschfink, J F; Martyn, H U; Rosskamp, P; Wallraff, W; Bock, B; Eisenmann, Y; Fischer, H M

1986-08-01

Vector meson production is studied in the reaction ->K K . A clear PHI(1020) signal is seen in the K K mass distribution and a Ksup(*0)(890) signal is visible in the Ksup(+-) sup(-+) one. Both do not seem to be strongly correlated with quasi two body final states. Cross sections for the processes ->K K , ->PHI , ->Ksup(*0)Ksup(+-) sup(-+) and upper limits for the production of duction of PHIrho, PHIPHI and Ksup(*0)Ksup(*0) are given as function of the invariant mass.

Meson theory of charge-dependent nuclear forces. Chapter 10

International Nuclear Information System (INIS)

Henley, E.M.; Miller, G.A.

1979-01-01

Although the charge dependence is a small effect it is a useful probe for nuclear structure and forces details. The authors are primarily concerned with the short-range meson-theoretic origin of these forces. They discuss recent experimental and theoretical advances and give applications and possible tests of the theory. (D.H.)

Neutron stars in relativistic mean field theory with isovector scalar meson

International Nuclear Information System (INIS)

Kubis, S.; Kutschera, M.; Stachniewicz, S.

1996-12-01

We study the equation of state (EOS) of neutron star matter in a relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the δ-meson [a 0 (980)]. A range of values of the δ-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E s ∼ 30 MeV. We find that proton fraction of neutron star matter is higher in the presence of the δ-field whereas the energy per particle is lower. The EOS becomes slightly stiffer and the maximum mass of the neutron star increased with increasing δmeson coupling. The effect is stronger for soft EOS. (author). 7 refs, 6 figs, 1 tab

Neutron stars in relativistic mean field theory with isovector scalar meson

Energy Technology Data Exchange (ETDEWEB)

Kubis, S.; Kutschera, M.; Stachniewicz, S. [Institute of Nuclear Physics, Cracow (Poland)

1996-12-01

We study the equation of state (EOS) of neutron star matter in a relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the {delta}-meson [a{sub 0}(980)]. A range of values of the {delta}-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E{sub s} {approx} 30 MeV. We find that proton fraction of neutron star matter is higher in the presence of the {delta}-field whereas the energy per particle is lower. The EOS becomes slightly stiffer and the maximum mass of the neutron star increased with increasing {delta}meson coupling. The effect is stronger for soft EOS. (author). 7 refs, 6 figs, 1 tab.

The dipole asymptotic behaviour of the proton form factor as a contribution of vector mesons and central region

International Nuclear Information System (INIS)

Skachkov, N.B.; Solovtsov, I.L.

1976-01-01

In the method of the invariant description of the proton spatial distribution, vector mesons are found to contribute to the distribution only at distances larger than the proton Compton wavelength. The account of the central part contribution leads to a formula describing well the experimental data

Infrared equivalence of strongly and weakly coupled gauge theories

International Nuclear Information System (INIS)

Olesen, P.

1975-10-01

Using the decoupling theorem of Apelquist and Carazzone, it is shown that in terms of Feynman diagrams the pure Yang-Mills theory is equivalent in the infrared limit to a theory (zero-mass renormalized), where the vector mesons are coupled fo fermions, and where the fermions do not decouple. By taking enough fermions it is then shown that even though the pure Yang-Mills theory is characterized by the lack of applicability of perturbation theory, nevertheless the effective coupling in the equivalent fermion description is very weak. The effective mass in the zero-mass renormalization blows up. In the fermion description, diagrams involving only vector mesons are suppressed relative to diagrams containing at least one fermion loop. (Auth.)

Unified Chiral models of mesons and baryons

International Nuclear Information System (INIS)

Mendez-Galain, R.; Ripka, G.

1990-01-01

Unified Chiral models of mesons and baryons are presented. Emphasis is placed on the underlying quark structure of hadrons including the Skyrmion. The Nambu Jona-Lasinio model with vector mesons is discussed

Nuclear physics brought about by the π-mesons studied from field theory and experiments

International Nuclear Information System (INIS)

Toki, Hiroshi

2012-01-01

In nuclei π-mesons are playing key role. At first the important interactions of π-mesons in light nuclei is explained mentioning that the π-meson exchange force is tensor force. It is pointed out that the importance of π-meson is observed even in the deuterons. By the progress of computations it is possible at present to calculate nuclei up to the mass number of twelve. It is explained then how to handle the π-mesons in heavy nuclei referring to the discovery of the halo of 11 Li and its analysis. Due to the pseudo scalar properties of the π-mesons, tensor force is the strong nucleon-nucleon interaction. It has been necessary to go through numbers of trials and errors to arrive at the discovery of the proper tensor force analysis. It is shown to be possible to handle them in the Tensor-Optimized Shell Model (TOSM) based on the variation method. The explanation of the Extended Brueckner Hartree-Fock (EBHF) method obtained by combining the TOSM with the mean field theory used in the heavy nuclei is given. EBHF theory has the structure including high momentum components in the 2p2h wave functions. Calculated equation of state of symmetric nuclear matter is shown as a function of density in which important contribution of the tensor force is observed. Properties of nuclear matter are discussed. (S. Funahashi)

Nuclear matter in relativistic mean field theory with isovector scalar meson.

Energy Technology Data Exchange (ETDEWEB)

Kubis, S.; Kutschera, M. [Institute of Nuclear Physics, Cracow (Poland)

1996-12-01

Relativistic mean field (RMF) theory of nuclear matter with the isovector scalar mean field corresponding to the {delta}-meson [a{sub 0}(980)] is studied. While the {delta}-meson field vanishes in symmetric nuclear matter, it can influence properties of asymmetric nuclear matter in neutron stars. The RMF contribution due to {delta}-field to the nuclear symmetry energy is negative. To fit the empirical value, E{sub s}{approx}30 MeV, a stronger {rho}-meson coupling is required than in absence of the {delta}-field. The energy per particle of neutron star matter is than larger at high densities than the one with no {delta}-field included. Also, the proton fraction of {beta}-stable matter increases. Splitting of proton and neutron effective masses due to the {delta}-field can affect transport properties of neutron star matter. (author). 4 refs, 6 figs.

Nuclear matter in relativistic mean field theory with isovector scalar meson

International Nuclear Information System (INIS)

Kubis, S.; Kutschera, M.

1996-12-01

Relativistic mean field (RMF) theory of nuclear matter with the isovector scalar mean field corresponding to the δ-meson [a 0 (980)] is studied. While the δ-meson field vanishes in symmetric nuclear matter, it can influence properties of asymmetric nuclear matter in neutron stars. The RMF contribution due to δ-field to the nuclear symmetry energy is negative. To fit the empirical value, E s ∼30 MeV, a stronger ρ-meson coupling is required than in absence of the δ-field. The energy per particle of neutron star matter is than larger at high densities than the one with no δ-field included. Also, the proton fraction of β-stable matter increases. Splitting of proton and neutron effective masses due to the δ-field can affect transport properties of neutron star matter. (author). 4 refs, 6 figs

Observation of chi(c1) Decays into Vector Meson Pairs phi phi, omega omega, and omega phi

NARCIS (Netherlands)

Ablikim, M.; Achasov, M. N.; An, L.; An, Q.; An, Z. H.; Bai, J. Z.; Baldini, R.; Ban, Y.; Becker, J.; Berger, N.; Bertani, M.; Bian, J. M.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cao, G. F.; Cao, X. X.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denysenko, I.; Destefanis, M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Duan, M. Y.; Fan, R. R.; Fang, J.; Fang, S. S.; Feng, C. Q.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Greco, M.; Grishin, S.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, B.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jia, L. K.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kavatsyuk, M.; Komamiya, S.; Kuehn, W.; Lange, J. S.; Leung, J. K. C.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, Lei; Li, N. B.; Li, Q. J.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, G. C.; Liu, H.; Liu, H. B.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K.; Liu, K. Y.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Y. W.; Liu, Yong; Liu, Z. A.; Liu, Z. Q.; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, T.; Ma, X.; Ma, X. Y.; Maggiora, M.; Malik, Q. A.; Mao, H.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Muchnoi, N. Yu.; Nefedov, Y.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pelizaeus, M.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Pun, C. S. J.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, X. Y.; Sonoda, S.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. D.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tang, X. F.; Tian, H. L.; Toth, D.; Varner, G. S.; Wan, X.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Wen, Q. G.; Wen, S. P.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, W.; Wu, Z.; Xiao, Z. J.; Xie, Y. G.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Y.; Xu, Z. R.; Xu, Z. Z.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, M.; Yang, T.; Yang, Y.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, L.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, L.; Zhang, S. H.; Zhang, T. R.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, Jiawei; Zhao, Jingwei; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhao, Z. L.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zheng, Z. P.; Zhong, B.; Zhong, J.; Zhong, L.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Zuo, J. X.; Zweber, P.

2011-01-01

Using (106 +/- 4) x 10(6) psi(3686) events accumulated with the BESIII detector at the BEPCII e(+) e(-) collider, we present the first measurement of decays of chi(c1) to vector meson pairs phi phi, omega omega, and omega phi. The branching fractions are measured to be (4.4 +/- 0.3 +/- 0.5) x

Diffractive vector meson production in deep inelastic scattering

International Nuclear Information System (INIS)

Kamps, M. de.

1997-01-01

This thesis seeks to bring comfort to those who are appalled by the usual high level of violence in high energy physics. Although also here we engage in the customary vandalistic smashing together of two particles, the reaction we will study has a happy end in store for both of them. The subject of this thesis will be the reaction: e + p→e + pV where V is one of the vector mesons ρ, ω, φ, J/ψ. We will investigate the situation where the final state positron enters the ZEUS main detector, which indicates that a violent reaction has taken place between the initial state particles, but nevertheless the proton does not break up. The violence with which the positron is scattered characterises the reaction as a Deep Inelastic Scattering (DIS), the fact that the proton does not break up characterises the reaction as diffractive which explains the title of the thesis. Both DIS and diffractive physics will be defined and discussed in the context of this thesis. (orig./WL)

Baryon and meson phenomenology in the extended Linear Sigma Model

Energy Technology Data Exchange (ETDEWEB)

Giacosa, Francesco; Habersetzer, Anja; Teilab, Khaled; Eshraim, Walaa; Divotgey, Florian; Olbrich, Lisa; Gallas, Susanna; Wolkanowski, Thomas; Janowski, Stanislaus; Heinz, Achim; Deinet, Werner; Rischke, Dirk H. [Institute for Theoretical Physics, J. W. Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Kovacs, Peter; Wolf, Gyuri [Institute for Particle and Nuclear Physics, Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525 Budapest (Hungary); Parganlija, Denis [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna (Austria)

2014-07-01

The vacuum phenomenology obtained within the so-called extended Linear Sigma Model (eLSM) is presented. The eLSM Lagrangian is constructed by including from the very beginning vector and axial-vector d.o.f., and by requiring dilatation invariance and chiral symmetry. After a general introduction of the approach, particular attention is devoted to the latest results. In the mesonic sector the strong decays of the scalar and the pseudoscalar glueballs, the weak decays of the tau lepton into vector and axial-vector mesons, and the description of masses and decays of charmed mesons are shown. In the baryonic sector the omega production in proton-proton scattering and the inclusion of baryons with strangeness are described.

Ratios of Vector and Pseudoscalar B Meson Decay Constants in the Light-Cone Quark Model

Science.gov (United States)

Dhiman, Nisha; Dahiya, Harleen

2018-05-01

We study the decay constants of pseudoscalar and vector B meson in the framework of light-cone quark model. We apply the variational method to the relativistic Hamiltonian with the Gaussian-type trial wave function to obtain the values of β (scale parameter). Then with the help of known values of constituent quark masses, we obtain the numerical results for the decay constants f_P and f_V, respectively. We compare our numerical results with the existing experimental data.

Gauge Theories of Vector Particles

Science.gov (United States)

Glashow, S. L.; Gell-Mann, M.

1961-04-24

The possibility of generalizing the Yang-Mills trick is examined. Thus we seek theories of vector bosons invariant under continuous groups of coordinate-dependent linear transformations. All such theories may be expressed as superpositions of certain "simple" theories; we show that each "simple theory is associated with a simple Lie algebra. We may introduce mass terms for the vector bosons at the price of destroying the gauge-invariance for coordinate-dependent gauge functions. The theories corresponding to three particular simple Lie algebras - those which admit precisely two commuting quantum numbers - are examined in some detail as examples. One of them might play a role in the physics of the strong interactions if there is an underlying super-symmetry, transcending charge independence, that is badly broken. The intermediate vector boson theory of weak interactions is discussed also. The so-called "schizon" model cannot be made to conform to the requirements of partial gauge-invariance.

Vector mesons in strongly interacting matter

Indian Academy of Sciences (India)

E-mail: volker.metag@exp2.physik.uni-giessen.de. Abstract. .... constraints on hadronic spectral functions but cannot predict their detailed shape. Hadronic ..... nuclear medium, despite a cut on low momentum ω-mesons: pω ≤ 500 MeV/c. A.

Some heavy vector and tensor meson decay constants in light-front quark model

Energy Technology Data Exchange (ETDEWEB)

Geng, Chao-Qiang [Chongqing Jiaotong University, College of Materials Science and Engineering, Chongqing (China); National Tsing Hua University, Department of Physics, Hsinchu (China); National Center for Theoretical Sciences, Physics Division, Hsinchu (China); Lih, Chong-Chung [National Center for Theoretical Sciences, Physics Division, Hsinchu (China); Shu-Zen College of Medicine and Management, Department of Optometry, Kaohsiung Hsien (China); Xia, Chuanhui [Chongqing Jiaotong University, College of Materials Science and Engineering, Chongqing (China)

2016-06-15

We study the decay constants (f{sub M}) of the heavy vector (D{sup *}, D{sub s}{sup *}, B{sup *}, B{sub s}{sup *}, B{sub c}{sup *}) and tensor (D{sub 2}{sup *}, D{sub s2}{sup *}, B{sub 2}{sup *}, B{sub s2}{sup *}) mesons in the light-front quarkmodel.With the known pseudoscalar meson decay constants of f{sub D}, f{sub Ds}, f{sub B}, f{sub Bs}, and f{sub Bc} as the input parameters to determine the light-front meson wave functions, we obtain f{sub D{sup *},D{sub s{sup *}B{sup *}B{sub s{sup *},B{sub c{sup *}}}}} = (252.0{sub -11.6}{sup +13.8}, 318.3{sub -12.6}{sup +15.3}, 201.9{sub -41.4}{sup +43.2}, 244.2 ± 7.0, 473.4 ± 18.2) and (264.9{sub -9.5}{sup +10.2}, 330.9{sub -9.0}{sup +9.9}, 220.2{sub -46.2}{sup +49.1}, 265.7 ± 8.0, 487.6 ± 19.2) MeV with Gaussian and power-law wave functions, respectively, while we have f{sub D{sub 2{sup *},D{sub s{sub 2{sup *}B{sub 2{sup *}B{sub s{sub 2{sup *}}}}}}}} = (143.6{sub -21.8}{sup +24.9}, 209.5{sub -24.2}{sup +29.1}, 80.9{sub -27.7}{sup +33.8}, 109.7{sub -15.0}{sup +15.7}) MeV with only Gaussian wave functions. (orig.)

Probing the gluon density of the proton in the exclusive photoproduction of vector mesons at the LHC: a phenomenological analysis

Energy Technology Data Exchange (ETDEWEB)

Goncalves, V.P. [Lund University, Department of Astronomy and Theoretical Physics, Lund (Sweden); Universidade Federal de Pelotas, Instituto de Fisica e Matematica, Pelotas, RS (Brazil); Martins, L.A.S.; Sauter, W.K. [Universidade Federal de Pelotas, Instituto de Fisica e Matematica, Pelotas, RS (Brazil)

2016-02-15

The current uncertainty on the gluon density extracted from the global parton analysis is large in the kinematical range of small values of the Bjorken-x variable and low values of the hard scale Q{sup 2}. An alternative to reduces this uncertainty is the analysis of the exclusive vector meson photoproduction in photon-hadron and hadron-hadron collisions. This process offers a unique opportunity to constrain the gluon density of the proton, since its cross section is proportional to the gluon density squared. In this paper we consider current parametrisations for the gluon distribution and estimate the exclusive vector meson photoproduction cross section at HERA and LHC using the leading logarithmic formalism. We perform a fit of the normalisation of the γh cross section and the value of the hard scale for the process and demonstrate that the current LHCb experimental data are better described by models that assume a slow increasing of the gluon distribution at small x and low Q{sup 2}. (orig.)

Study of Muon Pairs and Vector Mesons Produced in High Energy Pb-Pb Interactions

CERN Multimedia

Karavicheva, T; Atayan, M; Bordalo, P; Constans, N P; Gulkanyan, H; Kluberg, L

2002-01-01

%NA50 %title\\\\ \\\\The experiment studies dimuons produced in Pb-Pb and p-A collisions, at nucleon-nucleon c.m. energies of $ \\sqrt{s} $ = 18 and 30 GeV respectively. The setup accepts dimuons in a kinematical range roughly defined as $0.1$ $1 GeV/c$, and stands maximal luminosity (5~10$^{7}$~Pb ions and 10$^7$ interactions per burst). The physics includes signals which probe QGP (Quark-Gluon Plasma), namely the $\\phi$, J/$\\psi$ and $\\psi^\\prime$ vector mesons and thermal dimuons, and reference signals, namely the (unseparated) $\\rho$ and $\\omega$ mesons, and Drell-Yan dimuons. The experiment is a continuation, with improved means, of NA38, and expands its study of {\\it charmonium suppression} and {\\it strangeness enhancement}.\\\\ \\\\The muons are measured in the former NA10 spectrometer, which is shielded from the hot target region by a beam stopper and absorber wall. The muons traverse 5~m of BeO and C. The impact parameter is determined by a Zero Degree Calorimeter (Ta with silica fibres). Energy dissipation ...

HQE parameters from unquenched lattice data on pseudoscalar and vector heavy-light meson masses

Science.gov (United States)

Gambino, Paolo; Melis, Aurora; Simula, Silvano

2018-03-01

We present a new lattice determination of some of the parameters appearing both in the Operator Product Expansion (OPE) analysis of the inclusive semileptonic B-meson decays and in the Heavy Quark Expansion (HQE) of the pseudoscalar (PS) and vector (V) heavy-light meson masses. We perform a lattice QCD (LQCD) computation of PS and V heavy-light meson masses for heavy-quark masses mh in the range from mcphys to ≃ 4mbphys. We employed the Nf = 2 + 1 + 1 gauge configurations of the European Twisted Mass Collaboration (ETMC) at three values of the lattice spacing a ≃ (0.062,0.082,0.089) fm with pion masses in the range Mπ ≃ (210 - 450) MeV. The heavy-quark mass is simulated directly on the lattice up to ≃ 3mcphys. The interpolation to the physical mbphys is performed using the ETMC ratio method and adopting the kinetic mass scheme. We obtain mbkin (1 GeV) = 4.61(20) GeV (m̅b(m̅b) = 4.26(18) GeV in the MS scheme). The lattice data are analyzed in terms of the HQE and the matrix elements of dimension-4 and dimension-5 operators are extracted with good precision, namely: Λ¯ = 0.552(26) GeV, μπ2 = 0.321(32) GeV2 and μG2(mb) = 0.253(25)GeV2. The data also allow for an estimate of the dimension-6 operator matrix elements.

Mesonic effects in nuclear physics

International Nuclear Information System (INIS)

Johnson, M.

1978-01-01

The relation between mesons and nucleons and the properties of nuclear matter, as presently understood, is considered in these lectures. Feynman diagrams, meson theoretical nucleon-nucleon interactions, mesonic components in nuclear wave functions, direct observation of mesonic components in NN scattering above the pion production threshold, nuclear matter theory, and pion condensation are treated. 120 references

Vector meson production in the final state K+K-π+π- photon-photon collisions

International Nuclear Information System (INIS)

ALthoff, M.; Braunschweig, W.; Gerhards, R.; Kirschfink, J.F.; Martyn, H.U.; Rosskamp, P.; Wallraff, W.; Bowler, M.G.; Bull, P.; Cashmore, R.J.; Dauncey, P.; Devenish, R.; Heath, G.; Mellor, D.J.; Ratoff, P.; Baranko, G.; Caldwell, A.; Cherney, M.; Izen, J.M.; Ritz, S.; Strom, D.; Takashima, M.; Wicklund, E.; Wu Saulan; Zobernig, G.; Bernardi, E.; Eisenberg, Y.; Eskresy, A.; Gather, K.; Hultschig, H.; Joos, P.; Klima, B.; Kowalski, H.; Ladage, A.; Loehr, B.; Maettig, P.; Notz, D.; Revel, D.; Ronat, E.; Trines, D.; Tymieniecka, R.; Walcak, R.; Wolf, G.; Zeuner, W.S.

1986-03-01

Vector meson production is studied in the reaction γγ -> K + K - π + π - . A clear PHI(1020) signal is seen in the K + K - mass distribution and a Ksup(*0)(890) signal is visible in the Ksup(+-)πsup(-+) one. Both do not seem to be strongly correlated with quasi two body final states. Cross sections for the processes γγ -> K + K - π + π - , γγ -> PHIπ + π - , γγ -> Ksup(*0)Ksup(+-)πsup(-+) and upper limits for the production of PHIrho, PHIPHI and Ksup(*0)Ksup(*0) are given as function of the invariant γγ mass. (orig.)

Problems of the π meson-nucleus interaction theory

International Nuclear Information System (INIS)

Kopaleishvili, T.I.

1984-01-01

The theory of multiple scattering as applied to PI-meson scattering on nuclei is outlined on the base of optical potential method: first in neglecting the real absorption of a pion by a nucleus and then for the case when this effect is taken into account. The pion interaction with a deuteron is considered both neglecting the pion absorption channel (the relativisitic problem of three bodies) and with account of the absorption channels and pion emission (in this case the problem is solved within the frames of the channel coupling theory for the pion-two nucleus system and the system of two nucleons). Approximate or model solutions to the problem of elastic pion-nuclear scattering primarily in the range of (3.3)-resonance are presented. The formulated theory permits to uniquely describe the observed processes caused by the strong pion interaction with a two-nucleon system

Hadron mass spectrum in a lattice gauge theory

International Nuclear Information System (INIS)

Seo, Koichi

1978-01-01

We perform the strong coupling expansion in a lattice gauge theory and obtain the hadron mass spectrum. We develop a theory in the Hamiltonian formalism following Kogut and Susskind, but our treatment of quark fields is quite different from theirs. Thus our results largely differ from theirs. In our model and approximation, the pseudoscalar mesons have the same mass as the vectors. The baryon decuplet and the octet are also degenerate. The excited meson states are studied in detail. (auth.)

Quarks and mesons in nuclei

International Nuclear Information System (INIS)

Rho, M.

1981-01-01

Quantum chromodynamics is believed to be candidate theory for the strong interactions and contains as its ingredients spinor quark fields and vector gluons, none of which can perhaps be ever liberated and detected in laboratories. A nucleus consists of nucleons bound by nuclear force which are however separately observable and which seem to preserve their identities even under extreme conditions. An intriguing question is: when compressed to high densities or heated to high temperature, at what point does a nuclear matter cease to be describable in terms of nucleon and meson degrees of freedom, but become a plasma of quarks and gluons; and how does this transition occur. This is not an idle question. If quarks and gluons are never to be observed isolated, then it may be that at low energies (or at low densities) they are not the right variables to do physics with. Instead hadrons must be. On the other hand, asymptotic freedom - the unique property of non-abelian gauge theories to which QCD belongs that quark-gluon and gluon-gluon interactions get weaker at short distances - tells us that at some large matter density the matter must necessarily be in the form of quark gas interacting only weakly. This means that a change in degrees of freedom must take place. We would like to know where this occurs and how. In this talk, I would like to address to this question by discussing first the large success we have had in understanding the role that mesons play in finite nuclei and nuclear matter and then attempting to correlate nucleon and meson degrees of freedom to quark-gluon degrees of freedom. In my opinion we are now at a stage where we feel fairly confident in our understanding of nucleon-meson structure of nuclei and nuclear matter and any further progress in deeper understanding of nuclear dynamics - and strong interactions - must come from QCD or its effective version, bags or strings. (orig.)

Parity violating nuclear force by meson mixing

International Nuclear Information System (INIS)

Iqbal, M.J.; Niskanen, J.A.

1990-01-01

We study a mechanism for parity violation in the two nucleon meson-exchange interaction by way of the mixing of mesons of opposite parities. This mixing arises from parity violating W ± and Z exchange between the q bar q pair in the meson. Numerically its effect turns out to be as important as vector meson exchange with a weak meson-nucleon vertex and may partly be used to model this vertex. The calculation is performed using both the standard Born approximation adding the amplitude phases by Watson's theorem and also using the exact correlated two-nucleon wave functions. The effect of correlations and form factors is found to be crucially important at intermediate energies

Investigating the impact of the gluon saturation effects on the momentum transfer distributions for the exclusive vector meson photoproduction in hadronic collisions

Directory of Open Access Journals (Sweden)

V.P. Gonçalves

2017-05-01

Full Text Available The exclusive vector meson production cross section is one of the most promising observables to probe the high energy regime of the QCD dynamics. In particular, the squared momentum transfer (t distributions are an important source of information about the spatial distribution of the gluons in the hadron and about fluctuations of the color fields. In this paper we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the t-spectrum measured in exclusive ρ, ϕ and J/Ψ photoproduction in pp and PbPb collisions at the LHC. We compute the differential cross sections taking into account gluon saturation effects and compare the predictions with those obtained in the linear regime of the QCD dynamics. Our results show that gluon saturation suppresses the magnitude of the cross sections and shifts the position of the dips towards smaller values of t.

Scale-chiral symmetry, ω meson, and dense baryonic matter

Science.gov (United States)

Ma, Yong-Liang; Rho, Mannque

2018-05-01

It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension (|γG2| ) of the gluon field strength tensor squared (G2 ) that represents the quantum trace anomaly should be 1.0 ≲|γG2|≲3.5 . The magnitude of |γG2| estimated here will be useful for studying hadron and nuclear physics based on the scale-chiral effective theory. More significantly, that the dilaton limit fixed point can be arrived at with γG2≠0 at some high density signals that scale symmetry can arise in dense medium as an "emergent" symmetry.

Decays of open charmed mesons in the extended Linear Sigma Model

Directory of Open Access Journals (Sweden)

Eshraim Walaa I.

2014-01-01

Full Text Available We enlarge the so-called extended linear Sigma model (eLSM by including the charm quark according to the global U(4r × U(4l chiral symmetry. In the eLSM, besides scalar and pseudoscalar mesons, also vector and axial-vector mesons are present. Almost all the parameters of the model were fixed in a previous study of mesons below 2 GeV. In the extension to the four-flavor case, only three additional parameters (all of them related to the bare mass of the charm quark appear.We compute the (OZI dominant strong decays of open charmed mesons. The results are compatible with the experimental data, although the theoretical uncertainties are still large.

Spin O decay angular distribution for interfering mesons in electroproduction

Energy Technology Data Exchange (ETDEWEB)

Funsten, H.; Gilfoyle, G.

1994-04-01

Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.

S-wave spectroscopy and Hyperne splitting of Bc meson

International Nuclear Information System (INIS)

Shah, Manan; Bhavsar, Tanvi; Vinodkumar, P.C.

2017-01-01

B c meson is the only heavy meson with two open flavours. This system is also interesting because they cannot annihilate into gluons. The mass spectra and hyperfine splitting of the B c meson are investigated in the Dirac framework with the help of linear + constant potential. The spin-spin interactions are also included in the calculation of the pseudoscalar and vector meson masses. Our computed result for the B c meson are in very good agreement with experimental results as well as other available theoretical result. Decay properties are also interesting because it is expected that decay of B c meson occur in to neutral meson. We hope our theoretical results are helpful for future experimental observations

A unitarized meson model including color Coulomb interaction

International Nuclear Information System (INIS)

Metzger, Kees.

1990-01-01

Ch. 1 gives a general introduction into the problem field of the thesis. It discusses in how far the internal structure of mesons is understood theoretically and which models exist. It discusses from a phenomenological point of view the problem of confinement indicates how quark models of mesons may provide insight in this phenomenon. In ch. 2 the formal theory of scattering in a system with confinement is given. It is shown how a coupled channel (CC) description and the work of other authors fit into this general framework. Explicit examples and arguments are given to support the CC treatment of such a system. In ch. 3 the full coupled-channel model as is employed in this thesis is presented. On the basis of arguments from the former chapters and the observed regularities in the experimental data, the choices underlying the model are supported. In this model confinement is described with a mass-dependent harmonic-oscillator potential and the presence of open (meson-meson) channels plays an essential role. In ch. 4 the unitarized model is applied to light scalar meson resonances. In this regime the contribution of the open channels is considerable. It is demonstrated that the model parameters as used for the description of the pseudo-scalar and vector mesons, unchanged can be used for the description of these mesons. Ch. 5 treats the color-Coulomb interaction. There the effect of the Coulomb interaction is studied in simple models without decay. The results of incorporating the color-Coulomb interaction into the full CC model are given in ch.6. Ch. 7 discusses the results of the previous chapters and the present status of the model. (author). 182 refs.; 16 figs.; 33 tabs

QGP thermodynamics and Meson spectroscopy with AdS/CFT

Science.gov (United States)

Erdmenger, J.; Kaminski, M.; Rust, F.

In this talk we present applications of the AdS/CFT correspondence to strongly coupled sys- tems at finite temperature and particle density. The model we investigate contains adjoint matter described by the gauge multiplet of N = 4, as well as fundamental matter given by the hyper- multiplet of N = 2 Super Yang-Mills theory. In some aspects these systems can be thought of as models for the quark-gluon plasma. In the first part we review some properties of meson spectra obtained from these holographic models. We discuss the implications of finite temperature and particle density in these string- theory motivated setups. In particular, we find a broadening of the vector meson peaks in the relevant spectral function at finite density. However, we do not observe a movement of the reso- nances to lower frequencies. Moreover, we analyze the effects of strong coupling on heavy meson diffusion in medium. To do so we make use of an effective model with dipole interaction, which is valid for heavy quarks at arbitrary coupling strength. We calculate the momentum broadening — normalized to the in-medium mass shift — and compare the large ’t Hooft coupling AdS/CFT result with a perturbative result for weak coupling. We find that the momentum broadening is reduced at large ’t Hooft coupling, leading to increased relaxation time.

Semileptonic decays of the Bc meson

International Nuclear Information System (INIS)

Barik, N.; Naimuddin, Sk.; Dash, P. C.; Kar, Susmita

2009-01-01

We study the semileptonic transitions B c →η c ,J/Ψ,D,D*,B,B*,B s ,B s * in the leading order in the framework of a relativistic independent quark model based on a confining potential in the equally mixed scalar-vector harmonic form. We compute relevant weak form factors as overlap integrals of the meson-wave functions obtained in the relativistic independent quark model in the whole accessible kinematical range. We predict that the semileptonic transitions of the B c meson are mostly dominated by two Cabibbo-Kobayashi-Maskawa (CKM)-favored modes, B c →B s (B s *)eν, contributing about 77% of the total decay width, and its decays to vector meson final states take place in the predominantly transverse mode. Our predicted values for the total decay rates, branching ratios, polarization ratios, the forward-backward asymmetry factor, etc., are broadly in agreement with other model predictions.

Aspects of meson-baryon scattering in three- and two-flavor chiral perturbation theory

International Nuclear Information System (INIS)

Mai, Maxim; Bruns, Peter C.; Kubis, Bastian; Meissner, Ulf-G.

2009-01-01

We analyze meson-baryon scattering lengths in the framework of covariant baryon chiral perturbation theory at leading one-loop order. We compute the complete set of matching relations between the dimension-two low-energy constants in the two- and three-flavor formulations of the theory. We derive new two-flavor low-energy theorems for pion-hyperon scattering that can be tested in lattice simulations.

Asymptotic energy scale factors for pseudoscalar meson scattering and charmed meson couplings

International Nuclear Information System (INIS)

Thews, R.L.

1977-01-01

Energy scale factors ν 0 for PP → PP scattering amplitudes are related via absence of exotic resonances of ratios of tensor to vector coupling strengths. These same ratios are extracted from FESR's for non-exotic reactions. The scale factors obtained are all of the order of 1.0 GeV 2 or less, indepedent of quantum numbers. This contradicts the expectations of dual amplitudes in which ν 0 =1/α', and trajectory slopes are smaller for charmed mesons. Decay widths for tensor mesons are predicted. An observed SU(3) violation for the ratio A 2 → KantiK/K** → Kπ is shown to be consistent with the FESR results. Charmed meson decays are predicted to be factors of 2 to 3 larger than those predicted by SU(4). (author)

Exclusive vector meson production in muon-nucleus scattering

International Nuclear Information System (INIS)

Fang, G.Y.

1994-02-01

Preliminary results on the cross section ratios of exclusive incoherent ρ 0 and φ meson production off deuterium, carbon, calcium, and lead to that off hydrogen and coherent ρ 0 and φ meson production off calcium and lead to that off carbon in deep-inelastic muon-nucleon and muon-nucleus scattering are reported. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam. The mean beam energy was 470 GeV. Increases in the cross section ratios are seen in both the elastic and quasi-elastic production as the four-momentum squared of the virtual photon increases. The results support the idea of color transparency

Systematics of strong nuclear amplification of gluon saturation from exclusive vector meson production in high energy electron-nucleus collisions

Science.gov (United States)

Mäntysaari, Heikki; Venugopalan, Raju

2018-06-01

We show that gluon saturation gives rise to a strong modification of the scaling in both the nuclear mass number A and the virtuality Q2 of the vector meson production cross-section in exclusive deep-inelastic scattering off nuclei. We present qualitative analytic expressions for how the scaling exponents are modified as well as quantitative predictions that can be tested at an Electron-Ion Collider.

The 'silent' phase transition in mesonic bags and lattice theory

International Nuclear Information System (INIS)

Dey, J.; Dey, M.; Araujo Junior, C.F. de; Tomio, L.

1993-10-01

It is shown that even the simple bag model is able to reproduce the lattice result for the masses and the sound velocity, at finite temperature, T, suggests that the transition point depends on the nature of the meson. It would be interesting to check the last conclusion in present day finite temperature lattice theory, since different transition points seem to be indicated by particle emission T in heavy ion reactions. (author)

The interpretation of the iota meson

International Nuclear Information System (INIS)

Frank, M.

1985-01-01

The authors analyze the iota (1440) meson in a non-relativistic quark model. The authors review the experimental data, then attempt to incorporate it in the mass spectrum and radiative decays of the low-lying pseudoscalar and vector mesons. Correlating these results with production decay rates from J/psi and the radiative decays of iota, the authors conclude that the iota has to be interpreted as having a strong gluonium component

Multistrange Meson-Baryon Dynamics and Resonance Generation

Science.gov (United States)

Khemchandani, K. P.; Martínez Torres, A.; Hosaka, A.; Nagahiro, H.; Navarra, F. S.; Nielsen, M.

2018-05-01

In this talk I review our recent studies on meson-baryon systems with strangeness - 1 and - 2. The motivation of our works is to find resonances generated as a consequence of coupled channel meson-baryon interactions. The coupled channels are all meson-baryon systems formed by combining a pseudoscalar or a vector meson with an octet baryon such that the system has the strange quantum number equal to - 1 or - 2. The lowest order meson-baryon interaction amplitudes are obtained from Lagrangians based on the chiral and the hidden local symmetries related to the vector mesons working as the gauge bosons. These lowest order amplitudes are used as an input to solve the Bethe-Salpeter equation and a search for poles is made in the resulting amplitudes, in the complex plane. In case of systems with strangeness - 1, we find evidence for the existence of some hyperons such as: Λ(2000), Σ(1750), Σ(1940), Σ(2000). More recently, in the study of strangeness - 2 systems we have found two narrow resonances which can be related to Ξ (1690) and Ξ(2120). In this latter work, we have obtained the lowest order amplitudes relativistically as well as in the nonrelativistic approximation to solve the scattering equations. We find that the existence of the poles in the complex plane does not get affected by the computation of the scattering equation with the lowest order amplitudes obtained in the nonrelativistic approximation.

Measurement of vector boson plus D*(2010)+ meson production in p ¯p collisions at √{s }=1.96 TeV

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.; 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.; 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.; 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.; 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.; 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.; Denis, R. St.; 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.; 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

2016-03-01

A measurement of vector boson (V ) production in conjunction with a D*(2010)+meson is presented. Using a data sample corresponding to 9.7 fb-1 of proton-antiproton collisions at center-of-mass energy √{s }=1.96 TeV produced by the Fermilab Tevatron, we reconstruct V +D*+ samples with the CDF II detector. The D*+ is fully reconstructed in the D*(2010)+→D0(→K-π+)π+ decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections σ (W +D*)/σ (W )=[1.75 ±0.13 (stat ) ±0.09 (stat ) ]% and σ (Z +D*)/σ (Z )=[1.5 ±0.4 (stat ) ±0.2 (stat ) ]% and perform a differential measurement of d σ (W +D*)/d pT(D*). Event properties are utilized to determine the fraction of V +D*(2010)+ events originating from different production processes. The results are in agreement with the predictions obtained with the pythia program, limiting possible contribution from non-standard-model physics processes.

Radiative decay of light and heavy mesons

International Nuclear Information System (INIS)

Barik, N.; Dash, P.C.

1994-01-01

The M1 transition among the vector (V) and pseudoscalar (P) mesons in the light and heavy flavor sectors has been investigated in a potential model of independent quarks. Going beyond the static approximation, to add some momentum dependence due to the recoil effect in a more realistic calculation, we find an improvement in the results for the radiative decay of light flavored mesons. However, our prediction on the decay rates for the mesons (D * and B * ) in the heavy flavor sector remains unaffected and compares well with those of other model calculations

D* and B* mesons in strange hadronic medium at finite temperature

International Nuclear Information System (INIS)

Chhabra, R.; Kumar, A.

2016-01-01

We calculate the effect of density and temperature of isospin symmetric strange medium on the shift in masses and decay constants of vector D and B mesons using chiral SU(3) model and QCD sum rule approach. In the present investigation the values of quark and gluon condensates are calculated from the chiral SU(3) model and these condensates are further used as input in the QCD Sum rule framework to calculate the in-medium masses and decay constants of vector D and B mesons. These in medium properties of vector D and B mesons may be helpful to understand the experimental observables of the experiments like CBM and PANDA under FAIR project at GSI, Germany. The results which are observed in the present work are also compared with previous predictions. (authors)

Inclusive Production of the $\\omega(782)$ Vector Meson in Hadronic Decays of the Z

CERN Document Server

Beddall, A

1995-01-01

The inclusive production of the omega(782) vector meson in hadronic Z decays is studied and compared to model predictions. The analysis is based on 1,005,535 hadronic Z decays recorded by the ALEPH detector in the 1992 and 1993 running periods of LEP. Decays of the omega -> pi^+ pi^- pi^0 are reconstructed for x_p > 0.05, where x_p = p/p_{beam}. For this momentum range the omega production rate is measured to be 0.633 +- 0.025(stat) +- 0.056(sys) per event. An extrapolation to x_p = 0 yields a total production rate of 1.061 +- 0.041(stat) +- 0.093(sys) +- 0.042(extrap) per event.

Equivalence of meson scattering amplitudes in strong coupling lattice and flat space string theory

Directory of Open Access Journals (Sweden)

Adi Armoni

2018-03-01

Full Text Available We consider meson scattering in the framework of the lattice strong coupling expansion. In particular we derive an expression for the 4-point function of meson operators in the planar limit of scalar Chromodynamics. Interestingly, in the naive continuum limit the expression coincides with an independently known result, that of the worldline formalism. Moreover, it was argued by Makeenko and Olesen that (assuming confinement the resulting scattering amplitude in momentum space is the celebrated expression proposed by Veneziano several decades ago. This motivates us to also use holography in order to argue that the continuum expression for the scattering amplitude is related to the result obtained from flat space string theory. Our results hint that at strong coupling and large-Nc the naive continuum limit of the lattice formalism can be related to a flat space string theory.

Equivalence of meson scattering amplitudes in strong coupling lattice and flat space string theory

Science.gov (United States)

Armoni, Adi; Ireson, Edwin; Vadacchino, Davide

2018-03-01

We consider meson scattering in the framework of the lattice strong coupling expansion. In particular we derive an expression for the 4-point function of meson operators in the planar limit of scalar Chromodynamics. Interestingly, in the naive continuum limit the expression coincides with an independently known result, that of the worldline formalism. Moreover, it was argued by Makeenko and Olesen that (assuming confinement) the resulting scattering amplitude in momentum space is the celebrated expression proposed by Veneziano several decades ago. This motivates us to also use holography in order to argue that the continuum expression for the scattering amplitude is related to the result obtained from flat space string theory. Our results hint that at strong coupling and large-Nc the naive continuum limit of the lattice formalism can be related to a flat space string theory.

Meson masses and decay constants from unquenched lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); McNeile, C. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Michael, C. [Liverpool Univ. (United Kingdom). Theoretical Physics Div., Dept. of Mathematical Sciences; Urbach, C. [Humboldt Univ. Berlin (Germany). Inst. fuer Physik

2009-06-15

We report results for the masses of the flavour non-singlet light 0{sup ++}, 1{sup --}, and 1{sup +-} mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0{sup ++} and 1{sup +-} mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the meson. We test the mass dependence of the KRSF relations. (orig.)

Meson masses and decay constants from unquenched lattice QCD

International Nuclear Information System (INIS)

Jansen, K.; McNeile, C.; Michael, C.; Urbach, C.

2009-06-01

We report results for the masses of the flavour non-singlet light 0 ++ , 1 -- , and 1 +- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0 ++ and 1 +- mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the meson. We test the mass dependence of the KRSF relations. (orig.)

Single meson photoproduction and IR renormalons

International Nuclear Information System (INIS)

Agaev, S.S.

1996-10-01

Single pseudoscalar and vector mesons inclusive photoproduction γh → MX via higher twist mechanism is calculated using the QCD running coupling constant method. It is proved that in the context of this method a higher twist contribution to the photoproduction cross section cannot be normalized in terms of the meson electromagnetic form factor. The structure of infrared renormalon singularities of the higher twist subprocess cross section and the resumed expression (the Borel sum) for it are found. Comparisons are made with earlier results, as well as with leading twist cross section. Phenomenological effects of studied contributions for π, K, ρ-meson photoproduction are discussed. (author). 21 refs, 8 figs

On the vector meson dominate hypothesis and the RA = σLA/σTA value in electron-nucleus deep inelastic scattering

International Nuclear Information System (INIS)

Peng Hongan; Liu Lianshou

1986-01-01

It is argued that the longitudinal part of space-like photon in its Breit frame is unable to transform into vector meson. Starting from this argument and adding a small amount of diquark component into the nucleon structure functions in nuclei, the A dependence of the R A = σ L A /σ T A value observed in electron nucleus DIS by the SLAC Group is explained

Antiproton-proton annihilation into light neutral meson pairs within an effective meson theory

Science.gov (United States)

Wang, Ying; Bystritskiy, Yury M.; Ahmadov, Azad I.; Tomasi-Gustafsson, Egle

2017-08-01

Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in s , t , and u channels, is applied here to π0π0 production. Form factors with logarithmic s and t (u ) dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for π0η and η η production in the same energy range. A good agreement is generally obtained with all existing data.

Spectroscopy of SU(4) composite Higgs theory with two distinct fermion representations

Science.gov (United States)

Ayyar, Venkitesh; DeGrand, Thomas; Golterman, Maarten; Hackett, Daniel C.; Jay, William I.; Neil, Ethan T.; Shamir, Yigal; Svetitsky, Benjamin

2018-04-01

We have simulated the SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. Such theories arise naturally in the context of composite Higgs models that include a partially composite top quark. We describe the low-lying meson spectrum of the theory and fit the pseudoscalar masses and decay constants to chiral perturbation theory. We infer as well the mass and decay constant of the Goldstone boson corresponding to the nonanomalous U(1) symmetry of the model. Our results are broadly consistent with large-Nc scaling and vector-meson dominance.

Violation of vector dominance in the vector manifestation

International Nuclear Information System (INIS)

Sasaki, Chihiro

2003-01-01

The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the hidden local symmetry (HLS) Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson. (author)

Vector supersymmetry in topological field theories

International Nuclear Information System (INIS)

Gieres, F.; Grimstrup, J.; Pisar, T.; Schweda, M.

2000-01-01

We present a simple derivation of vector supersymmetry transformations for topological field theories of Schwarz- and Witten-type. Our method is similar to the derivation of BRST-transformations from the so-called horizontality conditions or Russian formulae. We show that this procedure reproduces in a concise way the known vector supersymmetry transformations of various topological models and we use it to obtain some new transformations of this type for 4d topological YM-theories in different gauges. (author)

Versatility of field theory motivated nuclear effective Lagrangian approach

International Nuclear Information System (INIS)

Arumugam, P.; Sharma, B.K.; Sahu, P.K.; Patra, S.K.; Sil, Tapas; Centelles, M.; Vinas, X.

2004-01-01

We analyze the results for infinite nuclear and neutron matter using the standard relativistic mean field model and its recent effective field theory motivated generalization. For the first time, we show quantitatively that the inclusion in the effective theory of vector meson self-interactions and scalar-vector cross-interactions explains naturally the recent experimental observations of the softness of the nuclear equation of state, without losing the advantages of the standard relativistic model for finite nuclei

C(1480) meson and electromagnetic processes

International Nuclear Information System (INIS)

Landsberg, L.G.

1992-01-01

Possible processes of production of the vector meson C(1480) → var-phi π, a candidate for exotic states, in electromagnetic processes are considered [photoproduction, e + e - →C(1480) → var-phi π 0 , and the reaction of production of C(1480) in the Coulomb field of a nucleus]. It is shown that coherent Coulomb production of the C(1480) meson allows one to determine the absolute value of BR[C(1480) → var-phi π], which is essential for the interpretation of the nature of this hadron. Possibilities of observing C(1480) mesons in e + e - collisions at the var-phi factory DAΦNE are studied. 27 refs., 12 figs., 1 tab

Temperature, chemical potential and the ρ meson

International Nuclear Information System (INIS)

Roberts, C. D.; Schmidt, S. M.

2000-01-01

Models of QCD must confront nonperturbative phenomena such as confinement, dynamical chiral symmetry breaking (DCSB) and the formation of bound states. In addition, a unified approach should describe the deconfinement and chiral symmetry restoring phase transition exhibited by strongly-interacting matter under extreme conditions of temperature and density. Nonperturbative Dyson-Schwinger equation (DSE) models provide insight into a wide range of zero temperature hadronic phenomena; e.g., non-hadronic electroweak interactions of light- and heavy-mesons, and diverse meson-meson and meson-nucleon form factors. This is the foundation for their application at nonzero-(T, μ). Herein the authors describe the calculation of the reconfinement and chiral symmetry restoring phase boundary, and the medium dependence of ρ-meson properties. They also introduce an extension to describe the time-evolution in the plasma of the quark's scalar and vector self energies based on a Vlasov equation

Gauge structure of neutral-vector field theory. [Massive vector fields, massless limits

Energy Technology Data Exchange (ETDEWEB)

Kubo, R; Yokoyama, [Hiroshima univ., Takehara (Japan). Research Inst. for Theoretical Physics

1975-03-01

General aspects of gauge structure of neutral-vector field theory are investigated from an extended standpoint, where massive vector fields are treated in a form corresponding to the electromagnetic fields in a general gauge formalism reported previously. All results obtained are shown to have unique massless limits. It is shown that a generalized q-number gauge transformation for fields makes the theory invariant in cooperation with a simultaneous transformation for relevant gauge parameters. A method of differentiation with respect to a gauge variable is found to clarify some essential features of the gauge structure. Two possible types of gauge structure also emerge correspondingly to the massless case. A neutral-vector field theory proposed in a preceding paper is included in the present framework as the most preferable case.

Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

Energy Technology Data Exchange (ETDEWEB)

Hilger, Thomas Uwe

2012-04-11

The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Anlaysis of the Effects of the ρ-ω Mixing in ρ and ω Mesons

International Nuclear Information System (INIS)

Kuecuekarslan, A.

2004-01-01

We review the radiative ω→π 0 π 0 γ, ρ→π 0 π 0 γ, ω →π 0 ηγ, ρ→π 0 ηγ, ω→π + π - γ and ρ→π + π - γ, decays in a phenomenological framework in which the contributions of vector meson dominance model, chiral loop, bremsstrahlung, σ-meson and a 0 -meson intermediate state amplitude and the effects of ω-ρ mixing are considered. We conclude that ρ-ω mixing contribution is dominant for ω→ππγ, decays, but for other decays it is relevant in the rest of the decays. Therefore, this mixing should be included in the analysis of the vector meson

Extended vector meson dominance model for the baryon octet electromagnetic form factors

International Nuclear Information System (INIS)

Williams, R.A.; Puckett-Truman, C.

1996-01-01

An unresolved issue in the present understanding of nucleon structure is the effect of hidden strangeness on electromagnetic observables such as G n E (q 2 ). Previously, we have shown that G n E (q 2 ) is sensitive to small φNN couplings. A complementary approach for understanding effects due to strangeness content and the Okubo-Zweig-Iizuka (OZI) rule is to investigate the electromagnetic structure of hyperons. We apply Sakurai close-quote s universality limit of the SU(3) F symmetry relations and a prescription based on the OZI rule to calculate the electromagnetic form factors of the baryon octet states (p,n,Λ,Σ + ,Σ 0 ,Σ - ,Ξ 0 ,Ξ - ) within the framework of an extended vector meson dominance model. To provide additional motivation for experimental investigation, we discuss the possibility of extracting the ratio G M Λ (q 2 )/G M ΣΛ (q 2 ) from the Λ/Σ polarization ratio in kaon electroproduction experiments. copyright 1996 The American Physical Society

Decay Constants of B and D Mesons from Non-pertubatively Improved Lattice QCD

Energy Technology Data Exchange (ETDEWEB)

K.C. Bowler; L. Del Debbio; J.M. Flynn; G.N, Lacagnina; V.I. Lesk; C.M. Maynard; D.G. Richards

2000-07-01

The decay constants of B and D mesons are computed in quenched lattice QCD at two different values of the coupling. The action and operators are ? (a) improved with non-perturbative coefficients where available. The results and systematic errors are discussed in detail. Results for vector decay constants, flavour symmetry breaking ratios of decay constants, the pseudoscalar-vector mass splitting and D meson masses are also presented.

Meson spectroscopy at the Serpukhov accelerator

International Nuclear Information System (INIS)

Prokoshkin, Yu.D.

1987-01-01

At present meson spectroscopy is a dominating direction of experimental studies at the IHEP accelerator. The main attention is paid to the search and study of exotic meson states. This report presents some new results obtained recently at the IHEP accelerator. First, observation is made of a narrow 1750 MeV meson decays into ηη. Above |t| ∼ 0.2 (GeV-c) 2 (t: a square of 4-momentum transferred to a neutron), a clear narrow peak appears in Mηη mass spectrum at a mass of 1750 MeV. Second, 2.22 GeV narrow meson decaying into η'η is described. At present only premature conclusions have been obtained in this area and the situation with ζ is not clear. Third, a study is made on new exotic tensor meson χ(1810) decaying into 4π deg and ηη channels. The decay M deg → 4π deg is a very promissing instrument in search for exotic mesons. Next, G(1590)-meson as a scalar glueball is discussed. BR(G → 4π deg) has a large value, an independent evidence of the exotic nature of G(1590)-meson. Experimental data obtained on all essential decay channels of G(1590)-meson allows to give a selfconsistent description of its production and decay as the scalar glueball, a particle with the dominating gluon component. The final two parts deal with exotic vector meson C(1480) decaying into ψπ deg and observation of D(1285) → ψγ decay. (Nogami, K.)

Compact stars in vector-tensor-Horndeski theory of gravity

Energy Technology Data Exchange (ETDEWEB)

Momeni, Davood; Myrzakulov, Kairat; Myrzakulov, Ratbay [Eurasian National University, Department of General and Theoretical Physics, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada)

2017-01-15

In this paper, we will analyze a theory of modified gravity, in which the field content of general relativity will be increased to include a vector field. We will use the Horndeski formalism to non-minimally couple this vector field to the metric. As we will be using the Horndeski formalism, this theory will not contain Ostrogradsky ghost degree of freedom. We will analyze compact stars using this vector-tensor-Horndeski theory. (orig.)

Semileptonic decays of the B{sub c} meson

Energy Technology Data Exchange (ETDEWEB)

Barik, N [Department of Physics, Utkal University, Bhubaneswar-751004 (India); Naimuddin, Sk [Department of Physics, Maharishi College of Natural Law, Bhubaneswar-751007 (India); Dash, P C [Department of Physics, Prananath Autonomous College, Khurda-752057 (India); Kar, Susmita [Department of Physics, North Orissa University, Baripada-757003 (India)

2009-10-01

We study the semileptonic transitions B{sub c}{yields}{eta}{sub c},J/{psi},D,D*,B,B*,B{sub s},B{sub s}* in the leading order in the framework of a relativistic independent quark model based on a confining potential in the equally mixed scalar-vector harmonic form. We compute relevant weak form factors as overlap integrals of the meson-wave functions obtained in the relativistic independent quark model in the whole accessible kinematical range. We predict that the semileptonic transitions of the B{sub c} meson are mostly dominated by two Cabibbo-Kobayashi-Maskawa (CKM)-favored modes, B{sub c}{yields}B{sub s}(B{sub s}*)e{nu}, contributing about 77% of the total decay width, and its decays to vector meson final states take place in the predominantly transverse mode. Our predicted values for the total decay rates, branching ratios, polarization ratios, the forward-backward asymmetry factor, etc., are broadly in agreement with other model predictions.

Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

Science.gov (United States)

Bijnens, Johan; Rössler, Thomas

2015-11-01

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique.

Rapidity resummation for B-meson wave functions

Directory of Open Access Journals (Sweden)

Shen Yue-Long

2014-01-01

Full Text Available Transverse-momentum dependent (TMD hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ζ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B → π transition form factors at large hadronic recoil.

Vector meson production in pp collisions at $\\sqrt{s}=7 TeV$, measured with the ALICE detector

CERN Document Server

De Falco, A

2011-01-01

Vector mesons are key probes of the hot and dense state of strongly interacting matter produced in heavy ion collisions. Their dileptonic decay channel is particularly suitable for these studies, since dileptons have negligible final state interactions in hadronic matter. A preliminary measurement of the $\\phi$ and $\\omega$ differential cross sections was performed by the ALICE experiment in pp collisions at $\\sqrt{s}=7$ TeV, through their decay in muon pairs. The $p_{\\rm T}$ and rapidity regions covered in this analysis are $p_{\\rm T}>1$ GeV$/c$ and $2.5 < y < 4$.

Quasilocal quark models as effective theory of non-perturbative QCD

International Nuclear Information System (INIS)

Andrianov, A.A.

2006-01-01

We consider the Quasilocal Quark Model of NJL type (QNJLM) as effective theory of non-perturbative QCD including scalar (S), pseudo-scalar (P), vector (V) and axial-vector (A) four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as a consequence the composite meson states are generated in all channels. With the help of Operator Product Expansion the appropriate set of Chiral Symmetry Restoration (CSR) Sum Rules in these channels are imposed as matching rules to QCD at intermediate energies. The mass spectrum and some decay constants for ground and excited meson states are calculated

Vector-vector production in photon-photon interactions

International Nuclear Information System (INIS)

Ronan, M.T.

1988-01-01

Measurements of exclusive untagged /rho/ 0 /rho/ 0 , /rho//phi/, K/sup *//bar K//sup */, and /rho/ω production and tagged /rho/ 0 /rho/ 0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs

A non-linear theory of strong interactions

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

A non-linear theory of mesons, nucleons and hyperons is proposed. The three independent fields of the usual symmetrical pseudo-scalar pion field are replaced by the three directions of a four-component field vector of constant length, conceived in an Euclidean four-dimensional isotopic spin space. This length provides the universal scaling factor, all other constants being dimensionless; the mass of the meson field is generated by a φ 4 term; this destroys the continuous rotation group in the iso-space, leaving a 'cubic' symmetry group. Classification of states by this group introduces quantum numbers corresponding to isotopic spin and to 'strangeness'; one consequences is that, at least in elementary interactions, charge is only conserved module 4. Furthermore, particle states have not a well-defined parity, but parity is effectively conserved for meson-nucleon interactions. A simplified model, using only two dimensions of space and iso-space, is considered further; the non-linear meson field has solutions with particle character, and an indication is given of the way in which the particle field variables might be introduced as collective co-ordinates describing the dynamics of these particular solutions of the meson field equations, suggesting a unified theory based on the meson field alone. (author). 7 refs

Support vector machines optimization based theory, algorithms, and extensions

CERN Document Server

Deng, Naiyang; Zhang, Chunhua

2013-01-01

Support Vector Machines: Optimization Based Theory, Algorithms, and Extensions presents an accessible treatment of the two main components of support vector machines (SVMs)-classification problems and regression problems. The book emphasizes the close connection between optimization theory and SVMs since optimization is one of the pillars on which SVMs are built.The authors share insight on many of their research achievements. They give a precise interpretation of statistical leaning theory for C-support vector classification. They also discuss regularized twi

Radiative decays involving f0(980) and a0(980) and mixing between low and high mass scalar mesons

International Nuclear Information System (INIS)

Teshima, T.; Kitamura, I.; Morisita, N.

2005-01-01

We analyze the experimental data for φ->f 0 (980)γ, φ->a 0 (980)γ, f 0 (980)->γγ and a 0 (980)->γγ decay widths in a framework where f 0 (980) and a 0 (980) are assumed to be mainly qqq-bar q-bar low mass scalar mesons and mixed with qq-bar high mass scalar mesons. Applied the vector meson dominance model (VDM), these decays amplitudes are expressed by coupling parameters B describing the S (qqq-bar q-bar scalar meson)-V (vector meson)-V (vector meson) coupling and B ' describing the S ' (qq-bar scalar meson)-V-V coupling. Adopting the magnitudes for B and B ' as 3∼2.8 GeV -1 and ∼12 GeV -1 , respectively, the mixing angle between a 0 (980) and a 0 (1450) as ∼9 o , and the mixing parameter λ 01 causing the mixing between I=0 qqq-bar q-bar state and qq-bar state as ∼0.24 GeV 2 , we can interpret these experimental data, consistently

Meson spectroscopy, quark mixing and quantum chromodynamics

International Nuclear Information System (INIS)

Filippov, A.T.

1979-01-01

A semiphenomenological theory of mass spectrum for mesons, consisting of a quark-antiquark pair, is presented. Relativistic kinematical effects of the quark mass differences, the SU(3)-symmetry breaking in slopes of the Regge trajectories and in radially excited states are taken into account. The OZI-rule breaking is taken into account by means of the mixing matrix for the quark wave functions, whose form is suggested by the quantum chromodynamics. A simple extrapolation of expression, given by the quantum chromodynamics from the ''asymptotic freedom'' region to the ''infrared slavery'' region is proposed to describe the dependence of the mixing parameters on the meson masses. To calculate masses and mixing angles for pseudoscalar mesons a condition is proposed that the pion mass is minimal. In this situation the eta-meson mass is near the maximal value. The predictions of the theory for masses and mixing angles of the mesons are in good agreement with the experiment

Excited meson radiative transitions from lattice QCD using variationally optimized operators

Energy Technology Data Exchange (ETDEWEB)

Shultz, Christian J. [Old Dominion Univ., Norfolk, VA (United States); Dudek, Jozef J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2015-06-02

We explore the use of 'optimized' operators, designed to interpolate only a single meson eigenstate, in three-point correlation functions with a vector-current insertion. These operators are constructed as linear combinations in a large basis of meson interpolating fields using a variational analysis of matrices of two-point correlation functions. After performing such a determination at both zero and non-zero momentum, we compute three-point functions and are able to study radiative transition matrix elements featuring excited state mesons. The required two- and three-point correlation functions are efficiently computed using the distillation framework in which there is a factorization between quark propagation and operator construction, allowing for a large number of meson operators of definite momentum to be considered. We illustrate the method with a calculation using anisotopic lattices having three flavors of dynamical quark all tuned to the physical strange quark mass, considering form-factors and transitions of pseudoscalar and vector meson excitations. In conclusion, the dependence on photon virtuality for a number of form-factors and transitions is extracted and some discussion of excited-state phenomenology is presented.

Recent results on D meson decays from the MARK III

International Nuclear Information System (INIS)

Coward, D.H.

1985-10-01

The MARK III Collaboration recently completed the analysis of a number of decay modes of charged and neutral D mesons produced in electron-positron collisions near the peak of the psi(3770) resonance at SLAC's SPEAR storage ring. The mesons were produced nearly at rest in pairs, either D + D - or D 0 anti D 0 , at a center-of-mass energy below the threshold for DD production. The unique kinematics of the production allow us to isolate the charmed meson signal clearly and unambiguously. The data were collected with the MARK III Spectrometer, a large solid angle magnetic detector. Our data sample corresponds to an integrated luminosity of approximately 9.3 inverse picobarns. New results will be presented on the absolute branching ratios of D mesons into hadronic final states, branching ratios for three body decays via pseudoscalar-vector intermediate states, and branching ratios for Cabibbo allowed and Cabibbo suppressed decays. Inclusive and exclusive branching ratios for the semi-leptonic decays of D mesons will be presented, as well as the first measurement of the vector form factor in the decay D 0 → K - e + nu, evidence for interference in D + decays, and new information on the contributions of W exchange diagrams to D 0 decays

A lattice QCD determination of potentials between pairs of static-light mesons

International Nuclear Information System (INIS)

Hetzenegger, Martin

2011-01-01

Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B * , a D or a D * heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z + (4430).

Cosmological evolution in vector-tensor theories of gravity

International Nuclear Information System (INIS)

Beltran Jimenez, Jose; Maroto, Antonio L.

2009-01-01

We present a detailed study of the cosmological evolution in general vector-tensor theories of gravity without potential terms. We consider the evolution of the vector field throughout the expansion history of the Universe and carry out a classification of models according to the behavior of the vector field in each cosmological epoch. We also analyze the case in which the Universe is dominated by the vector field, performing a complete analysis of the system phase map and identifying those attracting solutions which give rise to accelerated expansion. Moreover, we consider the evolution in a universe filled with a pressureless fluid in addition to the vector field and study the existence of attractors in which we can have a transition from matter domination to vector domination with accelerated expansion so that the vector field may play the role of dark energy. We find that the existence of solutions with late-time accelerated expansion is a generic prediction of vector-tensor theories and that such solutions typically lead to the presence of future singularities. Finally, limits from local gravity tests are used to get constraints on the value of the vector field at small (Solar System) scales.

Semileptonic decays of B mesons into excited charm mesons: leading order and 1/mc contributions

International Nuclear Information System (INIS)

Mannel, T.

1994-01-01

We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays of a B meson into excited daughter mesons. For an excited daughter meson with charm, a single form factor is needed at leading order, while five form factors and two dimensionful constants are needed to order 1/m c in the heavy quark expansion. For non-charmed final states, a total of four form factors are needed at leading order. For the process B→D(*)Xlν, four form factors are also needed at leading order. (orig.)

Modified quark-meson coupling model for nuclear matter

International Nuclear Information System (INIS)

Jin, X.; Jennings, B.K.

1996-01-01

The quark-meson coupling model for nuclear matter, which describes nuclear matter as nonoverlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons, is modified by introducing medium modification of the bag constant. We model the density dependence of the bag constant in two different ways: One invokes a direct coupling of the bag constant to the scalar meson field, and the other relates the bag constant to the in-medium nucleon mass. Both models feature a decreasing bag constant with increasing density. We find that when the bag constant is significantly reduced in nuclear medium with respect to its free-space value, large canceling isoscalar Lorentz scalar and vector potentials for the nucleon in nuclear matter emerge naturally. Such potentials are comparable to those suggested by relativistic nuclear phenomenology and finite-density QCD sum rules. This suggests that the reduction of bag constant in nuclear medium may play an important role in low- and medium-energy nuclear physics. copyright 1996 The American Physical Society

Flavor non-universal gauge interactions and anomalies in B-meson decays

Science.gov (United States)

Tang, Yong; Wu, Yue-Liang

2018-02-01

Motivated by flavor non-universality and anomalies in semi-leptonic B-meson decays, we present a general and systematic discussion about how to construct anomaly-free U(1)‧ gauge theories based on an extended standard model with only three right-handed neutrinos. If all standard model fermions are vector-like under this new gauge symmetry, the most general family non-universal charge assignments, (a,b,c) for three-generation quarks and (d,e,f) for leptons, need satisfy just one condition to be anomaly-free, 3(a+b+c) = - (d+e+f). Any assignment can be linear combinations of five independent anomaly-free solutions. We also illustrate how such models can generally lead to flavor-changing interactions and easily resolve the anomalies in B-meson decays. Probes with {{B}}{s} - {{\\bar B}}{s} mixing, decay into τ ±, dilepton and dijet searches at colliders are also discussed. Supported by the Grant-in-Aid for Innovative Areas (16H06490)

ω(→ π+π−π0) meson photoproduction on proton

Indian Academy of Sciences (India)

PRAMANA c Indian Academy of Sciences. Vol. 75, No. 4. — journal of. October 2010 physics pp. 665–674 ω(→ π+π−π0) meson photoproduction on proton ... The vector meson can probe the low-lying nucleonic resonances [7] because it ... reaction amplitudes from the latest measurement of the four-momentum transfer.

A lattice QCD determination of potentials between pairs of static-light mesons

Energy Technology Data Exchange (ETDEWEB)

Hetzenegger, Martin

2011-07-04

Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B{sup *}, a D or a D{sup *} heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z{sup +}(4430).

Measurements of B Meson Decays to omega K* and omega rho

Energy Technology Data Exchange (ETDEWEB)

Aubert, B.

2005-02-14

We describe searches for B meson decays to the charmless vector-vector final states {omega}K* and {omega}{rho} in 89 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation at {radical}s = 10.58 GeV.

Scalar meson field and many-body forces. Chapter 23

International Nuclear Information System (INIS)

Nyman, E.M.

1979-01-01

In applications of field theory to the theory of the nuclear forces, one has frequently assumed that there is a scalar meson. It will then be responsible for most of the medium-range attraction between the nucleons. According to current ideas, however, it is possible to account for the medium-range attraction without an elementary sigma meson. This approach requires a careful treatment of the exchange of interacting pairs of π mesons, such as to include those ππ interactions which are responsible for the formation and decay of the sigma meson. Recently, the scalar field in the nuclear many-body problem has begun to receive more attention. There are two reasons for this change of philosophy. One reason is the discovery of neutron stars. In neutron stars, the nucleon number density can be much higher than in nuclei. One therefore wants to derive the equation of state from a relativistic many-body theory. This forces one to deal explicitly with a set of mesons, such that in the non-relativistic limit one recovers the one-boson-exchange potential. (Auth.)

Measurement of elastic electroproduction of $\\phi$ mesons 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.; 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.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; 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.; Ghazarian, S.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; 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.; 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.; 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.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstrom, M.; 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, 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, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; 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.; 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.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.I.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; 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.; 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.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.

2000-01-01

The elastic electroproduction of phi mesons is studied at HERA with the H1 detector for photon virtualities 1 < Q^2 < 15 GeV^2 and hadronic centre of mass energies 40 < W < 130 GeV. The Q^2 and t dependences of the cross section are extracted (t being the square of the four-momentum transfer to the target proton). When plotted as function of (Q^2 + M_V^2) and scaled by the appropriate SU(5) quark charge factor, the phi meson cross section agrees within errors with the cross sections of the vector mesons V = rho, omega and J/psi. A detailed analysis is performed of the phi meson polarisation state and the ratio of the production cross sections for longitudinally and transversely polarised phi mesons is determined. A small but significant violation of s-channel helicity conservation (SCHC) is observed.

Relativistic meson spectroscopy in momentum space

International Nuclear Information System (INIS)

Hersbach, H.

1994-01-01

In this paper a relativistic constituent-quark model based on the Ruijgrok--de Groot formalism is presented. The quark model is not defined in configuration space, but in momentum space. The complete meson spectrum, with the exception of the self-conjugate light unflavored mesons, is calculated. The potential used consists of a one-gluon exchange (OGE) part and a confining part. For the confining part a relativistic generalization of the linear plus constant potential was used, which is well defined in momentum space without introducing any singularities. For the OGE part several potentials were investigated. Retardations were included at all places. By the use of a fitting procedure involving 52 well-established mesons, but results were obtained for a potential consisting of a purely vector Richardson potential and a purely scalar confining potential. Reasonable results were also obtained for a modified Richardson potential. Most meson masses, with the exception of the π, the K, and the K 0 * , were found to be quite well described by the model

Weak hadronic currents in compensation theory

International Nuclear Information System (INIS)

Pappas, R.C.

1975-01-01

Working within the framework of a compensation theory of strong and weak interactions, it is shown that: (1) an axial vector baryon number current can be included in the weak current algebra if certain restrictions on the K-meson strong couplings are relaxed; (2) the theory does not permit the introduction of strange currents of the chiral form V + A; and (3) the assumption that the superweak currents of the theory cannot contain certain CP conserving terms can be justified on the basis of compensation requirements

Cosmological Solutions of Tensor–Vector Theories of Gravity by ...

Indian Academy of Sciences (India)

We consider tensor–vector theories by varying the space- time–matter coupling ... solutions by considering the character of critical points of the theory and their stability .... light (Magueijo 2003) that has arisen from the possibility of varying fine structure constant. ... Vector-like dark energy displays a series of properties that.

High energy photoproduction of the rho and rho' vector mesons

International Nuclear Information System (INIS)

Bronstein, J.M.

1977-01-01

In an experiment in the broad band photon beam at Fermilab diffractive production of 2π + and 4π +- states from Be, Al, Cu, and Pb targets was observed. The 2π + data are dominated by the rho(770) and the 4π +- is dominated by the rho'(1500). The energy dependence of rho photoproduction from Be was measured, and no evidence was seen for energy variation of the forward cross section in the range 30 to 160 GeV. The forward cross section is consistent with its average value d sigma/dtlt. slash 0 = 3.42 +- 0.28 μb/GeV 2 over the entire range. For the /sub rho'// a mass of 1487 +- 20 MeV and a width of 675 +- 60 MeV are obtained. All quoted errors are statistical. A standard optical model analysis of the A dependence of the rho and rho'/ photoproduction yields the following results. f/sub rho'/ 2 /f/sub rho/ 2 = 3.7 +- 0.7, sigma /sub rho'//sigma /sub rho/ = 1.05 +- 0.18. Results for the photon coupling constants are in good agreement with GVMD and with the e + e - storage ring results. The approximate equality of the rho-nucleon and rho'-nucleon total cross sections is inconsistent with the diagonal version of GVMD and provides strong motivation for including transitions between different vector mesons in GVMD

Local algebras in Euclidean quantum field theory

International Nuclear Information System (INIS)

Guerra, Francesco.

1975-06-01

The general structure of the local observable algebras of Euclidean quantum field theory is described, considering the very simple examples of the free scalar field, the vector meson field, and the electromagnetic field. The role of Markov properties, and the relations between Euclidean theory and Hamiltonian theory in Minkowski space-time are especially emphasized. No conflict appears between covariance (in the Euclidean sense) and locality (in the Markov sense) on one hand and positive definiteness of the metric on the other hand [fr

Meson thermalization by baryon injection in D4/D6 model

Science.gov (United States)

Rezaei, Z.

2016-12-01

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-Nc QCD is considered as a theory governing this quark-gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

Stealth configurations in vector-tensor theories of gravity

Science.gov (United States)

Chagoya, Javier; Tasinato, Gianmassimo

2018-01-01

Studying the physics of compact objects in modified theories of gravity is important for understanding how future observations can test alternatives to General Relativity. We consider a subset of vector-tensor Galileon theories of gravity characterized by new symmetries, which can prevent the propagation of the vector longitudinal polarization, even in absence of Abelian gauge invariance. We investigate new spherically symmetric and slowly rotating solutions for these systems, including an arbitrary matter Lagrangian. We show that, under certain conditions, there always exist stealth configurations whose geometry coincides with solutions of Einstein gravity coupled with the additional matter. Such solutions have a non-trivial profile for the vector field, characterized by independent integration constants, which extends to asymptotic infinity. We interpret our findings in terms of the symmetries and features of the original vector-tensor action, and on the number of degrees of freedom that it propagates. These results are important to eventually describe gravitationally bound configurations in modified theories of gravity, such as black holes and neutron stars, including realistic matter fields forming or surrounding the object.

Black holes in vector-tensor theories and their thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Fan, Zhong-Ying [Guangzhou University, Center for Astrophysics, School of Physics and Electronic Engineering, Guangzhou (China)

2018-01-15

In this paper, we study Einstein gravity either minimally or non-minimally coupled to a vector field which breaks the gauge symmetry explicitly in general dimensions. We first consider a minimal theory which is simply the Einstein-Proca theory extended with a quartic self-interaction term for the vector field. We obtain its general static maximally symmetric black hole solution and study the thermodynamics using Wald formalism. The aspects of the solution are much like a Reissner-Nordstroem black hole in spite of that a global charge cannot be defined for the vector. For non-minimal theories, we obtain a lot of exact black hole solutions, depending on the parameters of the theories. In particular, many of the solutions are general static and have maximal symmetry. However, there are some subtleties and ambiguities in the derivation of the first laws because the existence of an algebraic degree of freedom of the vector in general invalids the Wald entropy formula. The thermodynamics of these solutions deserves further studies. (orig.)

Meson thermalization by baryon injection in D4/D6 model

Energy Technology Data Exchange (ETDEWEB)

Rezaei, Z., E-mail: z.rezaei@aut.ac.ir [Department of Physics, Tafresh University, Tafresh 39518 79611 (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2016-12-15

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-N{sub c} QCD is considered as a theory governing this quark–gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

Meson thermalization by baryon injection in D4/D6 model

International Nuclear Information System (INIS)

Rezaei, Z.

2016-01-01

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-N_c QCD is considered as a theory governing this quark–gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

On meson resonances and chiral symmetry

International Nuclear Information System (INIS)

Lutz, M.F.M.

2003-07-01

We study meson resonances with quantum numbers J P = 1 + in terms of the chiral SU(3) Lagrangian. At leading order a parameter-free prediction is obtained for the scattering of Goldstone bosons off vector mesons with J P = 1 - once we insist on approximate crossing symmetry of the unitarized scattering amplitude. A resonance spectrum arises that is remarkably close to the empirical pattern. In particular, we find that the strangeness-zero resonances h 1 (1380), f 1 (1285) and b 1 (1235) are formed due to strong K anti K μ and K K μ channels. This leads to large coupling constants of those resonances to the latter states. (orig.)

Annihilation diagrams in two-body nonleptonic decays of charmed mesons

International Nuclear Information System (INIS)

Bedaque, P.; Das, A.; Mathur, V.S.

1994-06-01

In the pole-dominance model for the two-body nonleptonic decays of charmed mesons D → PV and D → VV, it is shown that the contributions of the intermediate pseudoscalar and the axial-vector meson poles cancel each other in the annihilation diagrams in the chiral limit. In the same limit, the annihilation diagrams for the D → PP decays vanish independently. (author). 6 refs, 3 figs

First measurement of coherent $\\phi$-meson photoproduction on deuteron at low energies

Energy Technology Data Exchange (ETDEWEB)

Tsutomu Mibe; Haiyan Gao; Kenneth Hicks; Kevin Kramer; Stepan Stepanyan; David Tedeschi; Moscov Amaryan; Pawel Ambrozewicz; Marco Anghinolfi; G. Asryan; Gerard Audit; Harutyun Avakian; Hovhannes Baghdasaryan; Nathan Baillie; Jacques Ball; Nathan Baltzell; Marco Battaglieri; Ivan Bedlinski; Ivan Bedlinskiy; Matthew Bellis; Nawal Benmouna; Barry Berman; Angela Biselli; Lukasz Blaszczyk; Sylvain Bouchigny; Sergey Boyarinov; Robert Bradford; Derek Branford; William Briscoe; William Brooks; Stephen Bueltmann; Volker Burkert; Cornel Butuceanu; John Calarco; Sharon Careccia; Daniel Carman; Shifeng Chen; Philip Cole; Patrick Collins; Philip Coltharp; Donald Crabb; Hall Crannell; Volker Crede; John Cummings; Natalya Dashyan; Rita De Masi; Raffaella De Vita; Enzo De Sanctis; Pavel Degtiarenko; Alexandre Deur; Kahanawita Dharmawardane; Richard Dickson; Chaden Djalali; Gail Dodge; Joseph Donnelly; David Doughty; Michael Dugger; Oleksandr Dzyubak; Hovanes Egiyan; Kim Egiyan; Lamiaa Elfassi; Latifa Elouadrhiri; Paul Eugenio; Gleb Fedotov; Gerald Feldman; Herbert Funsten; Michel Garcon; Gagik Gavalian; Gerard Gilfoyle; Kevin Giovanetti; Francois-Xavier Girod; John Goetz; Atilla Gonenc; Christopher Gordon; Ralf Gothe; Keith Griffioen; Michel Guidal; Nevzat Guler; Lei Guo; Vardan Gyurjyan; Cynthia Hadjidakis; Kawtar Hafidi; Hayk Hakobyan; Rafael Hakobyan; Charles Hanretty; John Hardie; F. Hersman; Ishaq Hleiqawi; Maurik Holtrop; Charles Hyde; Charles Hyde-Wright; Yordanka Ilieva; David Ireland; Boris Ishkhanov; Eugeny Isupov; Mark Ito; David Jenkins; Hyon-Suk Jo; John Johnstone; Kyungseon Joo; Henry Juengst; Narbe Kalantarians; James Kellie; Mahbubul Khandaker; Wooyoung Kim; Andreas Klein; Franz Klein; Alexei Klimenko; Mikhail Kossov; Zebulun Krahn; Laird Kramer; V. Kubarovsky; Joachim Kuhn; Sebastian Kuhn; Sergey Kuleshov; Viacheslav Kuznetsov; Jeff Lachniet; Jean Laget; Jorn Langheinrich; David Lawrence; Tsung-shung Lee; Ji Li; Kenneth Livingston; Haiyun Lu; Marion MacCormick; Claude Marchand; Nikolai Markov; Paul Mattione; Bryan McKinnon; Bernhard Mecking; Joseph Melone; Mac Mestayer; Curtis Meyer; Konstantin Mikhaylov; Ralph Minehart; Marco Mirazita; Rory Miskimen; Viktor Mokeev; Kei Moriya; Steven Morrow; M. Moteabbed; E. Munevar; Gordon Mutchler; P. Nadel-Turonski; Rakhsha Nasseripour; Silvia Niccolai; Gabriel Niculescu; Maria-Ioana Niculescu; Bogdan Niczyporuk; Megh Niroula; Rustam Niyazov; Mina Nozar; Mikhail Osipenko; Alexander Ostrovidov; K. Park; Evgueni Pasyuk; Craig Paterson; S. Anefalos Pereira; Joshua Pierce; Nikolay Pivnyuk; Dinko Pocanic; Oleg Pogorelko; S. Pozdniakov; John Price; Yelena Prok; Dan Protopopescu; Brian Raue; Gregory Riccardi; Giovanni Ricco; Marco Ripani; Barry Ritchie; Federico Ronchetti; Guenther Rosner; Patrizia Rossi; Franck Sabatie; Julian Salamanca; Carlos Salgado; Joseph Santoro; Vladimir Sapunenko; Reinhard Schumacher; Vladimir Serov; Youri Sharabian; Dmitri Sharov; Nikolay Shvedunov; Elton Smith; Lee Smith; Daniel Sober; Daria Sokhan; A. Stavinsky; Samuel Stepanyan; B.E. Stokes; Paul Stoler; I.I. Strakovsky; Steffen Strauch; Mauro Taiuti; Ulrike Thoma; Avtandil Tkabladze; Svyatoslav Tkachenko; Luminita Todor; Clarisse Tur; Maurizio Ungaro; Michael Vineyard; Alexander Vlassov; Daniel Watts; Lawrence Weinstein; Dennis Weygand; M. Williams; Elliott Wolin; Michael Wood; Amrit Yegneswaran; Lorenzo Zana; Jixie Zhang; Bo Zhao; Zhiwen Zhao

2007-11-01

The cross section and decay angular distributions for the coherent \\phi meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t =(p_{\\gamma}-p_{\\phi})^2 =-2 GeV^2/c^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a re-scattering model. In a framework of vector meson dominance, the data are consistent with the total \\phi-N cross section \\sigma_{\\phi N} at about 10 mb. If vector meson dominance is violated, a larger \\sigma_{\\phi N} is possible by introducing larger t-slope for the \\phi N \\to \\phi N process than that for the \\gamma N \\to \\phi N process. The decay angular distributions of the \\phi are consistent with helicity conservation.

Non-leptonic heavy meson decays - Theory Status

International Nuclear Information System (INIS)

Feldmann, T.

2014-08-01

The author briefly reviews the status and recent progress in the theoretical understanding of non-leptonic decays of beauty and charm hadrons. Focusing on a personal selection of topics, this covers perturbative calculations in quantum chromodynamics, analyses using flavour symmetries of strong interactions, and the modelling of the relevant hadronic input functions. The dynamics of strong interactions in non-leptonic decays of heavy mesons is extremely complex. While one has to admit that on the theory side a conceptual breakthrough for the systematic calculation of non-factorizable hadronic effect is still lacking, the combination of several theoretical methods in many cases still gives a satisfactory phenomenological picture. We have to note that: -) short-distance kernels in the QCD factorization approach are now being calculated at NNLO for a variety of decays; -) systematic studies of SU(3) F flavour-symmetry breaking effects on the basis of phenomenological data are available; and -) the ongoing improvement of the experimental situation leads to better knowledge on hadronic input parameters and more reliable estimates of systematic theoretical uncertainties

Low-energy photoproduction of omega-mesons

CERN Document Server

Barth, J; Glander, K H; Hannappel, J; Jöpen, N; Klein, F; Lawall, R; Menze, D; Neuerburg, W; Ostrick, M; Paul, E; Schulday, I; Schwille, W J; Wiegers, B; Ernst, J; Kalinowsky, H; Klempt, E; Link, J; Pee, H V; Klein, F J; Wieland, F W; Wisskirchen, J; Wu, C

2003-01-01

The photoproduction of the vector meson omega has been studied between threshold and W=2.4 GeV with the SAPHIR detector at the Bonn electron stretcher ring ELSA. Besides, the total cross-sections angular distributions in the CMS and decay angular distributions in the helicity and Gottfried-Jackson systems have been measured.

Low-energy photoproduction of PHI-mesons

CERN Document Server

Barth, J; Glander, K H; Hannappel, J; Jöpen, N; Klein, F J; Klein, F; Lawall, R; Menze, D; Neuerburg, W; Ostrick, M; Paul, E; Schulday, I; Schwille, W J; Wiegers, B; Ernst, J; Kalinowsky, H; Klempt, E; Link, J; Pee, H V; Wieland, F W; Wisskirchen, J; Wu, C

2003-01-01

Photoproduction of PHI-vector-mesons has been studied from reaction threshold up to W=2.4 GeV with the SAPHIR spectrometer at the Bonn electron stretcher ring ELSA. Total cross-sections, differential cross-sections and decay angular distributions were measured. We find evidence for strong non-diffractive contributions to PHI photoproduction. (orig.)

MEASUREMENT OF POLARIZATION OBSERVABLES IN VECTOR MESON PHOTOPRODUCTION USING A TRANSVERSELY-POLARIZED FROZEN-SPIN TARGET AND POLARIZED PHOTONS AT CLAS, JEFFERSON LAB

Energy Technology Data Exchange (ETDEWEB)

Roy, Priyashree [Florida State Univ., Tallahassee, FL (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-11-30

The study of baryon resonances provides a deeper understanding of the strong interaction because the dynamics and relevant degrees of freedom hidden within them are re ected by the properties of the excited states of baryons. Higher-lying excited states at and above 1.7 GeV/c2 are generally predicted to have strong couplings to final states involving a heavier meson, e. g. one of the vector mesons, ρ, ω φ, as compared to a lighter pseudoscalar meson, e. g. π and η. Decays to the ππΝ final states via πΔ also become more important through the population of intermediate resonances. We observe that nature invests in mass rather than momentum. The excited states of the nucleon are usually found as broadly overlapping resonances which may decay into a multitude of final states involving mesons and baryons. Polarization observables make it possible to isolate single resonance contributions from other interference terms. The CLAS g9 (FROST) experiment, as part of the N* spectroscopy program at Je?erson Laboratory, accumulated photoproduction data using circularly- & linearly-polarized photons incident on a transversely-polarized butanol target (g9b experiment) in the photon energy range 0:3-2:4 GeV & 0:7-2:1 GeV, respectively. In this work, the analysis of reactions and polarization observables which involve two charged pions, either in the fully exclusive reaction γρ -> ρπ+π- or in the semi-exclusive reaction with a missing neutral pion, γρ -> ρπ+π-(π0) will be presented. For the reaction ρπ+π-, eight polarization observables (Is, Ic, Px, Py, Psx; y, Pcx; y) have been extracted. The high statistics data rendered it possible to extract these observables in three dimensions. All of them are first-time measurements. The fairly good agreement of Is, Ic obtained from this analysis with the experimental results from a previous CLAS experiment provides support for the first-time measurements. For the reaction γρ -> ρω -> ρπ+π(π0, five polarization

Symmetry breaking due to quantum fluctuations in massless field theories

International Nuclear Information System (INIS)

Ghose, P.; Datta, A.

1977-10-01

It is shown that quantum fluctuations can act as the driving mechanism for the spontaneous breakdown of both scale and the discrete phi→-phi symmetries in a lamdaphi 4 theory which is massless and scale invariant in the tree approximation. Consequently dimensional transformation occurs and the dimensionless and only parameter lambda in the theory is fixed and replaced by the vacuum expectation value of the field. These results are shown to be consistent with the appropriate renormalization group equation for the theory. A scalar electrodynamics which is massless and scale invariant in the tree approximation is also considered, and it is shown that the Higgs meson in such a theory is much heavier than the vector meson for small values of the gauge coupling constant e. Another interesting consequence of such a theory is that it possesses vortex-line solutions only when quantum fluctuations are taken into account

Meson-baryon coupling constants from a chiral-invariant SU(3) Lagrangian and application to NN scattering

International Nuclear Information System (INIS)

Stoks, V.G.J.

1997-01-01

We present a chiral-invariant meson-baryon Lagrangian which describes the interactions of the baryon octet with the lowest-mass meson nonets. The nonlinear realization of the chiral symmetry generates pair-meson interaction vertices. The corresponding pair-meson coupling constants can all be expressed in terms of the meson-nucleon-nucleon pseudovector, scalar, and vector coupling constants, and their corresponding F/(F+D) ratios, and for which empirical estimates are given. We show that it is possible to construct an NN potential of reasonable quality satisfying these theoretical and empirical constraints. (orig.)

Meson masses in electromagnetic fields with Wilson fermions

Science.gov (United States)

Bali, G. S.; Brandt, B. B.; Endrődi, G.; Gläßle, B.

2018-02-01

We determine the light meson spectrum in QCD in the presence of background magnetic fields using quenched Wilson fermions. Our continuum extrapolated results indicate a monotonous reduction of the connected neutral pion mass as the magnetic field grows. The vector meson mass is found to remain nonzero, a finding relevant for the conjectured ρ -meson condensation at strong magnetic fields. The continuum extrapolation was facilitated by adding a novel magnetic field-dependent improvement term to the additive quark mass renormalization. Without this term, sizable lattice artifacts that would deceptively indicate an unphysical rise of the connected neutral pion mass for strong magnetic fields are present. We also investigate the impact of these lattice artifacts on further observables like magnetic polarizabilities and discuss the magnetic field-induced mixing between ρ -mesons and pions. We also derive Ward-Takashi identities for QCD +QED both in the continuum formulation and for (order a -improved) Wilson fermions.

Pion-pion and pion-kaon interaction in the meson exchange picture

International Nuclear Information System (INIS)

Lohse, D.

1989-10-01

Following the general line of the Bonn NN-interaction, a model for pseudoscalar-pseudoscalar meson interaction has been constructed and applied consistently to ππ and Kπ scattering. The phases can be reproduced with vector meson t- and s-channel exchange up to 1 GeV. The bare masses of the vector mesons turn out to be in the range of 1.1 GeV, depending on the form factor. We use a coupled channel formalism, which is crucial to explain the S * (975) resonance as a bound anti KK state. Beyond 1 GeV the data require a pseudoscalar-pseudoscalar coupling to a scalar octet (J P =0 + ) to fit the s-wave phases in the isospin-0 π and isospin-1/2 Kπ channels. We apply both scalar coupling and derivative coupling. The latter avoids introducing additional degrees of freedom and produces an acceptable fit to the J=0 phase shift data. (orig.) [de

Evolution equation for the B-meson distribution amplitude in the heavy-quark effective theory in coordinate space

International Nuclear Information System (INIS)

Kawamura, Hiroyuki; Tanaka, Kazuhiro

2010-01-01

The B-meson distribution amplitude (DA) is defined as the matrix element of a quark-antiquark bilocal light-cone operator in the heavy-quark effective theory, corresponding to a long-distance component in the factorization formula for exclusive B-meson decays. The evolution equation for the B-meson DA is governed by the cusp anomalous dimension as well as the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-type anomalous dimension, and these anomalous dimensions give the ''quasilocal'' kernel in the coordinate-space representation. We show that this evolution equation can be solved analytically in the coordinate space, accomplishing the relevant Sudakov resummation at the next-to-leading logarithmic accuracy. The quasilocal nature leads to a quite simple form of our solution which determines the B-meson DA with a quark-antiquark light-cone separation t in terms of the DA at a lower renormalization scale μ with smaller interquark separations zt (z≤1). This formula allows us to present rigorous calculation of the B-meson DA at the factorization scale ∼√(m b Λ QCD ) for t less than ∼1 GeV -1 , using the recently obtained operator product expansion of the DA as the input at μ∼1 GeV. We also derive the master formula, which reexpresses the integrals of the DA at μ∼√(m b Λ QCD ) for the factorization formula by the compact integrals of the DA at μ∼1 GeV.

Meson and baryon correlation studies using the PEP-TPC/2γ Facility

International Nuclear Information System (INIS)

Ronan, M.T.

1991-03-01

Results on vector meson, and strange and charmed-baryon production are presented for data taken during the period 1982--1986 using the TPC/2γ detector at PEP. Vector mesons (ρ 0 , K * and φ) with 0, 1 and 2 strange quarks are used to obtain redundant measures of strange-quark suppression and of the vector to pseudoscalar ratio in hadronization. Measurements of the production rates of Λ, Ξ - , Ω and Ξ *0 hyperons and for the Λ c and of rapidity correlations between Λ bar Λ pairs provide sensitive tests of baryon production in fragmentation models. In addition, two- and three-particle correlations between like sign pions provide further evidence for the Bose-Einstein effect in e + e - interactions including the relativistic motion of particle sources. 9 refs., 7 figs

A model of mesons based on χSB in the light-front frame

International Nuclear Information System (INIS)

Susskind, L.; Burkardt, M.

1994-01-01

Spontaneous breaking of chiral symmetry is discussed in the light-cone framework. The essential ingredient is an infinite number of constituents near zero light-cone momentum. These high (light-cone) energy degrees of freedom freeze out and leave behind some explicit symmetry breaking in the low (light-cone) energy effective Hamiltonian. Connections with Regge theory and soft pion theorems are discussed. Taking the order parameter to be the 4-th component of a chiral 4-vector, the effect of the spontaneous symmetry breaking on meson masses and decay width is calculated and compared with experimental data

Two-body spectra of pseudoscalar mesons with an O(a2)-improved lattice action using Wilson fermions

International Nuclear Information System (INIS)

Fiebig, H.R.; Mihaly, A.; Woloshyn, R.M.

1998-01-01

We extend our calculations with the second-order tree-level and tadpole improved next-nearest-neighbor action to meson-meson systems. Correlation matrices built from interpolating fields representing two pseudoscalar mesons (π-π) with relative momenta vector-p are diagonalized, and the mass spectrum is extracted. Link variable fuzzing and operator smearing at both sinks and sources is employed. Calculations are presented for two values of the hopping parameter. The spectrum is used to discuss the residual interaction in the meson-meson system. (orig.)

Exclusive vector meson production with leading neutrons in a saturation model for the dipole amplitude in mixed space

Science.gov (United States)

Amaral, J. T.; Becker, V. M.

2018-05-01

We investigate ρ vector meson production in e p collisions at HERA with leading neutrons in the dipole formalism. The interaction of the dipole and the pion is described in a mixed-space approach, in which the dipole-pion scattering amplitude is given by the Marquet-Peschanski-Soyez saturation model, which is based on the traveling wave solutions of the nonlinear Balitsky-Kovchegov equation. We estimate the magnitude of the absorption effects and compare our results with a previous analysis of the same process in full coordinate space. In contrast with this approach, the present study leads to absorption K factors in the range of those predicted by previous theoretical studies on semi-inclusive processes.

Statistical Theory of the Vector Random Decrement Technique

DEFF Research Database (Denmark)

Asmussen, J. C.; Brincker, Rune; Ibrahim, S. R.

1999-01-01

decays. Due to the speed and/or accuracy of the Vector Random Decrement technique, it was introduced as an attractive alternative to the Random Decrement technique. In this paper, the theory of the Vector Random Decrement technique is extended by applying a statistical description of the stochastic...

Recent results of hadronic decays of J/psi into vector-tensor from MARK III

International Nuclear Information System (INIS)

Becker, J.J.; Blaylock, G.T.; Bolton, T.; Brown, J.S.

1987-02-01

From a data sample of 5.8 x 10 6 J/psi's collected by the MARK III detector at the storage ring SPEAR at SLAC, two-body decay modes of the J/psi into a vector and a tensor meson have been measured. From the studies of the tensor meson, recoiling against the ideally mixed and well understood vector mesons, quark correlations are established and compared with the theoretical expectations of the J/psi decays and the SU(3) predictions. The beginnings of a similar systematic study of the two-body vector scalar decays are also presented

Effects of an electromagnetic quark form factor on meson properties

International Nuclear Information System (INIS)

Silvestre-Brac, B.

2002-01-01

A form factor is introduced in the quark electromagnetic current. Its effect is analyzed on charge mean square radii and form factors in the mesonic sector. The decay of a vector meson into lepton-antilepton pair is also affected. Two different expressions for the form factors, and two different types of quark potential are tested and some relativistic kinematical corrections are proposed. In any case the introduction of a quark form factor greatly improves the agreement with experimental data

Vector and tensor meson production in quasi-two-body final states using the dual fermion model

International Nuclear Information System (INIS)

Becker, L.; Matthaeus, E.; Weigt, G.

1976-01-01

Phenomenological dual fermion amplitudes are obtained by using Neveu-Schwarz-Ramond model as a guide to incorporate half-integer spin. The model relates the production mechanism of different resonances lying on the same degenerate Regge trajectory, thus allowing a simultaneous description of vector and tensor meson production. A characteristic feature of the amplitudes is their non-evasive coupling structure. Predictions of the model for rho 0 -f-g 0 , ω-A 2 - and anti K*(890)-anti K*(1420) production in quasi-two-body reactions are compared with experimental data. The differential cross sections for natural and unnatural spin-parity t-channel exchanges as well as their contributions to different helicities of the produced resonances are given. In particular, new properties arise from the non-evasive pion exchange. Reasonable agreement with the data is found. (Auth.)

Vector and tensor meson production in quasi-two-body final states using the dual fermion model

International Nuclear Information System (INIS)

Becker, L.; Matthaeus, E.; Weigt, G.

1975-01-01

Phenomenological dual fermion amplitudes are obtained by using the Neveu-Schwarz-Ramond model as a guide to incorporate half-integer spin. The model relates the production mechanism of different resonances lying on the same degenerated Regge trajectory, thus allowing a simultaneous description of vector and tensor meson production. A characteristic feature of the amplitudes is their non-evasive coupling structure. Predictions of the model for rho 0 - f - g 0 , ω - A 2 - and anti K-890 and anti K-1420 resonances production in quasi-two-body reactions are compared with experimental data. The differential cross sections for natural and unnatural spin-parity t-channel exchanges as well as their contributions to different helicities of the produced resonances are given. In particular, new properties arise from the non-evasive pion exchange. Reasonable agreement with the data is found. (author)

The nucleon-nucleon interaction from a realistic pseudoscalar-vector chiral lagrangian

International Nuclear Information System (INIS)

Kaiser, N.; Meissner, U.G.; Massachusetts Inst. of Tech., Cambridge

1990-01-01

We investigate the static nucleon-nucleon potential in the framework of a non-linear chiral meson theory. The model includes pions as well as the vector mesons ρ and ω. All parameters are fixed in the meson sector and predictions about the nucleon-nucleon interaction follow without adjusting any parameters. We use an S-matrix approach to calculate correlated two-pion exchange between two solitons. The most prominent feature of this two-pion exchange is that it leads very natural to attraction in the scalar-isoscalar channel. We also discuss the effect of πp correlations on the central potential, and present the spectral function related to the correlated two-pion exchange. Furthermore, we study the form factors of the nucleon sources related to the two-pion exchange and find that they are of dipole type with typical cutoff scales Λ D ≅ 700 MeV. We also discuss the destructive interference of π- and ρ-exchange in the isovector tensor potential. Altogether, we present a unified treatment of meson exchange phenomenology based on a serious model of the nucleon. Finally, we point out the limitations of the model and discuss some further applications. (orig.)

Importance of Nonperturbative QCD Parameters for Bottom Mesons

Directory of Open Access Journals (Sweden)

A. Upadhyay

2014-01-01

Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.

Mesons versus quasi-normal modes: undercooling and overheating

NARCIS (Netherlands)

Paredes Galan, A.; Peeters, K.; Zamaklar, m.

2008-01-01

In holographic models of gauge theories with matter, there generically exists a first order phase transition in which mesons dissociate. We perform a careful analysis of the meson and quasi-particle spectra in the overheated resp. undercooled regimes close to the junction of the two phases. We show

Vector optimization theory, applications, and extensions

CERN Document Server

Jahn, Johannes

2011-01-01

This new edition of a key monograph has fresh sections on the work of Edgeworth and Pareto in its presentation in a general setting of the fundamentals and important results of vector optimization. It examines background material, applications and theories.

The renormalization group in effective chiral theories

International Nuclear Information System (INIS)

Varin, T.

2007-09-01

The dilepton production within the heavy ions collisions (CERN/SPS, SIS/HADES, RHIC) and the behaviour of vector mesons (in particular the rho meson) are among the main topics of quantum chromodynamics (QCD) in hadronic matter. One of the main goals is the study of partial or total restoration of chiral symmetry SU(2) x SU(2), for which effective theories need to be used. One of the important difficulties is to build a theory which allows to obtain predictions when approaching the phase transition by taking into account the phenomenological constraints at low temperature and/or density. The model used here (developed by M. Urban) is based on the gauged (rho and al mesons) linear sigma model adjusted (in practice the local symmetry is only approximate) to reproduce the phenomenology very well. The first part of this thesis consists in presenting a new cut-off based regularization scheme preserving symmetry requirements. The motivation of such a method is a correct accounting of quadratic and logarithmic divergences in view of their intensive use for the renormalisation group equations. For illustrative purposes we have applied it to QED in 4 and 5 dimensions. The second part of this work is devoted to the derivation of the RGE and their resolution. In particular, we show that both restorations (traditional and vector manifestation) can be obtained from our equations, but the most likely remains the 'traditional' Ginzburg-Landau scenario. (author)

Two-body spectra of pseudoscalar mesons with an O(a{sup 2})-improved lattice action using Wilson fermions

Energy Technology Data Exchange (ETDEWEB)

Fiebig, H.R. [FIU-University Park, Miami, FL (United States). Phys. Dept.; Markum, H.; Rabitsch, K. [Institut fuer Kernphysik, Technische Universitaet Wien, 1040 Vienna (Austria); Mihaly, A. [Department of Theoretical Physics, Lajos Kossuth University, 4010 Debrecen (Hungary); Woloshyn, R.M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada)

1998-04-01

We extend our calculations with the second-order tree-level and tadpole improved next-nearest-neighbor action to meson-meson systems. Correlation matrices built from interpolating fields representing two pseudoscalar mesons ({pi}-{pi}) with relative momenta vector-p are diagonalized, and the mass spectrum is extracted. Link variable fuzzing and operator smearing at both sinks and sources is employed. Calculations are presented for two values of the hopping parameter. The spectrum is used to discuss the residual interaction in the meson-meson system. (orig.). 6 refs.

Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

International Nuclear Information System (INIS)

Bijnens, Johan; Rössler, Thomas

2015-01-01

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique. Partial analytical results can be found in the appendices. Some examples of cases relevant to lattice QCD are studied numerically. Numerical programs for all results are available as part of the CHIRON package.

Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

Energy Technology Data Exchange (ETDEWEB)

Bijnens, Johan; Rössler, Thomas [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14A, SE 223-62 Lund (Sweden)

2015-11-16

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique. Partial analytical results can be found in the appendices. Some examples of cases relevant to lattice QCD are studied numerically. Numerical programs for all results are available as part of the CHIRON package.

Meson degrees of freedom in nuclei

International Nuclear Information System (INIS)

Delorme, J.

1982-01-01

A review is presented of the successes and shortcomings of the theory of meson degrees of freedom in nuclei with special emphasis on recent progress and on the necessity to bridge the gap with the degrees of freedom of QCD theory. (orig.)

Black holes in vector-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Heisenberg, Lavinia [Institute for Theoretical Studies, ETH Zurich, Clausiusstrasse 47, 8092 Zurich (Switzerland); Kase, Ryotaro; Tsujikawa, Shinji [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Minamitsuji, Masato, E-mail: lavinia.heisenberg@eth-its.ethz.ch, E-mail: r.kase@rs.tus.ac.jp, E-mail: masato.minamitsuji@tecnico.ulisboa.pt, E-mail: shinji@rs.kagu.tus.ac.jp [Centro Multidisciplinar de Astrofisica—CENTRA, Departamento de Fisica, Instituto Superior Tecnico—IST, Universidade de Lisboa—UL, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2017-08-01

We study static and spherically symmetric black hole (BH) solutions in second-order generalized Proca theories with nonminimal vector field derivative couplings to the Ricci scalar, the Einstein tensor, and the double dual Riemann tensor. We find concrete Lagrangians which give rise to exact BH solutions by imposing two conditions of the two identical metric components and the constant norm of the vector field. These exact solutions are described by either Reissner-Nordström (RN), stealth Schwarzschild, or extremal RN solutions with a non-trivial longitudinal mode of the vector field. We then numerically construct BH solutions without imposing these conditions. For cubic and quartic Lagrangians with power-law couplings which encompass vector Galileons as the specific cases, we show the existence of BH solutions with the difference between two non-trivial metric components. The quintic-order power-law couplings do not give rise to non-trivial BH solutions regular throughout the horizon exterior. The sixth-order and intrinsic vector-mode couplings can lead to BH solutions with a secondary hair. For all the solutions, the vector field is regular at least at the future or past horizon. The deviation from General Relativity induced by the Proca hair can be potentially tested by future measurements of gravitational waves in the nonlinear regime of gravity.

Even- and Odd-Parity Charmed Meson Masses in Heavy Hadron Chiral Perturbation Theory

Energy Technology Data Exchange (ETDEWEB)

Thomas Mehen; Roxanne Springer

2005-03-01

We derive mass formulae for the ground state, J{sup P} = 0{sup -} and 1{sup -}, and first excited even-parity, J{sup P} = 0{sup +} and 1{sup +}, charmed mesons including one loop chiral corrections and {Omicron}(1/m{sub c}) counterterms in heavy hadron chiral perturbation theory. We show a variety of fits to the current data. We find that certain parameter relations in the parity doubling model are not renormalized at one loop, providing a natural explanation for the equality of the hyperfine splittings of ground state and excited doublets.

Strange mesonic transition form factor in the chiral constituent quark model

International Nuclear Information System (INIS)

Ito, H.; Ramsey-Musolf, M.J.

1998-01-01

The form factor g ρπ (S) (Q 2 ) of the strange vector current transition matrix element left-angle ρ|bar sγ μ s|π right-angle is calculated within the chiral quark model. A strange vector current of the constituent U and D quarks is induced by kaon radiative corrections and this mechanism yields the nonvanishing values of g ρπ (S) (0). The numerical result at the photon point is consistent with the one given by the φ-meson dominance model, but the falloff in the Q 2 dependence is faster than the monopole form factor. Mesonic radiative corrections are also examined for the electromagnetic ρ-to-π and K * -to-K transition amplitudes. copyright 1998 The American Physical Society

Summary of Meson'98 Workshop

International Nuclear Information System (INIS)

Henley, E.M.

1998-01-01

One never quite knows what to say in a summary. If you were at the sessions, you heard the same talks I did. Perhaps the purpose is to summarize the parallel sessions, but like you, I can only attend one of these sessions. In addition, the time is short, so that this cannot be a real summary. What I will present are impressions of the past two days, and these will certainly be colored by my own views. Thus at the outset, let me apologize for any and all omissions and distortions. I will cover primarily the plenary session talks, but will organize this summary along the following lines: 1. vector (V) mesons; 2. pseudoscalar mesons, and 3. other subjects, notably with electrons. This afternoon's talks are so close in time to this summary that I shall omit them. (author)

Anisotropic cosmological solutions in massive vector theories

Energy Technology Data Exchange (ETDEWEB)

Heisenberg, Lavinia [Institute for Theoretical Studies, ETH Zurich, Clausiusstrasse 47, 8092 Zurich (Switzerland); Kase, Ryotaro; Tsujikawa, Shinji, E-mail: Lavinia.heisenberg@googlemail.com, E-mail: r.kase@rs.tus.ac.jp, E-mail: shinji@rs.kagu.tus.ac.jp [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

2016-11-01

In beyond-generalized Proca theories including the extension to theories higher than second order, we study the role of a spatial component v of a massive vector field on the anisotropic cosmological background. We show that, as in the case of the isotropic cosmological background, there is no additional ghostly degrees of freedom associated with the Ostrogradski instability. In second-order generalized Proca theories we find the existence of anisotropic solutions on which the ratio between the anisotropic expansion rate Σ and the isotropic expansion rate H remains nearly constant in the radiation-dominated epoch. In the regime where Σ/ H is constant, the spatial vector component v works as a dark radiation with the equation of state close to 1/3. During the matter era, the ratio Σ/ H decreases with the decrease of v . As long as the conditions |Σ| || H and v {sup 2} || φ{sup 2} are satisfied around the onset of late-time cosmic acceleration, where φ is the temporal vector component, we find that the solutions approach the isotropic de Sitter fixed point (Σ = 0 = v ) in accordance with the cosmic no-hair conjecture. In the presence of v and Σ the early evolution of the dark energy equation of state w {sub DE} in the radiation era is different from that in the isotropic case, but the approach to the isotropic value w {sub DE}{sup (iso)} typically occurs at redshifts z much larger than 1. Thus, apart from the existence of dark radiation, the anisotropic cosmological dynamics at low redshifts is similar to that in isotropic generalized Proca theories. In beyond-generalized Proca theories the only consistent solution to avoid the divergence of a determinant of the dynamical system corresponds to v = 0, so Σ always decreases in time.

Anisotropic cosmological solutions in massive vector theories

International Nuclear Information System (INIS)

Heisenberg, Lavinia; Kase, Ryotaro; Tsujikawa, Shinji

2016-01-01

In beyond-generalized Proca theories including the extension to theories higher than second order, we study the role of a spatial component v of a massive vector field on the anisotropic cosmological background. We show that, as in the case of the isotropic cosmological background, there is no additional ghostly degrees of freedom associated with the Ostrogradski instability. In second-order generalized Proca theories we find the existence of anisotropic solutions on which the ratio between the anisotropic expansion rate Σ and the isotropic expansion rate H remains nearly constant in the radiation-dominated epoch. In the regime where Σ/ H is constant, the spatial vector component v works as a dark radiation with the equation of state close to 1/3. During the matter era, the ratio Σ/ H decreases with the decrease of v . As long as the conditions |Σ| || H and v 2 || φ 2 are satisfied around the onset of late-time cosmic acceleration, where φ is the temporal vector component, we find that the solutions approach the isotropic de Sitter fixed point (Σ = 0 = v ) in accordance with the cosmic no-hair conjecture. In the presence of v and Σ the early evolution of the dark energy equation of state w DE in the radiation era is different from that in the isotropic case, but the approach to the isotropic value w DE (iso) typically occurs at redshifts z much larger than 1. Thus, apart from the existence of dark radiation, the anisotropic cosmological dynamics at low redshifts is similar to that in isotropic generalized Proca theories. In beyond-generalized Proca theories the only consistent solution to avoid the divergence of a determinant of the dynamical system corresponds to v = 0, so Σ always decreases in time.

Charmed meson production by e+e- annihilation

International Nuclear Information System (INIS)

Wiss, J.E.

1977-08-01

Compelling evidence is presented for the production of the lying (D 0 , D + ) isodoublet of charmed mesons by e + e - annihilation. A study of the recoil mass spectra against these mesons reveals the presence of more massive charmed states, the D* 0 and D* + , produced in association with the D isodoublet. Mass values and upper limits on the width of the D and D* are established, and the branching fractions for several D* decay modes are obtained. An analysis of the production and decay angular distributions shows that the D is probably a pseudoscalar state and the D* is probably a vector. Finally, upper limits are obtained for D 0 -antiD 0 mixing

Effective field theories of baryons and mesons, or, what do quarks do?

International Nuclear Information System (INIS)

Keaton, G.L.

1995-01-01

This thesis is an attempt to understand the properties of the protons, pions and other hadrons in terms of their fundamental building blocks. In the first chapter the author reviews several of the approaches that have already been developed. The Nambu-Jona-Lasinio model offers the classic example of a derivation of meson properties from a quark Lagrangian. The chiral quark model encodes much of the intuition acquired in recent decades. The author also discusses the non-linear sigma model, the Skyrme model, and the constituent quark model, which is one of the oldest and most successful models. In the constituent quark model, the constituent quark appears to be different from the current quark that appears in the fundamental QCD Lagrangian. Recently it was proposed that the constituent quark is a topological soliton. In chapter 2 the author investigates this soliton, calculating its mass, radius, magnetic moment, color magnetic moment, and spin structure function. Within the approximations used, the magnetic moments and spin structure function cannot simultaneously be made to agree with the constituent quark model. In chapter 3 the author uses a different plan of attack. Rather than trying to model the constituents of the baryon, he begins with an effective field theory of baryons and mesons, with couplings and masses that are simply determined phenomenologically. Meson loop corrections to baryon axial currents are then computed in the 1/N expansion. It is already known that the one-loop corrections are suppressed by a factor 1/N; here it is shown that the two-loop corrections are suppressed by 1/N 2 . To leading order, these corrections are exactly the same as would be calculated in the constituent quark model. This method therefore offers a different approach to the constituent quark

Recent trends in the mesonic description of nuclei

International Nuclear Information System (INIS)

Delorme, J.

1985-07-01

A survey is given of some recent developments in the domain of meson induced phenomena in nuclei. The manifestations of mesonic degrees of freedom are considered in the context of exchange currents as well as that of effective interactions. The significance of past successes is reexamined in the light of recent progress towards a QCD based nuclear theory

On the mesonic-exchange currents in the photomesic reactions

International Nuclear Information System (INIS)

Lazard, C.; Maric, Z.; Zivanovic, D.

1979-02-01

The γd→π 0 d reaction is analysed in the framework of the relativistic many-body theory with mesonic degrees of freedom explicitly present. It is shown that the mesonic correlations can be grouped into transition operators containing vertices of some elementary reactions between photon, nucleons and pions. The wave function corrections due to meson exchange currents are included in the transition operators and the S-matrix is obtained with the non relativistic deuteron wave function

Study of D(1285) → K+K-π0 decay and D(1285)- and E(1420)-mesons production in exclusive reactions, induced by π-- and K--mesons at 32.5 GeV/c

International Nuclear Information System (INIS)

Bitukov, S.I.; Viktorov, V.A.; Golovkin, S.V.

1985-01-01

D(1285) and E(1420)-mesons production in charge-exchange reactions induced by π - and K - -mesons at 32.5 GeV/c has been studied. The measured cross sections allowed one to derive limitations for the mixing angle in the axial-vector meson nonet. This means that E(1420)-meson consists mainly of strange quarks. The invariant mass distribution for the kaon pair in D(1285) → K + K - π 0 decay with statistics by an order of magnitude higher than the available data was obtained. The differential spectrum dN/dmsub(Ksup(+)Ksub(-)) analysis carried out in the delta-dominance model shows that delta(980)-meson cannot be described as a Breit-Wigner resonance with small width. The effective width for delta-meson at the point of √s=1 GeV/c 2 GITAsub(delta) is greater than 180 MeV/c 2 . It points to a strong coupling of delta-meson to hadrons

Strange, charmed and b-flavoured mesons in an effective power-law potential

International Nuclear Information System (INIS)

Barik, N.; Jena, S.N.

1981-01-01

We have shown that an effective non-coulombic power-law potenial, generating spin-dependence through scaler and vector exchanges in almost equal proportions along with zero quark-anomalous moment, which was found successful in earlier works for the fine-hyperfine splittings of heavy mesons like psi and T, can also describe very satisfactorily the S-wave hyperfine levels, M1-transition rates and electromagnetic mass difference of the strange, charmed and b-flavoured mesons. (orig.)

Strange, charmed and b-flavoured mesons in an effective power-law potential

Energy Technology Data Exchange (ETDEWEB)

Barik, N; Jena, S N [Utkal Univ., Bhubaneswar (India). Dept. of Physics

1981-05-14

We have shown that an effective non-coulombic power-law potenial, generating spin-dependence through scaler and vector exchanges in almost equal proportions along with zero quark-anomalous moment, which was found successful in earlier works for the fine-hyperfine splittings of heavy mesons like psi and T, can also describe very satisfactorily the S-wave hyperfine levels, M1-transition rates and electromagnetic mass difference of the strange, charmed and b-flavoured mesons.

The role of meson dynamics in nuclear matter saturation

International Nuclear Information System (INIS)

Goncalves, E.

1988-01-01

The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author) [pt

Measurement of the Exclusive and Inclusive Branching Fractions of $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ Decays at CDF and its Implications on the Decay Width Difference in the $B^{0}_{s}-B^{-0}_{s}$ Meson System

Energy Technology Data Exchange (ETDEWEB)

Horn, Dominik [Karlsruhe Inst. of Technology (KIT) (Germany)

2011-01-01

The purpose of this thesis is threefold: Firstly, new measurements of both the exclusive and semi-inclusive partial decay widths of $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ meson decays are presented. Secondly, the feasibility of extracting the unknown polarization components in $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ by partial reconstruction of this pseudo-scalar to vector-vector decay in a Monte Carlo driven analysis scheme is studied. Finally, based on the suggestions contributed by the theory community this study discusses how a measurement of the branching fraction of semi-inclusive decays $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ can contribute to gain insight about the relative decay width di erence in the B$0\\atop{s}$--B$0\\atop{s}$ meson system.

A quark-antiquark formation model for meson production in low transverse momentum hadron-hadron reactions

International Nuclear Information System (INIS)

Friebel, W.; Kriegel, U.; Nahnhauer, R.

1979-01-01

Introducing quark transverse momenta and masses it is proposed a 3-dimensional generalization of the quark recombination and the quark fusion model for meson production in low transverse momentum hadron-hadron reactions. A consistent description of vector meson production in proton-proton and proton-antiproton reactions from 12 - 405 GeV/c has been achieved. (author)

Lattice results for low moments of light meson distribution amplitudes

Energy Technology Data Exchange (ETDEWEB)

Arthur, R.; Boyle, P.A. [Edinburgh Univ. (United Kingdom). SUPA, School of Physics; Broemmel, D.; Flynn, J.M.; Rae, T.D.; Sachrajda, C.T.C. [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Donnellan, M.A. [NIC/DESY Zeuthen (Germany); Juettner, A. [CERN, Geneva (Switzerland). Physics Dept.

2010-12-15

As part of the UKQCD and RBC collaborations' N{sub f} = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons {pi} and K and the (longitudinally-polarised) vector mesons {rho}, K{sup *} and {phi}. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI{sup '}/MOM technique. (orig.)

Lattice Results for Low Moments of Light Meson Distribution Amplitudes

CERN Document Server

Arthur, R; Brommel, D; Donnellan, M A; Flynn, J M; Juttner, A; Rae, T D; Sachrajda, C T.C

2011-01-01

As part of the UKQCD and RBC collaborations' N_f=2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons pion and kaon and the (longitudinally-polarised) vector mesons rho, K-star and phi. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI'/MOM technique.

Lattice results for low moments of light meson distribution amplitudes

International Nuclear Information System (INIS)

Arthur, R.; Boyle, P.A.; Juettner, A.

2010-12-01

As part of the UKQCD and RBC collaborations' N f = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons π and K and the (longitudinally-polarised) vector mesons ρ, K * and φ. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI ' /MOM technique. (orig.)

Optical propagators in vector and spinor theories by path integral formalism

International Nuclear Information System (INIS)

Linares, J.

1993-01-01

The construction of an extended parabolic (wide-angle) vector and spinor wave theory is presented. For that, optical propagators in monochromatic vector light optics and monoenergetic spinor electron optics are evaluated by the path integral formalism. The auxiliary parameter method introduced by Fock and the Feynman-Dyson perturbative series are used. The proposed theory supplies, by a generalized Fermat's principle, the Mukunda-Simon-Sudarshan transformation for the passage from scalar to vector light (or spinor electron) optics in an asymptotic approximation. (author). 19 refs

Exclusive φ meson production in HERMES

International Nuclear Information System (INIS)

Golembiovskaya, Mayya

2014-03-01

In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U 1 , U 2 and U 3 which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q 2 , 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.

Exclusive φ meson production in HERMES

Energy Technology Data Exchange (ETDEWEB)

Golembiovskaya, Mayya

2014-03-15

In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U{sub 1}, U{sub 2} and U{sub 3} which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q{sup 2}, 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.

Polarisation of the ω meson in the pd→3Heω reaction at 1360 and 1450 MeV

International Nuclear Information System (INIS)

Schoenning, K.; Bargholtz, Chr.; Bashkanov, M.; Berlowski, M.; Bogoslawsky, D.; Calen, H.; Clement, H.; Demiroers, L.; Ekstroem, C.; Fransson, K.; Geren, L.; Gustafsson, L.; Hoeistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Keleta, S.; Khakimova, O.; Koch, I.

2008-01-01

The tensor polarisation of ω mesons produced in the pd→ 3 Heω reaction has been studied at two energies near threshold. The 3 He nuclei were detected in coincidence with the π 0 π + π - or π 0 γ decay products of the ω. In contrast to the case of φ-meson production, the ω mesons are found to be unpolarised. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions

Exclusive semileptonic decays of charmed and b-flavored mesons

International Nuclear Information System (INIS)

Barik, N.; Tripathy, S.K.; Kar, S.; Dash, P.C.

1997-01-01

We investigate the exclusive semileptonic decays of (B,B s ;D,D s ) mesons into less heavy as well as light mesons in a field-theoretic framework based on the independent quark model with a confining potential in scalar-vector-harmonic form. With the recoil effect properly taken into account, the present model describes consistently the semileptonic decays of charmed and b-flavored mesons, agreeing well with the experimental data. The transition form factors in the heavy to heavy decays, in particular, comply with the heavy quark symmetry relations expected from HQET. The CKM parameters extracted in this formalism are close to the existing data. The model prediction also satisfies the Isgur-Wise relation connecting the form factors of the semileptonic (B→ρeν) and that of rare radiative decay (B→ργ). copyright 1997 The American Physical Society

Pseudoscalars and vector mesons in a unitary and self-consistently broken SU(6)sub(W) scheme

International Nuclear Information System (INIS)

Roos, Mats; Toernqvist, Nils.

1979-01-01

We estimate hadronic self-energy effects to 'bare' pseudoscalar (P) and vector (V) meson states to the P→PV→P, P→VV→P, V→PP→V, V→PV→V and V→VV→V loops. We simulate higher order diagrams by consistently requiring external and internal particles to have the same mass. We find good agreement with all the experimental masses (except msub(π)), widths, and mixing angles. The 'bare' P and V states are heavy (approximately 1.26 GeV) and degenerate up to a small msub(s) - msub(u) quark mass difference term. The 'bare' coupling constants for the PPV, PVV and VVV vertices obey exact OZI rule and almost exact SU(6)sub(W) symmetry. We use a common cut-off of ksub(c.m.)approximately equal to 0.7 GeV/c corresponding to a harmonic oscillator radius of approximately equal to 0.7 fm for all SU(6)sub(W) related thresholds except for the pion. (author)

Meson-meson bound state in a 2+1 lattice QCD model with two flavors and strong coupling

International Nuclear Information System (INIS)

Faria da Veiga, Paulo A.; O'Carroll, Michael; Neto, Antonio Francisco

2005-01-01

We consider the existence of bound states of two mesons in an imaginary-time formulation of lattice QCD. We analyze an SU(3) theory with two flavors in 2+1 dimensions and two-dimensional spin matrices. For a small hopping parameter and a sufficiently large glueball mass, as a preliminary, we show the existence of isoscalar and isovector mesonlike particles that have isolated dispersion curves (upper gap up to near the two-particle threshold ∼-4lnκ). The corresponding meson masses are equal up to and including O(κ 3 ) and are asymptotically of order -2lnκ-κ 2 . Considering the zero total isospin sector, we show that there is a meson-meson bound state solution to the Bethe-Salpeter equation in a ladder approximation, below the two-meson threshold, and with binding energy of order bκ 2 ≅0.02359κ 2 . In the context of the strong coupling expansion in κ, we show that there are two sources of meson-meson attraction. One comes from a quark-antiquark exchange. This is not a meson exchange, as the spin indices are not those of the meson particle, and we refer to this as a quasimeson exchange. The other arises from gauge field correlations of four overlapping bonds, two positively oriented and two of opposite orientation. Although the exchange part gives rise to a space range-one attractive potential, the main mechanism for the formation of the bound state comes from the gauge contribution. In our lattice Bethe-Salpeter equation approach, this mechanism is manifested by an attractive distance-zero energy-dependent potential. We recall that no bound state appeared in the one-flavor case, where the repulsive effect of Pauli exclusion is stronger

J/ψ and ρ0 meson production at H1

International Nuclear Information System (INIS)

Kenyon, I.R.

1996-01-01

The production of J/ψ and ρ 0 mesons from e-p collisions, both in Deep Inelastic Scattering (DIS) and at Q 2 ∼ 0, has been studied using the H1 detector at HERA. The features of elastic ρ 0 production at Q 2 ∼ 0 are those expected from the Generalized Vector Dominance Model (VDM). However the elastic DIS ρ 0 and DIS J/ψ production as well as the elastic J/ψ production at Q 2 ∼ 0 all show features consistent with models that are inspired by perturbative QCD (pQCD). This pattern indicates that the appearance of a hard scale in vector meson production (either the quark mass, or large Q 2 ) results in a transition from VDM to pQCD. A final topic is the comparison of inelastic J/ψ production to a prediction from the photon-gluon fusion process in NLO. (author)

Non-self-conjugate mesons in a potential model with vacuum-polarization corrections

International Nuclear Information System (INIS)

Barik, N.; Jena, S.N.

1980-01-01

We present a unified approach to the study of non-self-conjugate mesons including both light and heavy mesons in the framework of the vacuum-polarization-corrected flavor-independent potential. We have found that the quark-confining potential in the form of an almost equal admixture of vector and scalar parts successfully explains the S-wave hyperfine levels of the observed light and heavy mesons. Finally we calculate the electromagnetic mass differences of the heavy-quark mesons and obtain (K-bar* 0 -K* - )=3.79 MeV, (K-bar 0 -K - )=6 MeV, (D* + /sub c/-D* 0 /sub c/)=2.4 MeV, (D + /sub c/-D 0 /sub c/)=5.8 MeV, (D* 0 /sub b/-D* - /sub b/)=3.547 MeV, and (D 0 /sub b/-D - /sub b/)=3.558 MeV

Vector manifestation and matter formed in relativistic heavy-ion processes

International Nuclear Information System (INIS)

Brown, Gerald E.; Holt, Jeremy W.; Lee, Chang-Hwan; Rho, Mannque

2007-01-01

Recent developments in our description of RHIC and related heavy-ion phenomena in terms of hidden local symmetry theories are reviewed with a focus on the novel nearly massless states in the vicinity of-both below and above-the chiral restoration temperature T c . We present complementary and intuitive ways to understand both Harada-Yamawaki's vector manifestation structure and Brown-Rho scaling-which are closely related-in terms of 'melting' of soft glues observed in lattice calculations and join the massless modes that arise in the vector manifestation (in the chiral limit) just below T c to tightly bound massless states above T c . This phenomenon may be interpreted in terms of the Beg-Shei theorem. It is suggested that hidden local symmetry theories arise naturally in holographic dual QCD from string theory, and a clear understanding of what really happens near the critical point could come from a deeper understanding of the dual bulk theory. Other matters discussed are the relation between Brown-Rho scaling and Landau Fermi-liquid fixed point parameters at the equilibrium density, its implications for 'low-mass dileptons' produced in heavy-ion collisions, the reconstruction of vector mesons in peripheral collisions, the pion velocity in the vicinity of the chiral transition point, kaon condensation viewed from the VM fixed point, nuclear physics with Brown-Rho scaling, and the generic feature of dropping masses at the RGE fixed points in generalized hidden local symmetry theories

Using anti pp annihilation to find exotic mesons

International Nuclear Information System (INIS)

Sharpe, S.R.

1987-10-01

Present data suggests that a number of mesons have been found which cannot be accommodated in standard anti qq multiplets. Theory suggests that such exotic mesons should exist in the spectrum of Quantum Chromodynamics, but provides little guide to their properties. It is argued that a high luminosity, low energy anti pp machine would be a powerful tool with which to search for such exotics

Photoproduction of vector messons off nuclei

Energy Technology Data Exchange (ETDEWEB)

Kossov, M.

1994-04-01

Vector mesons play an important role in photonuclear reactions because they carry the same quantum numbers as the incident photon. It has recently been suggested by G.E. Brown and M. Rho that the mass of vector mesons could decrease with increasing baryon density. This phenomenon would provide a physical observable for chiral symmetry ({xi}{sup S}) restoration at high baryon density, an essential non-perturbative phenomenon associated with the structure of quantum chromodynamics (QCD). According to the constituent quark model the difference between the mass of the valence quark m{sub v} and the mass of the current quark m{sub c} is expected to be proportional to the mean vacuum value of the quark condensate: m{sub v}-m{sub c} {proportional_to} ({psi}{psi}){sub v}. The mass difference appears because of chiral symmetry breaking {xi}{sup SB}. QCD sum rule calculations show that the value of this difference is about 300 MeV for all quarks. If the mean vacuum value differs from that for the hadron density in nuclei, then the constituent quark mass should be renormalized as follows: m{sub v}{sup l}=m{sub c} + ({psi}{psi})n/({psi}{psi})v {center_dot}300MeV, where the indices n correspond to nuclear matter and v to vacuum. The same conclusion was reached in a nuclear matter model based on quark degrees of freedom. Using the symmetry properties of QCD in an effective Lagrangian theory, Brown and Rho have found a scaling law for the vector meson masses at finite baryon density: M{sub N}{sup n}/M{sub N}{sup v}=M{sub V}{sup n}/M{sub V}{sup v}=f{sub {pi}}{sup n}/f{sub {pi}}{sup v}, where f{sub {pi}} is the {pi} {r_arrow}{mu}{nu} decay constant playing the role of an order parameter for the chiral symmetry restoration. At nuclear density the value of f{sub {pi}} was found to be 15-20% smaller than in vacuum. In contrast to the constituent quark model, it was found that M{sup n}/M=({sub n}/{sub v}){sup 1/3}.

In-medium relativistic kinetic theory and nucleon-meson systems

International Nuclear Information System (INIS)

Morawetz, K.; Kremp, D.

1995-01-01

Within the σ-ω model of coupled nucleonmeson systems, a generalized relativistic Lennard-Balescu-equation is presented resulting from a relativistic random phase approximation (RRPA). This provides a systematic derivation of relativistic transport equations in the frame of nonequilibrium Green's function technique including medium effects as well as fluctuation effects. It contains all possible processes due to one-meson exchange and special attention is kept to the off-shell character of the particles. As a new feature of many-particle effects, processes are possible, which can be interpreted as particle creation and annihilation due to in-medium one-meson exchange. In-medium cross sections are obtained from the generalized derivation of collision integrals, which possess complete crossing symmetries. (orig.)

Flavor symmetry breaking and meson masses

International Nuclear Information System (INIS)

Bhagwat, Mandar S.; Roberts, Craig D.; Chang Lei; Liu Yuxin; Tandy, Peter C.

2007-01-01

The axial-vector Ward-Takahashi identity is used to derive mass formulas for neutral pseudoscalar mesons. Flavor symmetry breaking entails nonideal flavor content for these states. Adding that the η ' is not a Goldstone mode, exact chiral-limit relations are developed from the identity. They connect the dressed-quark propagator to the topological susceptibility. It is confirmed that in the chiral limit the η ' mass is proportional to the matrix element which connects this state to the vacuum via the topological susceptibility. The implications of the mass formulas are illustrated using an elementary dynamical model, which includes an Ansatz for that part of the Bethe-Salpeter kernel related to the non-Abelian anomaly. In addition to the current-quark masses, the model involves two parameters, one of which is a mass-scale. It is employed in an analysis of pseudoscalar- and vector-meson bound-states. While the effects of SU(N f =2) and SU(N f =3) flavor symmetry breaking are emphasized, the five-flavor spectra are described. Despite its simplicity, the model is elucidative and phenomenologically efficacious; e.g., it predicts η-η ' mixing angles of ∼-15 deg. and π 0 -η angles of ∼1 deg

Axial vector mass spectrum and mixing angles

International Nuclear Information System (INIS)

Caffarelli, R.V.; Kang, K.

1976-01-01

Spectral sum rules of the axial-vector current and axial-vector current-pseudoscalar field are used to study the axial-vector mass spectrum and mixing angles, as well as the decay constants and mixing angles of the pseudoscalar mesons. In general, the result is quite persuasive for the existence of the Jsup(PC) = 1 ++ multiplet in which one has a canonical D-E mixing. (Auth.)

Relations de Dispersion et Diffusion des Glueballs et des Mesons dans la Theorie de Jauge U(1)(2+1) Compacte

Science.gov (United States)

Ahmed, Chaara El Mouez

Nous avons etudie les relations de dispersion et la diffusion des glueballs et des mesons dans le modele U(1)_{2+1} compact. Ce modele a ete souvent utilise comme un simple modele de la chromodynamique quantique (QCD), parce qu'il possede le confinement ainsi que les etats de glueballs. Par contre, sa structure mathematique est beaucoup plus simple que la QCD. Notre methode consiste a diagonaliser l'Hamiltonien de ce modele dans une base appropriee de graphes et sur reseau impulsion, afin de generer les relations de dispersion des glueballs et des mesons. Pour la diffusion, nous avons utilise la methode dependante du temps pour calculer la matrice S et la section efficace de diffusion des glueballs et des mesons. Les divers resultats obtenus semblent etre en accord avec les travaux anterieurs de Hakim, Alessandrini et al., Irving et al., qui eux, utilisent plutot la theorie des perturbations en couplage fort, et travaillent sur un reseau espace-temps.

Electromagnetic Meson Production in the Nucleon Resonance Region

Energy Technology Data Exchange (ETDEWEB)

Volker Burkert; T.-S. H. Lee

2004-10-01

Recent experimental and theoretical advances in investigating electromagnetic meson production reactions in the nucleon resonance region are reviewed. The article gives a description of current experimental facilities with electron and photon beams and presents a unified derivation of most of the phenomenological approaches being used to extract the resonance parameters from the data. The analyses of {pi} and {eta} production data and the resulting transition form factors for the {Delta}(1232)P{sub 33}, N(1535)S{sub 11}, N(1440)P{sub 11}, and N(1520)D{sub 13} resonances are discussed in detail. The status of our understanding of the reactions with production of two pions, kaons, and vector mesons is also reviewed.

A unified model of K- and π-mesons

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

On the foundation of an antecedent non-linear meson field theory it is suggested that the π-meson field may be described in terms of collective motions of the K-meson fields. A particular model of the K-nucleon interaction is considered whose collective π-modes have symmetrical PV coupling with the nucleon system; parity is conserved to a great extent for the π-nucleon system in the absence of strange particles. The direct K-nucleon interactions do not conserve parity; their sign and symmetry are qualitatively acceptable. The masses and coupling constants of the meson fields are determinate in terms of one universal coupling constant and a cut-off. The structure of this model suggests a natural way for the introduction of the 'spurion', describing weak interactions that violate strangeness. (author). 6 refs

Recent studies of the electromagnetic mass of mesons

International Nuclear Information System (INIS)

Yan Mulin; Gao Daoneng

1999-01-01

Recent progress in studies of the electromagnetic mass of mesons, specially a new systematic method for calculating the electromagnetic self-energies, is reviewed. Some interesting results have been obtained, for example the mass ratios of the light quarks, the generalization of Dashen's theorem to the axial-vector sector, and the electromagnetic mass anomaly of massive Yang-Mills particles

Relativistic treatment of mesonic contributions to quasielastic (e,e')

International Nuclear Information System (INIS)

Blunden, P.G.; Butler, M.N.

1988-03-01

Meson exchange currents play an important role in the description of observables in electron scattering. The authors use a relativistic model with pseudovector pion coupling to study the exchange current contributions, with emphasis on quasielastic kinematics. Starting with the Lagrangian for nucleons interacting with a scalar and vector mason along with pseudovector coupling to pions, they derive the one and two-body electromagnetic currents. They then calculate the longitudinal and transverse pieces of the quasielastic cross section for various nuclei and kinematics. The effects of meson exchange currents are found to be much more important in a relativistic model than in a non-relativistic one

Meson Spectroscopy at COMPASS

CERN Document Server

Grube, Boris

2016-11-29

The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^-\\pi^+$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. Novel analysis techniques have been...

Theory of net analyte signal vectors in inverse regression

DEFF Research Database (Denmark)

Bro, R.; Andersen, Charlotte Møller

2003-01-01

The. net analyte signal and the net analyte signal vector are useful measures in building and optimizing multivariate calibration models. In this paper a theory for their use in inverse regression is developed. The theory of net analyte signal was originally derived from classical least squares...

On rescattering in meson coherent photoproduction on nuclei

International Nuclear Information System (INIS)

Starkov, N.I.; Tsarev, V.A.

1978-01-01

Screening corrections for cross section of π deg-meson photoproduction on He nuclei were calculated: γ + 4 He → π 0 + 4 He. On the basis of the Glauber theory the effect of meson rescattering in the range of small transferred pulses (t) 2 and ''mean'' photon energies 2 2 ), determined by interference of members of one-and twofold interactions. The results are compared with those obtained by other authors

Supersymmetric gauge field theories

International Nuclear Information System (INIS)

Slavnov, A.A.

1976-01-01

The paper is dealing with the role of supersymmetric gauge theories in the quantum field theory. Methods of manipulating the theories as well as possibilities of their application in elementary particle physics are presented. In particular, the necessity is explained of a theory in which there is symmetry between Fermi and Bose fields, in other words, of the supersymmetric gauge theory for construction of a scheme for the Higgs particle connecting parameters of scalar mesons with those of the rest fields. The mechanism of supersymmetry breaking is discussed which makes it possible to remain the symmetric procedure of renormalization intact. The above mechanism of spontaneous symmetry breaking is applied to demonstrate possibilities of constructing models of weak and electromagnetic interactions which would be acceptable from the point of view of experiments. It is noted that the supersymmetric gauge theories represent a natural technique for description of vector-like models

Chiral perturbation theory for lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Baer, Oliver

2010-07-21

The formulation of chiral perturbation theory (ChPT) for lattice Quantum Chromodynamics (QCD) is reviewed. We start with brief summaries of ChPT for continuum QCD as well as the Symanzik effective theory for lattice QCD. We then review the formulation of ChPT for lattice QCD. After an additional chapter on partial quenching and mixed action theories various concrete applications are discussed: Wilson ChPT, staggered ChPT and Wilson ChPT with a twisted mass term. The remaining chapters deal with the epsilon regime with Wilson fermions and selected results in mixed action ChPT. Finally, the formulation of heavy vector meson ChPT with Wilson fermions is discussed. (orig.)

Chiral perturbation theory for lattice QCD

International Nuclear Information System (INIS)

Baer, Oliver

2010-01-01

The formulation of chiral perturbation theory (ChPT) for lattice Quantum Chromodynamics (QCD) is reviewed. We start with brief summaries of ChPT for continuum QCD as well as the Symanzik effective theory for lattice QCD. We then review the formulation of ChPT for lattice QCD. After an additional chapter on partial quenching and mixed action theories various concrete applications are discussed: Wilson ChPT, staggered ChPT and Wilson ChPT with a twisted mass term. The remaining chapters deal with the epsilon regime with Wilson fermions and selected results in mixed action ChPT. Finally, the formulation of heavy vector meson ChPT with Wilson fermions is discussed. (orig.)

Large-x dependence of νW2 in the generalized vector-dominance model

International Nuclear Information System (INIS)

Argyres, E.N.; Lam, C.S.

1977-01-01

It is well known that the usual generalized vector-meson-dominance (GVMD) model gives too large a contribution to νW 2 for large x. Various heuristic modifications, for example making use of the t/sub min/ effect, have been proposed in order to achieve a reduction of this contribution. In this paper we examine within the GVMD context whether such reductions can rigorously be achieved. This is done utilizing a potential as well as a relativistic eikonal model. We find that whereas a reduction equivalent to that of t/sub min/ can be arranged in vector-meson photoproduction, the same is not true for virtual-photon Compton scattering in such diagonal models. The reason for this difference is discussed in detail. Finally we show that the desired reduction can be obtained if nondiagonal vector-meson scattering terms are properly taken into account

Omega meson production in proton-proton collisions

International Nuclear Information System (INIS)

Schulte-Wissermann, M.; Brinkmann, K.; Dshemuchadse, S.

2005-01-01

The TOF spectrometer is an external experiment fed by the proton accelerator COSY, which is located at the Forschungszentrum Juelich, Germany. While this detector does not utilize a magnetic field for particle identification, it, however, stands out for its high acceptance (approx. 2π in the laboratory frame) and versatility. TOF measures the velocity-vectors of all charged particles, which then are used to completely reconstruct the event pattern. Due to the modular design of the TOF detector, its components can be assembled to ideally match different experimental requirements. This makes it a multipurpose device, which has shown results for many hadronic channels, starting from the pion threshold up to excess energies as high as 1GeV. One of the experimental programs is dedicated to the ω meson production. In proton-proton interactions, this channel has remained largely unstudied until the late 1990s. Then, first experimental data in the direct vicinity of the threshold and at an excess energy of ε=320 MeV became available. We have published data on ω production for two (intermediate) excess energies of ε=93 MeV and ε=173 MeV. In parallel, a considerable interest on the part of theory arose, since the reaction dynamics of ω-meson production in nucleon-nucleon collisions has an impact on many fields of modern physics. For example, there is an ongoing discussion whether 'missing resonances' may (help to) explain the phenomena observed in dense matter. These resonances would couple to the pω, but not to the pπ channel. Although predicted by many authors, until now no pω resonance was found experimentally; the strangeness content of the nucleon is still an open question. One possible key to an answer is the ratio of the total cross sections of ω to φ - mesons, which experimentally is about a factor of seven larger than simple SU predictions (often referred to as 'violation of the OZI-rule'). However, this comparison is only valid assuming similar

Backward production of the B meson in K-p interactions at 4.2 GeV/c

International Nuclear Information System (INIS)

Gavillet, Ph.; Dionisi, C.; Gurtu, A.; Hemingway, R.J.; Losty, M.J.; Marin, J.C.; Mazzucato, M.; Montanet, L.; Pagiola, E.; Blokzijl, R.; Jongejans, B.; Kluyver, J.C.; Massaro, G.G.G.; Engelen, J.J.; Vergeest, J.S.M.; Zralek, M.; Foster, B.; Grossmann, P.; Wells, J.

1978-01-01

The backward production of the B(1235) meson is studied in the reaction K - p → Σ - π + ω. This reaction is observed in the final state Σ - π + π + π - π 0 . A π + ω mass enhancement is visible in the region of the B meson for events with small mod(u)(K - → Σ - ) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K - p → Σ - B + at 4.15 GeV/c incident K - momentum is (3.2 +- 0.5) μb. The backward production of the B meson is compared with similar baryon exchange productions of the A 1 and C(Q 1 ) axial vector mesons observed in the same experiment. (Auth.)

Excited scalar and pseudoscalar mesons in the extended linear sigma model

Energy Technology Data Exchange (ETDEWEB)

Parganlija, Denis [Technische Universitaet Wien, Institut fuer Theoretische Physik, Vienna (Austria); Giacosa, Francesco [Jan Kochanowski University, Institute of Physics, Kielce (Poland); Johann Wolfgang Goethe-Universitaet, Institut fuer Theoretische Physik, Frankfurt am Main (Germany)

2017-07-15

We present an in-depth study of masses and decays of excited scalar and pseudoscalar anti qq states in the Extended Linear Sigma Model (eLSM). The model also contains ground-state scalar, pseudoscalar, vector and axial-vector mesons. The main objective is to study the consequences of the hypothesis that the f{sub 0}(1790) resonance, observed a decade ago by the BES Collaboration and recently by LHCb, represents an excited scalar quarkonium. In addition we also analyse the possibility that the new a{sub 0}(1950) resonance, observed recently by BABAR, may also be an excited scalar state. Both hypotheses receive justification in our approach although there appears to be some tension between the simultaneous interpretation of f{sub 0}(1790)/a{sub 0}(1950) and pseudoscalar mesons η(1295), π(1300), η(1440) and K(1460) as excited anti qq states. (orig.)

Meson-meson scattering in lattice QED2+1

International Nuclear Information System (INIS)

Fiebig, H.R.; Woloshyn, R.M.

1993-01-01

Scattering phase shifts of a meson-meson system in staggered 3-dimensional lattice QED are computed. The main task of the simulation is to obtain a discrete set of two-body energy levels. These are extracted from a 4-point time correlation matrix and then used to obtain scattering phase shifts. The results for the l = 0 and l = 2 partial waves are consistent with short-range repulsion and intermediate-range attraction of the residual meson-meson interaction. (orig.)

P-odd effects in the e-d scattering in the vector-like theories

International Nuclear Information System (INIS)

Gakh, G.I.

1979-01-01

P-odd effects in elastic electron-deuteron scattering, due to the weak neutral currents, are analyzed in the framework of the vector-like theories. Considered is the case of the most general form of the P-invariance breaking in the elastic e - d scattering amplitude in both the leptonic and hadronic vertices. It is found that in the vector-like theories the parity violation in the electro-deuteron elastic scattering is confined in the hadronic vertex, while in the Weinberg-Salam model it is confined in the leptonic vertex. In the vector-like theories the asymmetry in the scattering of longitudinally polarized electrons by nonpolarized deuterons depends on the electromagnetic and weak form factors of a deuteron, whereas in the Weinberg-Salam model it does not depend on the structure of the deuteron. In the Weinberg-Salam model the asymmetry is independent on the T-violating form factors of the deuteron, whereas such a dependence is present in the vector-like theories

Coherent production of ρ - mesons in charged current antineutrino-neon interactions in BEBC

Science.gov (United States)

Marage, P.; Aderholz, M.; Allport, P.; Armenise, N.; Baton, J. P.; Berggren, M.; Bertrand, D.; Brisson, V.; Bullock, F. W.; Burkot, W.; Calicchio, M.; Clayton, E. F.; Coghen, T.; Cooper-Sarkar, A. M.; Erriquez, O.; Fitch, P. J.; Guy, J.; Hamisi, F.; Hulth, P. O.; Jones, G. T.; Kasper, P.; Katz, U. F.; Klein, H.; Matsinos, E.; Middleton, R. P.; Miller, D. B.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; O'Neale, S. W.; Parker, M. A.; Petiau, P.; Sacton, J.; Sansum, R. A.; Schmitz, N.; Simopoulou, E.; Vallée, C.; Varvell, K.; Vayaki, A.; Venus, W.; Wachsmuth, H.; Wells, J.; Wittek, W.

1987-09-01

Coherent production of ρ - mesons in charged current antineutrino interactions on neon nuclei is studied in the BEBC bubble chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25)·10-40 cm2 per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model.

Coherent production of ρ- mesons in charged current antineutrino-neon interactions in BEBC

International Nuclear Information System (INIS)

Marage, P.; Bertrand, D.; Sacton, J.; Aderholz, M.; Katz, U.F.; Schmitz, N.; Wittek, W.; Allport, P.; Varvell, K.; Wells, J.; Baton, J.P.; Kasper, P.; Neveu, M.; Clayton, E.F.; Hamisi, F.; Miller, D.B.; Mobayyen, M.M.; Cooper-Sarkar, A.M.; Guy, J.; Venus, W.; Klein, H.; Morrison, D.R.O.; Parker, M.A.; Wachsmuth, H.; Matsinos, E.; Simopoulou, E.; Vayaki, A.

1987-01-01

Coherent production of ρ - mesons in charged antineutrino interactions on neon nuclei is studied in the BEBC bubbler chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25).10 -40 cm 2 per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model. (orig.)

Study of open-charm 0{sup +} states in unitarized chiral effective theory with one-loop potentials

Energy Technology Data Exchange (ETDEWEB)

Du, Meng-Lin [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Guo, Feng-Kun [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Yao, De-Liang [Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Instituto de Fisica Corpuscular (Centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Valencia (Spain)

2017-11-15

Chiral potentials are derived for the interactions between Goldstone bosons and pseudo-scalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for S-wave scattering in the threshold region. This validates the use of D*-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with J{sup P} = 0{sup +} as poles of the S-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well. (orig.)

Color transparency in incoherent electroproduction of ρ mesons off nuclei

International Nuclear Information System (INIS)

Nemchik, J.; Kopeliovich, B. Z.; Potashnikova, I. K.

2013-01-01

Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of ρ meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q 2 . Motivated by the last CLAS data we predict the A, Q 2 and l c dependence of nuclear transparency for ρ 0 mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.

Color transparency in incoherent electroproduction of {rho} mesons off nuclei

Energy Technology Data Exchange (ETDEWEB)

Nemchik, J. [Institute of Experimental Physics SAS, Watsonova 47, 04001 Kosice, Slovakia and Czech Technical University, FNSPE, Brehova 7, 11519 Praque (Czech Republic); Kopeliovich, B. Z.; Potashnikova, I. K. [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile)

2013-04-15

Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of {rho} meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q{sup 2}. Motivated by the last CLAS data we predict the A, Q{sup 2} and l{sub c} dependence of nuclear transparency for {rho}{sup 0} mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.

Meson-nucleus potentials and the search for meson-nucleus bound states

Science.gov (United States)

Metag, V.; Nanova, M.; Paryev, E. Ya.

2017-11-01

Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K+ ,K0 ,K- , η ,η‧ , ω, and ϕ mesons are presented and compared with theoretical predictions. The interaction of K+ and K0 mesons with nuclei is found to be weakly repulsive, while the K- , η ,η‧ , ω and ϕ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η‧ mesons.

Gauge theories of Yang-Mills vector fields coupled to antisymmetric tensor fields

International Nuclear Information System (INIS)

Anco, Stephen C.

2003-01-01

A non-Abelian class of massless/massive nonlinear gauge theories of Yang-Mills vector potentials coupled to Freedman-Townsend antisymmetric tensor potentials is constructed in four space-time dimensions. These theories involve an extended Freedman-Townsend-type coupling between the vector and tensor fields, and a Chern-Simons mass term with the addition of a Higgs-type coupling of the tensor fields to the vector fields in the massive case. Geometrical, field theoretic, and algebraic aspects of the theories are discussed in detail. In particular, the geometrical structure mixes and unifies features of Yang-Mills theory and Freedman-Townsend theory formulated in terms of Lie algebra valued curvatures and connections associated to the fields and nonlinear field strengths. The theories arise from a general determination of all possible geometrical nonlinear deformations of linear Abelian gauge theory for one-form fields and two-form fields with an Abelian Chern-Simons mass term in four dimensions. For this type of deformation (with typical assumptions on the allowed form considered for terms in the gauge symmetries and field equations), an explicit classification of deformation terms at first-order is obtained, and uniqueness of deformation terms at all higher orders is proven. This leads to a uniqueness result for the non-Abelian class of theories constructed here

Q.C.D. predictions for the forward photoproduction of heavy vector mesons

International Nuclear Information System (INIS)

Navelet, H.; Peschanski, R.

1984-03-01

From the inelastic QantiQ-Nucleon cross section, we get predictions for the forward photoproduction of heavy QantiQ mesons by using V.D.M. and the optical theorem. These cross sections are computed from perturbative Q.C.D. through gluon radiation mechanism

Phenomenological study of helicity amplitudes of high energy exclusive leptoproduction of the ρ meson

International Nuclear Information System (INIS)

Anikin, I. V.; Besse, A.; Ivanov, D. Yu.; Pire, B.; Szymanowski, L.; Wallon, S.

2011-01-01

We apply a previously developed scheme to consistently include the twist-3 distribution amplitudes for transversely polarized ρ mesons in order to evaluate, in the framework of k T factorization, the helicity amplitudes for exclusive leptoproduction of a light vector meson, at leading order in α s . We compare our results with high energy experimental data for the ratios of helicity amplitudes T 11 /T 00 and T 01 /T 00 and get a good description of the data.

Bridging Economic Theory Models and the Cointegrated Vector Autoregressive Model

DEFF Research Database (Denmark)

Møller, Niels Framroze

2008-01-01

Examples of simple economic theory models are analyzed as restrictions on the Cointegrated VAR (CVAR). This establishes a correspondence between basic economic concepts and the econometric concepts of the CVAR: The economic relations correspond to cointegrating vectors and exogeneity in the econo......Examples of simple economic theory models are analyzed as restrictions on the Cointegrated VAR (CVAR). This establishes a correspondence between basic economic concepts and the econometric concepts of the CVAR: The economic relations correspond to cointegrating vectors and exogeneity...... are related to expectations formation, market clearing, nominal rigidities, etc. Finally, the general-partial equilibrium distinction is analyzed....

Null vectors in superconformal quantum field theory

International Nuclear Information System (INIS)

Huang Chaoshang

1993-01-01

The superspace formulation of the N=1 superconformal field theory and superconformal Ward identities are used to give a precise definition of fusion. Using the fusion procedure, superconformally covariant differential equations are derived and consequently a complete and straightforward algorithm for finding null vectors in Verma modules of the Neveu-Schwarz algebra is given. (orig.)

Properties of the ρ meson in dense nuclear matter

International Nuclear Information System (INIS)

Herrmann, M.

1992-05-01

In order to reach a description of the ρ meson, which is in accordance with the principles of the gauge invariance of the electromagnetic interaction, the vector-dominance hypothesis, and the unitarity a model for the ρ meson in the vacuum is developed. Thereafter follows the calculation of the properties of the ρ meson in nuclear matter. First the connection between the spectral function of the ρ meson and the dilepton production rate for an equilibrium state is derived. Then the model for the pion in nuclear matter is described. Following approximations are applied: The description of the pion-baryon interaction pursues non-relativistically and both the width of the delta resonance and the short-range repulsive delta-nucleon interaction is neglected. The self-energy of the ρ meson in nuclear matter following from this description is formally derived from the requirement to couple the ρ meson to a conserved current. The corrections for the 3-point and 4-point vertex resulting from this are calculated and discussed. Thereafter the physical consequences of the changed self-energy of the ρ meson in nuclear matter are considered. By means of the spectral function it is shown that up to the two-fold of the ground-state density the position of the resonance is nearly not changed. At still higher densities the resonances is a little shifted to higher energies. In the range of an invariant mass of about 400 meV a strong increasement concentrated on a small range results. This is caused by coupling to a naked delta-hole state and a pion. Finally the possibilities are discussed to apply the results of this thesis to the prediction of experimental data. Thereby it is proved to be necessary to base on a simulation of the heavy ion reaction. (orig./HSI) [de

Precision spectroscopy at COMPASS: Observation of a new (exotic) light axial vector meson and a deeper look into decay dynamics

CERN Multimedia

CERN. Geneva

2013-01-01

High statistical accuracy has triggered the development of innovative analysis schemes not possible in previous experiments and lead to the discovery of new hadronic states. Among these is the observation of a new light (possibly exotic) axial vector meson, the interpretation of which is still open. In addition we have analyzed the pi-pi S-wave content in exclusive 3pi-events. As a result of our analysis also the interpretation of resonance structures can now be clarified using the variation of production rates with the four momentum transfer, allowing to identify resonant and non-resonant components in the spectra. In addition to the 3pi final states we will also give an overview on results obtained with other particles forming the final state and present an outlook on forthcoming results.

Mesons from (non) Abelian T-dual backgrounds

Energy Technology Data Exchange (ETDEWEB)

Itsios, Georgios [Instituto de Física Teórica, UNESP-Universidade Estadual Paulista, R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Department of Physics, University of Oviedo,Avda. Calvo Sotelo 18, 33007 Oviedo (Spain); Núñez, Carlos [Department of Physics, Swansea University,Swansea SA2 8PP (United Kingdom); Zoakos, Dimitrios [Centro de Física do Porto, Universidade do Porto,Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

2017-01-03

In this work we study mesonic excitations in a Quantum Field Theory dual to the non Abelian T-dual of AdS{sub 5}×S{sup 5}, using a D6 brane probe on the Sfetsos-Thompson background. Before and after the duality, we observe interesting differences between the spectra and interpret them. The spectrum of masses and the interactions between mesonic excitations teach valuable lessons about the character of non-Abelian T-duality and its implications for Holography. The case of Abelian T-duality is also studied.

Properties of nuclear and neutron matter in a relativistic Hartree-Fock theory

International Nuclear Information System (INIS)

Horowitz, C.J.; Serot, B.D.

1983-01-01

Relativistic-Hartree-Fock (HF) equations are derived for an infinite system of mesons and baryons in the framework of a renormalizable relativistic quantum field theory. The derivation is based on a diagrammatic approach and Dyson's equation for the baryon propagator. The result is a set of coupled, nonlinear integral equations for the baryon self-energy with a self-consistency condition on the single-particle spectrum. The HF equations are solved for nuclear and neutron matter in the Walecka model, which contains neutral scalar and vector mesons. After renormalizing model parameters to reproduce nuclear matter saturation properties, HF results at low to moderate densities are similar to those in the mean-field (Hartree) approximation. Self-consistent exchange corrections to the Hartree equation of state become negligible at high densities. Rho- and pi-meson exchanges are incorporated using a renormalizable gauge-theory model. A chiral transformation of the lagrangian is used to replace the pseudoscalar πN coupling with a pseudovector coupling, for which one-pion exchange is a reasonable first approximation. This transformation maintains the model's renormalizability so that corrections may be evaluated. Pion exchange has a small effect on the HF results of the Walecka model and brings HF results in closer in closer agreement with the mean-field theory. The diagrammatic techniques used here retain the mesonic degrees of freedom and are simple enough to be extended to more refined self-consistent approximations. (orig.)

Meson-induced correlations of nucleons in nuclear Compton scattering

International Nuclear Information System (INIS)

Huett, M.; Milstein, A.I.

1998-01-01

The nonresonant (seagull) contribution to the nuclear Compton amplitude at low energies is strongly influenced by nucleon correlations arising from meson exchange. We study this problem in a modified Fermi gas model, where nuclear correlation functions are obtained with the help of perturbation theory. The dependence of the mesonic seagull amplitude on the nuclear radius is investigated and the influence of a realistic nuclear density on this amplitude is discussed. We found that different form factors appear for the static part (proportional to the enhancement constant κ) of the mesonic seagull amplitude and for the parts, which contain the contribution from electromagnetic polarizabilities. copyright 1998 The American Physical Society

Singular vectors of Malikov-Fagin-Fux in topological theories

International Nuclear Information System (INIS)

Semikhatov, A.M.

1993-01-01

Coincidence of singular vectors in relation to the sl(2) Katza-Mudi algebra and the algebra of the N=2 (twisted) supersymmetry is established. On the base of the Kazama-Suzuki simplest model is obtained a representation for the sl(2) currents in terms of an interacting with mater gravitation. From the Malikov-Fagin-Fux formulae for the sl(2) singular currents is obtained the general expression for singular vectors in topological theories

Parallel/vector algorithms for the spherical SN transport theory method

International Nuclear Information System (INIS)

Haghighat, A.; Mattis, R.E.

1990-01-01

This paper discusses vector and parallel processing of a 1-D curvilinear (i.e. spherical) S N transport theory algorithm on the Cornell National SuperComputer Facility (CNSF) IBM 3090/600E. Two different vector algorithms were developed and parallelized based on angular decomposition. It is shown that significant speedups are attainable. For example, for problems with large granularity, using 4 processors, the parallel/vector algorithm achieves speedups (for wall-clock time) of more than 4.5 relative to the old serial/scalar algorithm. Furthermore, this work has demonstrated the existing potential for the development of faster processing vector and parallel algorithms for multidimensional curvilinear geometries. (author)

Light-Meson Spectroscopy at COMPASS

CERN Document Server

Krinner, Fabian

2017-01-01

The goal of the COMPASS experiment at CERN is to study the structure and spectroscopy of hadrons. The two-stage spectrometer has large acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range of reactions. Light mesons are studied with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of $190\\,\\text{GeV}/c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between $0.1$ and $1.0\\,(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^+\\pi^-$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. The findings are confirmed by the analysis of the $\\pi^-\\pi^0\\pi^...

Effective mass of omega meson and NNω interaction at finite temperature and density

International Nuclear Information System (INIS)

Gao, S.; Su, R.; Yu, P.K.N.

1994-01-01

By means of the thermofield dynamical theory, the effective mass of omega meson is calculated by summing the bubble diagrams. It is found that the formula for the effective mass of the ρ meson can also be used to describe the ω meson in the low density region, but the parameter n and the critical temperature T c depend on the density. The temperature and density dependence of one omega exchage potential of nucleon-nucleon interaction are given. The conjecture of Brown and Rho about the effective masses of mesons is discussed

Masses of S and P wave mesons and pseudoscalar decay constants ...

Indian Academy of Sciences (India)

interactions are perturbatively incorporated with the confinement energy to get the respective vector- pseudoscalar meson mass differences. Here we employ the same parametrization and model param- eters as used in a recent study of low-lying hadron masses and leptonic decay widths. The results are being compared ...

Nonleptonic decay of charmed mesons and chiral lagrangians

International Nuclear Information System (INIS)

Kalinovskij, Yu.L.; Pervushin, V.N.

1978-01-01

Nonleptonic decays of charmed mesons in chiral theory are considered. The lagrangian of strong interaction is taken to be invariant under the SU(4)xSU(4) group. Symmetry breaking is chosen according to the (4,4sup(*))+(4sup(*),4) simplest representation of the SU(4)xSU(4) group. The lagrangian of weak interaction is taken in the ''current x current'' form and satisfies exactly the rule probabilities of decays for D and F mesons are compared with available experimental data

Decay constants of heavy mesons in the relativistic potential model with velocity dependent corrections

International Nuclear Information System (INIS)

Avaliani, I.S.; Sisakyan, A.N.; Slepchenko, L.A.

1992-01-01

In the relativistic model with the velocity dependent potential the masses and leptonic decay constants of heavy pseudoscalar and vector mesons are computed. The possibility of using this potential is discussed. 11 refs.; 4 tabs

Bridging Economic Theory Models and the Cointegrated Vector Autoregressive Model

DEFF Research Database (Denmark)

Møller, Niels Framroze

2008-01-01

Examples of simple economic theory models are analyzed as restrictions on the Cointegrated VAR (CVAR). This establishes a correspondence between basic economic concepts and the econometric concepts of the CVAR: The economic relations correspond to cointegrating vectors and exogeneity in the econo......Examples of simple economic theory models are analyzed as restrictions on the Cointegrated VAR (CVAR). This establishes a correspondence between basic economic concepts and the econometric concepts of the CVAR: The economic relations correspond to cointegrating vectors and exogeneity...... parameters of the CVAR are shown to be interpretable in terms of expectations formation, market clearing, nominal rigidities, etc. The general-partial equilibrium distinction is also discussed....

The nuclear equation of state in effective relativistic field theories and pion yields in heavy-ion collisions

International Nuclear Information System (INIS)

Schoenhofen, M.; Cubero, M.; Gering, M.; Sambataro, M.; Feldmeier, H.; Noerenberg, W.

1989-06-01

Within the framework of relativistic field theory for nucleons, deltas, scalar and vector mesons, a systematic study of the nuclear equation of state and its relation to pion yields in heavy-ion collisions is presented. Not the compressibility but the effective nucleon mass at normal nuclear density turns out to be the most sensitive parameter. Effects from vaccum fluctuations are well modelled within the mean-field no-sea approximation by self-interaction terms for the scalar meson field. Incomplete thermalization in the fireball may be the reason for the low pion yields observed in heavy-ion collisions. (orig.)

The Scalar, Vector and Tensor Fields in Theory of Elasticity and Plasticity

Directory of Open Access Journals (Sweden)

František FOJTÍK

2014-06-01

Full Text Available This article is devoted to an analysis of scalar, vector and tensor fields, which occur in the loaded and deformed bodies. The aim of this article is to clarify and simplify the creation of an understandable idea of some elementary concepts and quantities in field theories, such as, for example equiscalar levels, scalar field gradient, Hamilton operator, divergence, rotation and gradient of vector or tensor and others. Applications of those mathematical terms are shown in simple elasticity and plasticity tasks. We hope that content of our article might help technicians to make their studies of necessary mathematical chapters of vector and tensor analysis and field theories easier.

Generalized structure of hadron-quark vertex function in Bethe-Salpeter framework: applications to leptonic decays of V-mesons

Energy Technology Data Exchange (ETDEWEB)

Bhatnagar, Shashank [Department of Physics, Addis Ababa University, PO Box 101739, Addis Ababa (Ethiopia); Li Shiyuan [Department of Physics, Shandong University, Jinan, 250100 (China)

2006-07-15

We employ the framework of the Bethe-Salpeter equation under a covariant instantaneous ansatz to study the leptonic decays of vector mesons. The structure of the hadron-quark vertex function {gamma} is generalized to include various Dirac covariants (other than i{gamma} . {epsilon}) from their complete set. They are incorporated in accordance with a naive power counting rule order-by-order in powers of the inverse of the meson mass. The decay constants for {rho}, {omega} and {phi} mesons are calculated with the incorporation of leading-order covariants.

Generalized structure of hadron-quark vertex function in Bethe-Salpeter framework: applications to leptonic decays of V-mesons

International Nuclear Information System (INIS)

Bhatnagar, Shashank; Li Shiyuan

2006-01-01

We employ the framework of the Bethe-Salpeter equation under a covariant instantaneous ansatz to study the leptonic decays of vector mesons. The structure of the hadron-quark vertex function Γ is generalized to include various Dirac covariants (other than iγ . ε) from their complete set. They are incorporated in accordance with a naive power counting rule order-by-order in powers of the inverse of the meson mass. The decay constants for ρ, ω and φ mesons are calculated with the incorporation of leading-order covariants

Effect of δ meson and ρ-ω cross couplings in effective field theory motivated Lagrangian approach

International Nuclear Information System (INIS)

Jagota, R.K.; Dhiman, S.K.; Sharma, B.K.; Arumugam, P.; Patra, S.K.

2005-01-01

It is shown that the self and cross couplings of ω meson plays an important role to make the nuclear equation of state (EOS) softer. The parameter set G2, obtained from the effective field theory motivated Lagrangian (E-RMF) approach, is very successful to reproduce the nuclear matter properties including the structure of neutron star as well as of finite nuclei. The motivation of the present report is to see the effects of these terms in the E-RMF Lagrangian on infinite nuclear matter as well as finite nuclei

Lattice Calculation of D- and B-meson Semileptonic Decays, using the Clover Action at beta=6.0 on APE

CERN Document Server

Allton, C R; Lubicz, V; Martinelli, G; Rapuano, F; Stella, N; Vladikas, A; Bartoloni, A; Battista, C; Cabasino, S; Cabibbo, Nicola; Panizzi, E; Paolucci, P S; Sarno, R; Todesco, G M; Torelli, M; Vicini, P

1995-01-01

We present the results of a high statistics lattice calculation of hadronic form factors relevant for $D-$ and $B-$meson semi-leptonic decays into light pseudoscalar and vector mesons. The results have been obtained by averaging over 170 gauge field configurations, generated in the quenched approximation, at $\\beta=6.0$, on a $18^3 \\times 64$ lattice, using the $O(a)$-improved SW-Clover action.From the study of the matrix element $$, we obtain $f_+ (0)=0.78\\pm 0.08$ and from the matrix element $$ we obtain $V(0)=1.08\\pm 0.22$, $A_1(0)=0.67\\pm 0.11$ and $A_2(0)=0.49\\pm 0.34$. We also obtain the ratios $V(0)/A_1(0)=1.6\\pm 0.3$ and $A_2(0)/A_1(0)= 0.7\\pm 0.4$. Our predictions for the different form factors are in good agreement with the experimental data, although, in the case of $A_2(0)$, the errors are still too large to draw any firm conclusion. With the help of the Heavy Quark Effective Theory (HQET) we have also extrapolated the lattice results to $B$-meson decays. The form factors follow a behaviour compat...

Vector entropy imaging theory with application to computerized tomography

International Nuclear Information System (INIS)

Wang Yuanmei; Cheng Jianping; Heng, Pheng Ann

2002-01-01

Medical imaging theory for x-ray CT and PET is based on image reconstruction from projections. In this paper a novel vector entropy imaging theory under the framework of multiple criteria decision making is presented. We also study the most frequently used image reconstruction methods, namely, least square, maximum entropy, and filtered back-projection methods under the framework of the single performance criterion optimization. Finally, we introduce some of the results obtained by various reconstruction algorithms using computer-generated noisy projection data from the Hoffman phantom and real CT scanner data. Comparison of the reconstructed images indicates that the vector entropy method gives the best in error (difference between the original phantom data and reconstruction), smoothness (suppression of noise), grey value resolution and is free of ghost images. (author)

Renormalizable massive charged vector-boson theory without spontaneous symmetry breakdown

International Nuclear Information System (INIS)

Mac, E.

1977-01-01

A renormalizable and unitary theory of massive charged vector bosons is proposed. This theory has a similarity with the Georgi-Glashow theory, the difference being that in the former the Lagrangian does not contain the potential term in the scalar fields necessary in theories with spontaneous symmetry breaking. The mass M > 0 of the charged vector bosons are introduced in the Lagrangian in such a way that the Lagrangian is still invariant under a ''distorted'' local gauge symmetry. This Lagrangian is studied in the generalized renormalizable gauge (gauge R /sub xi/), by means of the Lagrange multiplier formalism. In this way, the fictitious Lagrangian that restores unitarity to the theory can be constructed. The fictitious Lagrangian constructed using the Lagrange multiplier formalism is compared to the one obtained due to the variation of the gauge condition under the gauge transformations. The renormalizability of this theory is studied and the Ward-Takahaski identities are derived; these identities are checked by explicit calculations. Using the Becchi-Rouet-Stora transformation, one can obtain the equation satisfied by the renormalized Lagrangian; solving this equation the most general form of the renormalized Lagrangian is obtained. Also the classical solutions of this kind of theories are studied. Solutions are found suggesting the presence of dyons

Quasi-renormalization of the axial vector model

International Nuclear Information System (INIS)

Schweda, M.

1979-01-01

Using the regulator-free BPHZL renormalization scheme the problem of anomalies in a massive axial vector meson model is reinvestigated. The Adler-Bardeen-Bell-Jackiw anomaly introduces some impressive modifications: the nontrivial self-energy and the counterterm of the longitudinal part of the axial vector field depend on the anomaly via the anomalous Ward identity. The investigations are based on a Fermi-type gauge. (author)

Next-to-leading order QCD corrections to the decay of Higgs to vector meson and Z boson

Science.gov (United States)

Sun, Qing-Feng; Wang, An-Min

2018-02-01

The exclusive decay of the Higgs boson to a vector meson (J/ψ or Υ(1S)) and Z boson is studied in this work. The decay amplitudes are separated into two parts in a gauge invariant manner. The first part comes from the direct coupling of the Higgs boson to the charm (bottom) quark and the other from the HZZ* or the loop-induced HZ γ* vertexes in the standard model. While the branching ratios from the direct channel are much smaller than those of the indirect channel, their interference terms give nontrivial contributions. We further calculate the QCD radiative corrections to both channels, which reduce the total branching ratios by around 20% for both (J/ψ or Υ(1S)) production. Our results provide a possible chance to check the SM predictions of the {{Hc}}\\bar{{{c}}}({{Hb}}\\bar{{{b}}}) coupling and to seek for hints of new physics at the High Luminosity LHC or future hadron colliders. Supported by National Natural Science Foundation of China (11375168)

Precision Measurements of the Proton Electromagnetic Form Factors in the Time-Like Region and Vector Meson Spectroscopy

CERN Multimedia

2002-01-01

The aim of this experiment is to measure with precision the electromagnetic form factors of the proton in the time-like region via the reaction: .ce @*p @A e|+e|- with antiprotons of momenta between 0 and 2 GeV/c. Up to @= 800 MeV/c, a continuous energy scan in @= 2 MeV (@]s) bins will be performed. The form factor !G(E)! and !G(M)! will be determined separately since large statistics can be collected with LEAR antiproton beams, so that angular distributions can be obtained at many momenta.\\\\ \\\\ In addition, e|+e|- pairs produced via the reaction: .ce @*p @A V|0 + neutrals, .ce !@A e|+e|- where the antiprotons are at rest, will be detected allowing the vector meson mass spectrum between @= 1 GeV and @= 1.7 GeV to be obtained with high statistics and in one run. \\\\ \\\\ The proposed apparatus consists of a central detector, surrounded by a gas Cerenkov counter, wire chambers, hodoscopes, and an electromagnetic calorimeter. The central detector consists of several layers of proportional chambers around a liquid-h...

Relativistic stars in vector-tensor theories

Science.gov (United States)

Kase, Ryotaro; Minamitsuji, Masato; Tsujikawa, Shinji

2018-04-01

We study relativistic star solutions in second-order generalized Proca theories characterized by a U (1 )-breaking vector field with derivative couplings. In the models with cubic and quartic derivative coupling, the mass and radius of stars become larger than those in general relativity for negative derivative coupling constants. This phenomenon is mostly attributed to the increase of star radius induced by a slower decrease of the matter pressure compared to general relativity. There is a tendency that the relativistic star with a smaller mass is not gravitationally bound for a low central density and hence is dynamically unstable, but that with a larger mass is gravitationally bound. On the other hand, we show that the intrinsic vector-mode couplings give rise to general relativistic solutions with a trivial field profile, so the mass and radius are not modified from those in general relativity.

Search for Odderon induced contributions to exclusive Meson Photoproduction at HERA

International Nuclear Information System (INIS)

Olsson, J.

2001-01-01

A search for exclusive photoproduction of π 0 , f 2 (1270) and a 2 (1320), induced by Odderon exchange, was performed using multi-photon final states. No signal was found. Upper limits for the cross sections are below the predictions of a model based on non-perturbative QCD. Exclusive ω and ωπ 0 photoproduction is observed in three and five photon final states, at levels consistent with the expectations from Pomeron exchange and consistent with other observations of exclusive vector and axial vector meson photoproduction

Zero sound velocity in π, ρ mesons at different temperatures

International Nuclear Information System (INIS)

Dey, J.; Dey, M.; Tomio, L.; Araujo, C.F. de Jr.

1994-07-01

Sharp transitions are perhaps absent in QCD, so that one looks for physical quantities which may reflect the phase change. One such quantity is the sound velocity which was shown in lattice theory to become zero at the transition point for pure glue. We show that even in a simple bag model the sound velocity goes to zero at temperature T=T ν ≠ 0 and that the numerical value of this T ν depends on the nature of the meson. The average thermal energy of mesons go linearly with T near T ν , with much smaller slope for the pion. The T ν - s can be connected with the Boltzmann temperatures obtained from transverse momentum spectrum of these mesons in heavy ion collision at mid-rapidity. It would be interesting to check the presence of different T ν - s in present day finite T lattice theory. (author). 22 refs, 1 fig., 2 tabs

Particle states of a quantized meson field

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

A simple non-linear field theory is considered as the model for a recently proposed classical field theory of mesons and their particle sources. Quantization may be made according to canonical procedures; the problem is to show the existence of quantum states corresponding with the particle-like solutions of the classical field equations. A plausible way to do this is suggested. (author). 5 refs

Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter

International Nuclear Information System (INIS)

Hrayr Matevosyan

2007-01-01

Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green's functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme

The effect of higher order different meson exchange nucleon-nucleon interactions on the three-nucleon binding energy coupling problem

International Nuclear Information System (INIS)

Osman, A.; Ramadan, S.

1989-01-01

Faddeev equations of bound three-nucleon system are presented as a set of integral equations. To solve them, a sutable form of the nucleon-nucleon interactions is used: with the exchange of a scalar meson, a pseudoscalar meson and a massless vector meson. Higher orders of these different meson exchanges in the nucleon-nucleon interactions have been taken into account. With these nuclear forces and nucleon-nucleon interactions, the three-nucleon binding energy is calculated by solving the Faddeev integral equations. The obtained value of the three-nucleon binding energy is 8.441 MeV. The inclusion of the higher order terms of the different meson exchange in the nuclear nucleon-nucleon interaction is found to affect the three-nucleon binding by about 3.92%. 3 figs., 16 refs

Constraints and stability in vector theories with spontaneous Lorentz violation

International Nuclear Information System (INIS)

Bluhm, Robert; Gagne, Nolan L.; Potting, Robertus; Vrublevskis, Arturs

2008-01-01

Vector theories with spontaneous Lorentz violation, known as bumblebee models, are examined in flat spacetime using a Hamiltonian constraint analysis. In some of these models, Nambu-Goldstone modes appear with properties similar to photons in electromagnetism. However, depending on the form of the theory, additional modes and constraints can appear that have no counterparts in electromagnetism. An examination of these constraints and additional degrees of freedom, including their nonlinear effects, is made for a variety of models with different kinetic and potential terms, and the results are compared with electromagnetism. The Hamiltonian constraint analysis also permits an investigation of the stability of these models. For certain bumblebee theories with a timelike vector, suitable restrictions of the initial-value solutions are identified that yield ghost-free models with a positive Hamiltonian. In each case, the restricted phase space is found to match that of electromagnetism in a nonlinear gauge

Hairy black hole solutions in U(1) gauge-invariant scalar-vector-tensor theories

Science.gov (United States)

Heisenberg, Lavinia; Tsujikawa, Shinji

2018-05-01

In U (1) gauge-invariant scalar-vector-tensor theories with second-order equations of motion, we study the properties of black holes (BH) on a static and spherically symmetric background. In shift-symmetric theories invariant under the shift of scalar ϕ → ϕ + c, we show the existence of new hairy BH solutions where a cubic-order scalar-vector interaction gives rise to a scalar hair manifesting itself around the event horizon. In the presence of a quartic-order interaction besides the cubic coupling, there are also regular BH solutions endowed with scalar and vector hairs.

A Study of Spin Alignment of $\\rho(770)^{\\pm}$ and $\\omega(782)$ Mesons in Hadronic $Z^{0}$ Decays

CERN Document Server

Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; De Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Feld, L.; Fiedler, F.; Fierro, M.; Fleck, I.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I.; Layter, J.G.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Quadt, A.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; 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, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

2000-01-01

The helicity density matrix elements rho[00] of rho(770)+- and omega(782) mesons produced in Z decays have been measured using the OPAL detector at LEP. Over the measured meson energy range, the values are compatible with 1/3, corresponding to a statistical mix of helicity -1, 0 and +1 states. For the highest accessible scaled energy range 0.3 < x_E < 0.6, the measured rho[00] values of the rho(770)+- and the omega are 0.373 +- 0.052 and 0.142 +- 0.114, respectively. These results are compared to measurements of other vector mesons.

Meson exchange calculation of the p-barp→Lambda-barΛ reaction

International Nuclear Information System (INIS)

Tabakin, F.; Eisenstein, R.A.

1985-01-01

The process p-barp→Lambda-barΛ is studied using a one-boson t-channel strangeness exchange mechanism incorporating pseudoscalar, vector, and tensor mesons. Particular attention is paid to the spin degrees of freedom in the calculation. Initial and final state interactions, including the spin-orbit interaction and absorption, are taken into account using simple phenomenological models. The calculations are performed using density matrix ideas in the helicity basis, and the most important contributing amplitudes are identified. A reasonable fit to existing data can be obtained by allowing a smooth variation of the final state parameters with laboratory momentum. The effect of each of the exchanged mesons, and of the initial- and final-state baryon-baryon interactions on the cross sections and spin observables, is discussed. It is found that the tensor meson exchange plays an essential role even near threshold, which indicates the need for a detailed understanding of the short-range spin dynamics, perhaps as provided by future quark model studies

The effect of meson exchange on the forward cross section for d(γ,p)n

International Nuclear Information System (INIS)

Jaus, W.; Woolcock, W.S.

1981-01-01

We have investigated the effect of meson exchange on the theoretical calculation of the cross section for the photodisintegration of the deuteron in the forward direction, in the hope of reducing the present large discrepancy between theory and experiment. Two recent papers reporting a significant reduction in the discrepancy were found to have a sign error; when pseudoscalar πNN coupling is used the effect of one-pion exchange is to increase the discrepancy. We have calculated the one-pion and two-pion exchange effects on the E1 transitions using pseudovector πNN coupling and the resulting correction is small and in the right direction. Thus, assuming the reliability of both theory and experiment, our calculation provides a strong argument in favour of using PV rather than PS πNN coupling in calculating meson exchange effects in nuclear processes. We have found that the effect of the exchange of rho- and ω-mesons is very small. Meson exchange effects change the normalization of the deuteron wave function and cause a further small reduction in the calculated cross section. Since the corrections to the M1 transitions are expected to be very small, it seems unlikely that meson exchange effects can account for the discrepancy between theory and experiment. (orig.)

SU(2)-breaking effects for meson masses in lattice QCD

International Nuclear Information System (INIS)

Bramon, A.; Casulleras, J.

1989-01-01

The quenched approximation of lattice QCD for Wilson fermions is used to calculate isospin breaking effects in the pseudoscalar- and vector-meson nonets. Mass differences inside the K and K * isodoublets and mixing phenomena for π 0 -η and ρ-ω are found to agree with the experimental data. A new and specific method of analysis is proposed and successfully tested. (orig.)

Tetraquarks in the 1/N expansion and meson-meson resonances

Energy Technology Data Exchange (ETDEWEB)

Maiani, L. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); Polosa, A.D. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); CERN Theory Department, CH-1211 Geneva 23 (Switzerland); Riquer, V. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy)

2016-06-27

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Tetraquarks in the 1/N expansion and meson-meson resonances

International Nuclear Information System (INIS)

Maiani, L.; Polosa, A.D.; Riquer, V.

2016-01-01

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Production properties of K*(892) vector mesons and their spin alignment as measured in the NOMAD experiment

CERN Document Server

Chukanov, A; Popov, B; Astier, Pierre; Autiero, D; Baldisseri, Alberto; 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 L; Cardini, A; Cattaneo, P W; Cavasinni, V; Cervera-Villanueva, A; Challis, R; Collazuol, G; Conforto, G; Conta, C; Contalbrigo, M; Cousins, R; Daniels, D; Degaudenzi, H M; Del Prete, T; De Santo, A; Dignan, 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; Gómez-Cadenas, J J; Gosset, J; Gössling, C; Gouanère, M; Grant, A; Graziani, G; Guglielmi, A M; Hagner, C; Hernando, J; Hubbard, D; Hurst, P; Hyett, N; Iacopini, E; Joseph, C; Juget, F; Kent, N; Kirsanov, M; Klimov, O; Kokkonen, J; Kovzelev, A; Krasnoperov, A V; Lacaprara, S; Lachaud, C; Lakic, B; Lanza, A; La Rotonda, L; Laveder, M; Letessier-Selvon, A A; Lévy, J M; Linssen, Lucie; Ljubicic, A; Long, J; Lupi, A; Lyubushkin, V; Marchionni, A; Martelli, F; Méchain, X; Mendiburu, J P; Meyer, J P; Mezzetto, Mauro; Mishra, S R; Moorhead, G F; Nédélec, P; Nefedov, Yu; Nguyen-Mau, C; Orestano, D; Pastore, F; Peak, L S; Pennacchio, E; Pessard, H; Petti, R; Placci, A; Polesello, G; Pollmann, D; Polyarush, A Yu; Poulsen, C; Rebuffi, L; Renò, R; Rico, J; Riemann, P; Roda, C; Rubbia, André; 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; Stipcevic, M; Stolarczyk, T; Tareb-Reyes, M; Taylor, G N; Tereshchenko, V V; Toropin, A; Touchard, A M; Tovey, Stuart 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; Yabsley, B D; Zaccone, Henri; Zei, R; Zuber, K; Zuccon, P

2006-01-01

First measurements of K*(892) mesons production properties and their spin alignment in nu_mu charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For K*+ and K*- mesons produced in nu_mu CC interactions and decaying into K0 pi+/- we have found the following yields per event: (2.6 +/- 0.2 (stat.) +/- 0.2 (syst.))% and (1.6 +/- 0.1 (stat.) +/- 0.1 (syst.))% respectively, while for the K*+ and K*- mesons produced in nu NC interactions the corresponding yields per event are: (2.5 +/- 0.3 (stat.) +/- 0.3 (syst.))% and (1.0 +/- 0.3 (stat.) +/- 0.2 (syst.))%. The results obtained for the rho00 parameter, 0.40 +/- 0.06 (stat) +/- 0.03 (syst) and 0.28 +/- 0.07 (stat) +/- 0.03 (syst) for K*+ and K*- produced in nu_mu CC interactions, are compared to theoretical predictions tuned on LEP measurements in e+e- annihilation at the Z0 pole. For K*+ mesons produced in nu NC interactions the measured r...

Anomalous triple gauge couplings from $B$-meson and kaon observables

CERN Document Server

Bobeth, Christoph

2015-01-01

We consider the three CP-conserving dimension-6 operators that encode the leading new-physics effects in the triple gauge couplings. The contributions to the standard-model electromagnetic dipole and semi-leptonic vector and axial-vector interactions that arise from the insertions of these operators are calculated. We show that radiative and rare $B$-meson decays provide, under certain assumptions, constraints on two out of the three anomalous couplings that are competitive with the restrictions obtained from LEP II, Tevatron and LHC data. The constraints arising from the $Z \\to b \\bar b$ electroweak pseudo observables, $K \\to \\pi \

Topics in 2 + 1 and 3 + 1 dimensional physics

International Nuclear Information System (INIS)

Camperi, M.F.

1994-01-01

This thesis is concerned with the study of two different topics pertaining to two different dimensionalities in Field Theory. First, the issues Chern-Simons Gauge Field Theory in 2 + 1 dimensions, mainly as a field theoretic description of knots and links in three euclidean dimensions is addressed. The author provides both a non-perturbative and a perturbative approach, relating them in the large-N limit. A non-perturbative duality was found between the SU(N) k Chern-Simons theory and the SU(k) N one, providing a possible physical consequences of these constructions, notably the case of Fractional Statistics. Second, this thesis addresses the study of the so-called open-quotes vector modelclose quotes, written in the language of Chiral Perturbation Theory in the physical (3 + 1)-dimensional space time. This model was introduced as a possible way to study the physics of vector and pseudoscalar mesons and is based on the assumption that there is a limit of QCD where the vector mesons become massless. The author relates this model to the Hidden Symmetry Scheme, a model sharing the motivation with the previous one, but based on different assumptions. Considering only well established physical results as vector meson dominance, The thesis concludes that the vector model does not appear to be a good candidate for the effective description of vector mesons

Mesonic quasinormal modes of the Sakai-Sugimoto model at high temperature

International Nuclear Information System (INIS)

Evans, Nick; Threlfall, Ed

2008-01-01

We examine the mesonic thermal spectrum of the Sakai-Sugimoto model of holographic QCD by finding the quasinormal frequencies of the supergravity dual. If flavor is added using D8-D8 branes there exist embeddings where the D-brane world volume contains a black hole. For these embeddings (the high-temperature phase of the Sakai-Sugimoto model) we determine the quasinormal spectra of scalar and vector mesons arising from the world volume Dirac-Born-Infeld (DBI) action of the D-brane. We stress the importance of a coordinate change that makes the infalling quasinormal modes regular at the horizon allowing a simple numerical shooting technique. Finally we examine the effect of finite spatial momentum on quasinormal spectra

About absence of oscillations at CP violation and presence of interference between KS-, KL-meson states in the system of K0 mesons

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2014-01-01

Two approaches to the description of K 0 -, K 0 -bar-meson transitions into K 1 0 mesons at CP violation in weak interactions are considered. The first approach uses the standard theory of oscillations and the second approach supposes that (K S , K L ) states which arise at CP violation are normalized but not orthogonal state functions, then there arise interferences between these states but not oscillations. It is necessary to remark that the available experimental data are in good agreement with the second approach. So, we come to the conclusion that oscillations do not arise at CP violation in weak interactions in the system of K 0 mesons. Only interference between K S and K L states takes place here.

Magnetic monopole interactions: shell structure of meson and baryon states

International Nuclear Information System (INIS)

Akers, D.

1986-01-01

It is suggested that a low-mass magnetic monopole of Dirac charge g = (137/2)e may be interacting with a c-quark's magnetic dipole moment to produce Zeeman splitting of meson states. The mass M 0 = 2397 MeV of the monopole is in contrast to the 10 16 -GeV monopoles of grand unification theories (GUT). It is shown that shell structure of energy E/sub n/ = M 0 + 1/4nM 0 ... exists for meson states. The presence of symmetric meson states leads to the identification of the shell structure. The possible existence of the 2397-MeV magnetic monopole is shown to quantize quark masses in agreement with calculations of quantum chromodynamics (QCD). From the shell structure of meson states, the existence of two new mesons is predicted: eta(1814 +/- 50 MeV) with I/sup G/(J/sup PC/) = 0 + (0 -+ ) and eta/sub c/ (3907 +/- 100 MeV) with J/sup PC/ = 0 -+ . The presence of shell structure for baryon states is shown

Mesons in the Eguchi Kawai model

International Nuclear Information System (INIS)

Haan, O.

1985-09-01

Fermions in the fundamental representation of the SU(N) gauge group are incorporated into the Eguchi Kawai reduction scheme. The proof for the equivalence of reduced and extended theories is given. This equivalence can be used, to calculate chiral condensate and meson propagators from the fermion matrix of a partially reduced TEK model. (orig.)

Meson widths from string worldsheet instantons

International Nuclear Information System (INIS)

Faulkner, Thomas; Liu, Hong

2009-01-01

We show that open strings living on a D-brane which lies outside an AdS black hole can tunnel into the black hole through worldsheet instantons. These instantons have a simple interpretation in terms of thermal quarks in the dual Yang-Mills (YM) theory. As an application we calculate the width of a meson in a strongly coupled quark-gluon plasma which is described holographically as a massless mode on a D7 brane in AdS 5 xS 5 . While the width of the meson is zero to all orders in the 1/√(λ) expansion with λ the 't Hooft coupling, it receives non-perturbative contributions in 1/√(λ) from worldsheet instantons. We find that the width increases quadratically with momentum at large momentum and comment on potential phenomenological implications of this enhancement for heavy ion collisions. We also comment on how this non-perturbative effect has important consequences for the phase structure of the YM theory obtained in the classical gravity limit

A dependence of exclusive vector meson production in muon-nucleus scattering

International Nuclear Information System (INIS)

Fang, Guang Yin

1993-10-01

Preliminary results on the cross section ratios of exclusive ρ 0 and φ meson production off carbon, calcium, and lead to that off deuterium in deep-inelastic muon-nucleon scattering are reported. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam. The mean beam energy was 470 GeV. Significant increase in the cross section ratios is seen as the four-momentum squared of the virtual photon increases. The results support the idea of color transparency

Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

Institute of Scientific and Technical Information of China (English)

ZHOU Li-Juan; MA Wei-Xing

2002-01-01

Based on our low energy QCD Lagrangian description of strange meson photoproduction off the protonand the crossing symmetry, the strange meson radiative capture on the proton, K- + p →γ + A, is investigated in the[SUsF (6) O(3)]sym. SUc (3) quark model of baryon structure with the same input parameter, the only strong couplingconstant aM, as that in the strange meson photoproduction off the proton γ + p → K+ + A, a crossing channel of thecapture reaction. A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advancedand unified description of strange meson photoproduction and its associated radiative capture.

Probing the P -wave charmonium decays of Bc meson

Science.gov (United States)

Rui, Zhou

2018-02-01

Motivated by the large number of Bc meson decay modes observed recently by several detectors at the LHC, we present a detailed analysis of the Bc meson decaying to the P -wave charmonium states and a light pseudoscalar (P ) or vector (V ) meson within the framework of perturbative QCD factorization. The P -wave charmonium distribution amplitudes are extracted from the n =2 , l =1 Schrödinger states for a Coulomb potential, which can be taken as the universal nonperturbative objects to analyze the hard exclusive processes with P -wave charmonium production. It is found that these decays have large branching ratios of the order of 10-5˜10-2 , which seem to be in the reach of future experiments. We also provide predictions for the polarization fractions and relative phases of Bc→(χc 1,χc 2,hc)V decays. It is expected that the longitudinal polarization amplitudes dominate the branching ratios according to the quark helicity analysis, and the magnitudes and phases of parallel polarization amplitude are approximately equal to the perpendicular ones. The obtained results are compared with available experimental data, our previous studies, and numbers from other approaches.

Observation of two non-leading strangeness-one vector mesons

International Nuclear Information System (INIS)

Aston, D.; Dunwoodie, W.; Durkin, S.; Honma, A.; Hutchinson, D.; Johnson, W.B.; Kunz, P.F.; Lasinski, T.; Leith, D.W.G.S.; Levinson, L.; Meyer, W.T.; Ratcliff, B.N.; Shapiro, S.; Sinervo, P.K.; Suzuki, S.; Va'vra, J.; Williams, S.; Carnegie, R.K.; Estabrooks, P.G.; Hemingway, R.J.; McPherson, A.C.; Oakham, G.K.; McKee, R.

1984-01-01

We present evidence for the existence of two strange Jsup(P)=1 - mesons; one at 1410 MeV/c 2 coupling principally to Ksup(*)(892)π, and the other at 1790 MeV/c 2 coupling to Kπ, Ksup(*)π and rhoK. The data derive from a partial wave analysis of the anti K 0 π + π - system produced in the reaction K - p -> anti K 0 π + π - n at 11 GeV/c. The production mechanism and quark model assignment of each state are discussed. The state at 1410 MeV/c 2 is most naturally understood as the first radial excitation of the Ksup(*)(892), and the 1790 MeV/c 2 object can be interpreted as the triplet D wave partner to the 3 - Ksup(*)(1780). (orig.)

'Baldin autumn' and gauge fields

International Nuclear Information System (INIS)

Konopleva, N.P.

2008-01-01

The paper is the reminiscences of the participant of the gauge field theory beginning and the first 'Baldin Autumn' conference in 1969. This conference was named 'Vector Mesons and Electromagnetic Interactions'. At that time, just the processes with vector mesons participation contained some experimental indications of new universal interactions existence. Vector dominance was the experimental evidence of physical reasons of the gauge field theory. In the course of time the gauge field theory form, which was under discussion thirty seven years ago, became generally recognized and experimentally corroborated. It led to construction of the well-known Standard Model of elementary particle interactions

Vector theory of gravity: Universe without black holes and solution of dark energy problem

Science.gov (United States)

Svidzinsky, Anatoly A.

2017-12-01

We propose an alternative theory of gravity which assumes that background geometry of the Universe is fixed four dimensional Euclidean space and gravity is a vector field A k in this space which breaks the Euclidean symmetry. Direction of A k gives the time coordinate, while perpendicular directions are spatial coordinates. Vector gravitational field is coupled to matter universally and minimally through the equivalent metric f ik which is a functional of A k . We show that such assumptions yield a unique theory of gravity, it is free of black holes and, to the best of our knowledge, passes all available tests. For cosmology our theory predicts the same evolution of the Universe as general relativity with cosmological constant and zero spatial curvature. However, the present theory provides explanation of the dark energy as energy of longitudinal gravitational field induced by the Universe expansion and yields, with no free parameters, the value of {{{Ω }}}{{Λ }}=2/3≈ 0.67 which is consistent with the recent Planck result {{{Ω }}}{{Λ }}=0.686+/- 0.02. Such close agreement with cosmological data indicates that gravity has a vector, rather than tensor, origin. We demonstrate that gravitational wave signals measured by LIGO are compatible with vector gravity. They are produced by orbital inspiral of massive neutron stars which can exist in the present theory. We also quantize gravitational field and show that quantum vector gravity is equivalent to QED. Vector gravity can be tested by making more accurate measurement of the time delay of radar signal traveling near the Sun; by improving accuracy of the light deflection experiments; or by measuring propagation direction of gravitational waves relative to laser interferometer arms. Resolving the supermassive object at the center of our Galaxy with VLBA could provide another test of gravity and also shed light on the nature of dark matter.

A consistent meson-theoretic description of the NN-interaction

International Nuclear Information System (INIS)

Machleidt, R.

1985-01-01

In this paper, the meson-theory of the NN-interaction is performed consistently. All irreducible diagrams up to a total exchanged mass of about 1 GeV (i. e. up to the cutoff region) are taken into account. These diagrams contain in particular an explicit field theoretic model for the 2π-exchange taking into account virtual Δ-excitation and direct π π-interaction. This part of the model agrees quantitatively with results obtained from dispersion theory which in turn are based on the analysis of πN- and π π-scattering data. A detailed description of the lower partial wave phase-shifts of NN-scattering requires the introduction of irreducible diagrams containing also heavy boson exchange, in particular the combination of π and rho. In the framework of this consistent meson theory an accurate description of the NN-scattering data below 300 MeV laboratory energy as well as the deuteron data is achieved; the numerical results are superior to those of simplified boson exchange models

Analysis of Green's functions and stability problem in models of quantum field theory with solitons

International Nuclear Information System (INIS)

Raczka, R.; Roszkowski, L.

1983-10-01

A class of models of quantum field theory for a multiplet phi-vector=(phi 1 ,...,phisub(N)) of real scalar fields, possessing a particle-like classical solution phi-vector 0 , is considered. A new formula for generating functional for time-ordered Green's functions in terms of effective propagators is derived. The problem of classical and quantum stability is analyzed in detail. It is shown by partly non-perturbative analysis that in the considered models the excited states of mesons do exist and form the trajectories in the plane mass 2 -spin. These trajectories are linear or approximately linear like experimental trajectories. (author)

Non-perturbative RPA-method implemented in the Coulomb gauge QCD Hamiltonian: From quarks and gluons to baryons and mesons

Science.gov (United States)

Yepez-Martinez, Tochtli; Civitarese, Osvaldo; Hess, Peter O.

2018-02-01

Starting from an algebraic model based on the QCD-Hamiltonian and previously applied to study meson states, we have developed an extension of it in order to explore the structure of baryon states. In developing our approach we have adapted concepts taken from group theory and non-perturbative many-body methods to describe states built from effective quarks and anti-quarks degrees of freedom. As a Hamiltonian we have used the QCD Hamiltonian written in the Coulomb Gauge, and expressed it in terms of effective quark-antiquark, di-quarks and di-antiquark excitations. To gain some insights about the relevant interactions of quarks in hadronic states, the Hamiltonian was approximately diagonalized by mapping quark-antiquark pairs and di-quarks (di-antiquarks) onto phonon states. In dealing with the structure of the vacuum of the theory, color-scalar and color-vector states are introduced to account for ground-state correlations. While the use of a purely color-scalar ground state is an obvious choice, so that colorless hadrons contain at least three quarks, the presence of coupled color-vector pairs in the ground state allows for colorless excitations resulting from the action of color objects upon it.

Holographic corrections to meson scattering amplitudes

Energy Technology Data Exchange (ETDEWEB)

Armoni, Adi; Ireson, Edwin, E-mail: 746616@swansea.ac.uk

2017-06-15

We compute meson scattering amplitudes using the holographic duality between confining gauge theories and string theory, in order to consider holographic corrections to the Veneziano amplitude and associated higher-point functions. The generic nature of such computations is explained, thanks to the well-understood nature of confining string backgrounds, and two different examples of the calculation in given backgrounds are used to illustrate the details. The effect we discover, whilst only qualitative, is re-obtainable in many such examples, in four-point but also higher point amplitudes.

Observation of the weak time’s arrow in B mesons

CERN Multimedia

CERN. Geneva

2012-01-01

The mechanism of CP violation in weak interactions, as arising from the single physical phase in the CKM matrix, has been validated by more than a decade of intense experimental work probing CP violation, particularly with studies with B mesons. Since the Standard Model theory is CPT invariant, it predicts a “weak arrow of time” matching the large observed matter-antimatter asymmetry in B mesons. However, until recently there has been no direct observation of the expected, large time reversal (T) asymmetry. In this seminar we shall discuss how the BABAR experiment at SLAC has conducted a new data analysis where the decays of entangled neutral B mesons allow comparisons between the rates of four different transitions and their inverse, as a function of the time evolution of the B meson. The results lead to the first high significance, direct observation of T non-invariance through the exchange of initial and final states in transitions that can only be connected by a T symmetry transformation.

A transverse lattice QCD model for mesons

Energy Technology Data Exchange (ETDEWEB)

Patel, Apoorva D.; Ratabole, Raghunath

2004-03-01

QCD is analysed with two light-front continuum dimensions and two transverse lattice dimensions. In the limit of large number of colours and strong transverse gauge coupling, the contributions of light-front and transverse directions factorise in the dynamics, and the theory can be analytically solved in a closed form. An integral equation is obtained, describing the properties of mesons, which generalises the 't Hooft equation by including spin degrees of freedom. The meson spectrum, light-front wavefunctions and form factors can be obtained by solving this equation numerically. These results would be a good starting point to model QCD observables which only weakly depend on transverse directions, e.g. deep inelastic scattering structure functions.

Evidence for dynamic SU(5) symmetry breaking in meson mass multiplets

International Nuclear Information System (INIS)

Frikkee, E.

1994-07-01

It is shown that the mass differences and multiplet pattern for pseudoscalar and vector mesons correspond to a chain of dynamic symmetry reductions SU(n) contains SU(n-1)xU(1). In this symmetry-reduction model, the differences between the masses of the quark flavours are the result of intra-hadronic interactions. Quark confinement is explained as a consequence of the fact that this symmetry breaking chain only occurs in hadrons. The results of a quantitative analysis of mass splittings in meson multiplets indicate that SU(5) is probably the highest symmetry for hadron states. In the proposed dynamic symmetry breaking scheme with five quark flavours there is no one-to-one correspondence between lepton and quark generations. (orig.)

Meson Spectroscopy in the Light Quark Sector

Science.gov (United States)

De Vita, R.

2014-03-01

Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the qbar q configuration as tetraquarks (qqoverline{qq}), hybrids (qbar qg) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for qbar q states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e+e- annihilation, pbar p annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states. This intense effort is

Effective non-Coulombic power-law potential for the study of light and heavy mesons

International Nuclear Information System (INIS)

Barik, N.; Jena, S.N.

1982-01-01

From purely phenomenological considerations we have shown that it is possible to describe successfully the heavy meson spectra of cc-bar and bb-bar systems in the framework of an effective non-Coulombic power-law potential in the form V(r) = V 0 +ar/sup ν/ (with a,ν>0). The nonsingular short-distance behavior of this potential, which is in apparent contradiction with the predictions of quantum- chromodynamics, does not pose any problem in explaining the fine-hyperfine splitting, if we prescribe the spin dependence to be generated through this static confining potential in the form of an approximately equal admixture of scalar and vector parts with no contributions from the anomalous quark magnetic moments. This nonrelativistic formalsm, when extended to a unified study of the entire meson spectra including the ordinary light and the heavy mesons, gives a very good account of the meson masses, fine-hyperfine splittings, electromagnetic transition rates, and leptonic decay widths without reflecting any inadequacy in the short- and long-range behavior of this simple effective power-law potential

Propagation of gravitational waves in the generalized tensor-vector-scalar theory

International Nuclear Information System (INIS)

Sagi, Eva

2010-01-01

Efforts are underway to improve the design and sensitivity of gravitational wave detectors, with the hope that the next generation of these detectors will observe a gravitational wave signal. Such a signal will not only provide information on dynamics in the strong gravity regime that characterizes potential sources of gravitational waves, but will also serve as a decisive test for alternative theories of gravitation that are consistent with all other current experimental observations. We study the linearized theory of the tensor-vector-scalar theory of gravity with generalized vector action, an alternative theory of gravitation designed to explain the apparent deficit of visible matter in galaxies and clusters of galaxies without postulating yet-undetected dark matter. We find the polarization states and propagation speeds for gravitational waves in vacuum, and show that in addition to the usual transverse-traceless propagation modes, there are two more mixed longitudinal-transverse modes and two trace modes, of which at least one has longitudinal polarization. Additionally, the propagation speeds are different from the speed of light.

Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

Institute of Scientific and Technical Information of China (English)

ZHOULi－Juan; MAWei－Xing; 等

2002-01-01

Based on our low energy QCD Lagrangian description of strange meson photoproduction off the proton and the crossing symmetry,the strange meson radiative capture on the proton,K-+p→γ+A,is investigated in the [SU SF(6)×O(3)]sym,SUc(3) quark model of baryon structure with the same input parameter,the only strong coupling constant αM,as that in the strange meson photoproduction off the proton γ+p-→K+ Α，a crossing channel of the capture reaction,A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advanced and unified description of strange meson photoproduction and its associated radiative capture.

A review on the relativistic effective field theory with parameterized couplings for nuclear matter and neutron stars

Energy Technology Data Exchange (ETDEWEB)

Vasconcellos, C. A. Zen, E-mail: cesarzen@cesarzen.com [Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, 91501-970, Porto Alegre (Brazil); International Center for Relativistic Astrophysics Network (ICRANet), Piazza della Repubblica 10, 65122 Pescara (Italy)

2015-12-17

Nuclear science has developed many excellent theoretical models for many-body systems in the domain of the baryon-meson strong interaction for the nucleus and nuclear matter at low, medium and high densities. However, a full microscopic understanding of nuclear systems in the extreme density domain of compact stars is still lacking. The aim of this contribution is to shed some light on open questions facing the nuclear many-body problem at the very high density domain. Here we focus our attention on the conceptual issue of naturalness and its role in shaping the baryon-meson phase space dynamics in the description of the equation of state (EoS) of nuclear matter and neutrons stars. In particular, in order to stimulate possible new directions of research, we discuss relevant aspects of a recently developed relativistic effective theory for nuclear matter within Quantum Hadrodynamics (QHD) with genuine many-body forces and derivative natural parametric couplings. Among other topics we discuss in this work the connection of this theory with other known effective QHD models of the literature and its potentiality in describing a new physics for dense matter. The model with parameterized couplings exhausts the whole fundamental baryon octet (n, p, Σ{sup −}, Σ{sup 0}, Σ{sup +}, Λ, Ξ{sup −}, Ξ{sup 0}) and simulates n-order corrections to the minimal Yukawa baryon couplings by considering nonlinear self-couplings of meson fields and meson-meson interaction terms coupled to the baryon fields involving scalar-isoscalar (σ, σ∗), vector-isoscalar (ω, Φ), vector-isovector (ϱ) and scalar-isovector (δ) virtual sectors. Following recent experimental results, we consider in our calculations the extreme case where the Σ{sup −} experiences such a strong repulsion that its influence in the nuclear structure of a neutron star is excluded at all. A few examples of calculations of properties of neutron stars are shown and prospects for the future are discussed.

Photoproduction of Phi-mesons at small momentum transfer

International Nuclear Information System (INIS)

Hirschmann, H.

1975-09-01

The differential cross section of the γp → PHI, p → K + K - p reaction is determined for four-momentum transfer (0 - 0.23) GeV 2 and for photon energies (4.6 - 6.62) GeV with very small error. The differential cross section is independent of energy, the dependence on four-momentum transfer is described by an exponential function with a slope parameter (5.2 +- 0.4) GeV -2 . The total cross section of the PHI-meson as well as its differential cross section for elastic scattering at the proton comes out too small by a factor of 0.6 - 0.7 and 0.5 relative to predictions of a combined vector-dominance-quark model. The trajectories of the forward-going K-mesons are recorded in proportional and spark chambers, a threshold Cherenkov counter discriminates against fast pions and electrons, the principle of track reconstruction out of spark coordinates are explained in detail. (BJ) [de

Cosmological Solutions of Tensor–Vector Theories of Gravity by ...

Indian Academy of Sciences (India)

We consider tensor–vector theories by varying the space-time–matter coupling constant (varying Einstein velocity) in a spatially flat FRW universe.We examine the dynamics of this model by dynamical system method assuming a CDM background and we find some exact solutions by considering the character of critical ...

Radiative decay of mesons in an independent-quark potential model

International Nuclear Information System (INIS)

Barik, N.; Dash, P.C.; Panda, A.R.

1992-01-01

We investigate in a potential model of independent quarks the M1 transitions among the low-lying vector (V) and pseudoscalar (P) mesons. We perform a ''static'' calculation of the partial decay widths of twelve possible M1 transitions such as V→Pγ and P→Vγ within the traditional picture of photon emission by a confined quark and/or antiquark. The model accounts well for the observed decay widths

Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

International Nuclear Information System (INIS)

Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

2007-01-01

We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

Black hole perturbations in vector-tensor theories: the odd-mode analysis

Science.gov (United States)

Kase, Ryotaro; Minamitsuji, Masato; Tsujikawa, Shinji; Zhang, Ying-li

2018-02-01

In generalized Proca theories with vector-field derivative couplings, a bunch of hairy black hole solutions have been derived on a static and spherically symmetric background. In this paper, we formulate the odd-parity black hole perturbations in generalized Proca theories by expanding the corresponding action up to second order and investigate whether or not black holes with vector hair suffer ghost or Laplacian instabilities. We show that the models with cubic couplings G3(X), where X=‑AμAμ/2 with a vector field Aμ, do not provide any additional stability condition as in General Relativity. On the other hand, the exact charged stealth Schwarzschild solution with a nonvanishing longitudinal vector component A1, which originates from the coupling to the Einstein tensor GμνAμ Aν equivalent to the quartic coupling G4(X) containing a linear function of X, is unstable in the vicinity of the event horizon. The same instability problem also persists for hairy black holes arising from general quartic power-law couplings G4(X) ⊃ β4 Xn with the nonvanishing A1, while the other branch with A1=0 can be consistent with conditions for the absence of ghost and Laplacian instabilities. We also discuss the case of other exact and numerical black hole solutions associated with intrinsic vector-field derivative couplings and show that there exists a wide range of parameter spaces in which the solutions suffer neither ghost nor Laplacian instabilities against odd-parity perturbations.

Light-Meson Spectroscopy at Compass

Directory of Open Access Journals (Sweden)

Krinner Fabian

2017-01-01

The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV/c2. The flagship channel is the π−π+π− final state, for which Compass has recorded the currently world’s largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the a1(1420, with unusual properties. The findings are confirmed by the analysis of the π−π0π0 final state.

The time-dependent relativistic mean-field theory and the random phase approximation

International Nuclear Information System (INIS)

Ring, P.; Ma, Zhong-yu; Van Giai, Nguyen; Vretenar, D.; Wandelt, A.; Cao, Li-gang

2001-01-01

The Relativistic Random Phase Approximation (RRPA) is derived from the Time-Dependent Relativistic Mean-Field (TD RMF) theory in the limit of small amplitude oscillations. In the no-sea approximation of the RMF theory, the RRPA configuration space includes not only the usual particle-hole ph-states, but also αh-configurations, i.e. pairs formed from occupied states in the Fermi sea and empty negative-energy states in the Dirac sea. The contribution of the negative-energy states to the RRPA matrices is examined in a schematic model, and the large effect of Dirac-sea states on isoscalar strength distributions is illustrated for the giant monopole resonance in 116 Sn. It is shown that, because the matrix elements of the time-like component of the vector-meson fields which couple the αh-configurations with the ph-configurations are strongly reduced with respect to the corresponding matrix elements of the isoscalar scalar meson field, the inclusion of states with unperturbed energies more than 1.2 GeV below the Fermi energy has a pronounced effect on giant resonances with excitation energies in the MeV region. The influence of nuclear magnetism, i.e. the effect of the spatial components of the vector fields is examined, and the difference between the nonrelativistic and relativistic RPA predictions for the nuclear matter compression modulus is explained

Simulations for an experiment to probe the in-medium properties of photoproduced vector mesons

International Nuclear Information System (INIS)

Clarisse Tur

2003-01-01

The g7 experiment has been devised to measure the modifications of the vector meson properties, such as mass or width, inside nuclear medium, based on the ideas presented in the numerous papers published during the fifteen years that preceded its run. It consisted in sending a bremstrahlung photon beam on a target that contained elements with different densities, a liquid deuterium cell, and seven solid foils: carbon, iron, carbon, lead, carbon, titanium, carbon. The goal of the experiment is to examine the inclusive e + e - photoproduction in the incoherent region. The reaction of interest to g7 is γA → VA(prime) → e + e - A(prime) where V could be a ρ an ω or a φ meson. The goal of the present thesis was to present the simulation work done prior to the g7 run in the fall of 2002 at Jlab, essential for the choice of the ideal experimental setup and conditions, as well as the test run of June 2002. The simulations needed a particular attention, given the many experimental challenges that awaited the g7 team. First, one had to prove that the resolution of the CLAS detector was sufficient to properly locate the vertices of the events given the multi-segmented target, and the simulations proved that fact. They also provided a rough idea of the systematic errors that one had to expect. Using nuclei bigger than carbon was a first time for CLAS. Given the very small branching ratio for ρ → e + e - , a very intense beam had to be sent on the target containing high-Z material. Thus, a huge background, formed of low energy e + e - pairs, was expected around the target and the region I of the drift chambers and which one had to reduce in an efficient way. The simulations showed that using the mini torus with its current set to 75% of its maximum value would give a reduction of about a factor of 3 in the number of hits in the region I of the drift chambers, compared to the case with no mini torus in, which the test run confirmed. In addition, the branching ratio

Delocalized SYZ mirrors and confronting top-down SU(3)-structure holographic meson masses at finite g and Nc with P(article) D(ata) G(roup) values

International Nuclear Information System (INIS)

Yadav, Vikas; Sil, Karunava; Misra, Aalok

2017-01-01

Meson spectroscopy at finite gauge coupling - whereat any perturbative QCD computation would break down - and finite number of colors, from a top-down holographic string model, has thus far been entirely missing in the literature. This paper fills this gap. Using the delocalized type IIA SYZ mirror (with SU(3) structure) of the holographic type IIB dual of large-N thermal QCD of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) as constructed in Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at finite coupling and number of colors (N c = number of D5(D5)-branes wrapping a vanishing two-cycle in the top-down holographic construct of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) = O(1) in the IR in the MQGP limit of Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at the end of a Seiberg-duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of Sakai and Sugimoto (Prog Theor Phys 113:843. doi:10.1143/PTP.113.843 arXiv:hep-th/0412141, 2005) and Dasgupta et al. (JHEP 1507:122. doi:10.1007/JHEP07(2015)122 arXiv:1409.0559 [hep-th], 2015), and we obtain a closer match with the Particle Data Group (PDG) results of Olive et al. (Particle Data Group) (Chin Phys C 38:090001, 2014). Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons. The black-hole gravity dual (with a horizon radius smaller than the deconfinement scale) also provides the expected large-N suppressed decrease in vector meson mass with increase of temperature. (orig.)

Photoproduction of the eta prime meson in the effective Lagrangian approach

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyay, N.C.; Zhang, J.F. [Rensselaer Polytechnic Inst., Troy, NY (United States); Benmerrouche, M. [Univ. of Saskatchewan, Saskaton (Canada)

1994-04-01

In the framework of the effective Lagrangian approach, the authors study the {eta}{prime} photoproduction off protons, of great interest at CEBAF I and II. They calculate the contributions from the leading nucleon Born terms, vector meson exchanges, and estimate the resonance contributions, using the transition amplitudes from the recent quark model estimates by Capstick and Roberts. They discuss implications for the CEBAF experiments.

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP

International Nuclear Information System (INIS)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D 0 → K - π + , D + → K - π + π+ and D * +→ D 0 π + followed by D 0 → K - π + . Using also 1993 data and the channel D 0 → K - π + π + π - , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs

Temperature-dependent cross sections for meson-meson nonresonant reactions in hadronic matter

International Nuclear Information System (INIS)

Zhang Yiping; Xu Xiaoming; Ge Huijun

2010-01-01

We present a potential of which the short-distance part is given by one gluon exchange plus perturbative one- and two-loop corrections and of which the large-distance part exhibits a temperature-dependent constant value. The Schroedinger equation with this temperature-dependent potential yields a temperature dependence of the mesonic quark-antiquark relative-motion wave function and of meson masses. The temperature dependence of the potential, the wave function and the meson masses brings about temperature dependence of cross sections for the nonresonant reactions ππ→ρρ for I=2, KK→K*K* for I=1, KK*→K*K* for I=1, πK→ρK* for I=3/2, πK*→ρK* for I=3/2, ρK→ρK* for I=3/2 and πK*→ρK for I=3/2. As the temperature increases, the rise or fall of peak cross sections is determined by the increased radii of initial mesons, the loosened bound states of final mesons, and the total-mass difference of the initial and final mesons. The temperature-dependent cross sections and meson masses are parametrized.

Introduction to soft-collinear effective theory

CERN Document Server

Becher, Thomas; Ferroglia, Andrea

2015-01-01

Among resummation techniques for perturbative QCD in the context of collider and flavor physics, soft-collinear effective theory (SCET) has emerged as both a powerful and versatile tool, having been applied to a large variety of processes, from B-meson decays to jet production at the LHC.  This book provides a concise, pedagogical introduction to this technique. It discusses the expansion of Feynman diagrams around the high-energy limit, followed by the explicit construction of the effective Lagrangian - first for a scalar theory, then for QCD. The underlying concepts are illustrated with the quark vector form factor at large momentum transfer, and the formalism is applied to compute soft-gluon resummation and to perform transverse-momentum resummation for the Drell-Yan process utilizing renormalization group evolution in SCET. Finally, the infrared structure of n-point gauge-theory amplitudes is analyzed by relating them to effective-theory operators. This text is suitable for graduate students and non-spe...

ω→π0γ* and ϕ→π0γ* transition form factors in dispersion theory

Science.gov (United States)

Schneider, Sebastian P.; Kubis, Bastian; Niecknig, Franz

2012-09-01

We calculate the ω→π0γ* and ϕ→π0γ* electromagnetic transition form factors based on dispersion theory, relying solely on a previous dispersive analysis of the corresponding three-pion decays and the pion vector form factor. We compare our findings to recent measurements of the ω→π0μ+μ- decay spectrum by the NA60 collaboration, and strongly encourage experimental investigation of the Okubo-Zweig-Iizuka forbidden ϕ→π0ℓ+ℓ- decays in order to understand the strong deviations from vector-meson dominance found in these transition form factors.

Dynamical mechanism of symmetry breaking and particle mass generation in gauge field theories

International Nuclear Information System (INIS)

Miranskij, V.A.; Fomin, P.I.

1985-01-01

The dynamics of the spotaneous symmetry breaking and the particle mass generation in gauge theories with no fundamental scalar fields is considered. The emphasis is on the consideration of the symmetry breaking mechanism connected with the dynamics of the supercritical Coulomb-like forces caused by the gauge boson exchange between fermions. This mechanism is applied to different gauge theories, in particular, to the description of the spontaneous chira symmetry breaking in quantum chromodynamics. The mass relations for pseudoscalar meson nonet are obtained and it is shown that this mechanism resuls in the dynamical realisation of the hypothesis of the partial conservation of the axial-vector currents. The qualitative description of scalar mesons is given. The nature of the ultraviolet divergencies in quantum electrodynamics (QED) is investigated from the viewpoint of the dynamics of the fermion mass generation. The mechanism of the appearance of the additional (in comparison with perturbation theory) ultraviolet divergencies in QED with large bare coupling constant is indicated. The physical phenomenon underlying this mechanism is identified as the field theory analogue of the quantum mechanical ''fall into the centre'' (collapse) phenomenon. The similr phenomenon is shown to take place in some two-dimensional quantum field models. The dynamics of the bifermion condensates formation in tumblin gauge theories is briefly discussed

Analytic structure of ρ meson propagator at finite temperature

International Nuclear Information System (INIS)

Ghosh, Sabyasachi; Sarkar, Sourav; Mallik, S.

2010-01-01

We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the πω loop, that was ignored so far in the literature. (orig.)

Decay constants and radiative decays of heavy mesons in light-front quark model

International Nuclear Information System (INIS)

Choi, Ho-Meoyng

2007-01-01

We investigate the magnetic dipole decays V→Pγ of various heavy-flavored mesons such as (D,D*,D s ,D s *,η c ,J/ψ) and (B,B*,B s ,B s *,η b ,Υ) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F VP (q 2 ) for V→Pγ* decays are obtained in the q + =0 frame and then analytically continued to the timelike region by changing q perpendicular to iq perpendicular in the form factors. The coupling constant g VPγ for real photon case is then obtained in the limit as q 2 →0, i.e. g VPγ =F VP (q 2 =0). The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations

Elastic Photoproduction of $J/\\psi$ and $\\Upsilon$ Mesons 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.; 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.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; 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.; Ghazarian, S.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Hauschildt, T.; 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.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstrom, M.; List, B.; 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, T.; 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.; 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.I.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; 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.; 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.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

2000-01-01

Cross sections for elastic photoproduction of J/Psi and Upsilon mesons are presented. For J/Psi mesons the dependence on the photon-proton centre-of-mass energy W_gammap is analysed in an extended range with respect to previous measurements of 26<=W_gammap<= 285 GeV. The measured energy dependence is parameterized as sigma_gammap proportional W_gammap^delta with delta=0.83+-0.07. The differential cross section dsigma/dt for J/Psi mesons is derived, its dependence on W_gammap and on t is analysed and the effective trajectory (in terms of Regge theory) is determined to be alpha(t)=(1.27+-0.05)+(0.08+-0.17)*t/GeV^2. Models based on perturbative QCD and on pomeron exchange are compared to the data.

Can strong correlations be experimentally revealed for Ҡ -mesons?

Directory of Open Access Journals (Sweden)

Hiesmayr Beatrix C.

2014-01-01

Full Text Available In 1964 the physicists John St. Bell working at CERN took the 1935-idea of Einstein-Podolsky-Rosen seriously and found that all theories based on local realism have to satisfy a certain inequality, nowadays dubbed Bell’s inequality. Experiments with ordinary matter systems or light show violations of Bell’s inequality favouring the quantum theory though a loophole free experiment has not yet been performed. This contribution presents an experimentally feasible Bell inequality for systems at higher energy scales, i.e. entangled neutral Ҡ -meson pairs that are typically produced in Φ -mesons decays or proton-antiproton annihilation processes. Strong requirements have to be overcome in order to achieve a conclusive tests, such a proposal was recently published. Surprisingly, this new Bell inequality reveals new features for weakly decaying particles, in particular, a strong sensitivity to the combined charge-conjugation-parity (CP symmetry. Here-with, a puzzling relation between a symmetry breaking for mesons and Bell’s inequality—which is a necessary and sufficient condition for the security of quantum cryptography protocols— is established. This becomes the more important since CP symmetry is related to the cosmological question why the antimatter disappeared after the Big Bang.

Meson and isobar degrees of freedom in nuclear forces

International Nuclear Information System (INIS)

Vinh Mau, R.

1983-10-01

The current status of the low energy theory of the NN and NantiN interactions is reviewed, with special attention given to the role of the meson and isobar degrees of freedom. Phenomenology and fits to recent data are also described

Light vector meson production in pp collisions at sqrt(s) = 7 TeV

DEFF Research Database (Denmark)

Collaboration, ALICE; Abelev, B.; Abrahantes Quintana, A.

2012-01-01

The ALICE experiment has measured low-mass dimuon production in pp collisions at \\sqrt{s} = 7 TeV in the dimuon rapidity region 2.5y\\eta^{}, \\phi) into muons and semi-leptonic decays of charmed mesons. The measured production cross sections for \\omega and \\phi are \\sigma_\\omega (1p_t5 GeV/c,2.5y4...

Topics in the generalized vector dominance model

International Nuclear Information System (INIS)

Chavin, S.

1976-01-01

Two topics are covered in the generalized vector dominance model. In the first topic a model is constructed for dilepton production in hadron-hadron interactions based on the idea of generalized vector-dominance. It is argued that in the high mass region the generalized vector-dominance model and the Drell-Yan parton model are alternative descriptions of the same underlying physics. In the low mass regions the models differ; the vector-dominance approach predicts a greater production of dileptons. It is found that the high mass vector mesons which are the hallmark of the generalized vector-dominance model make little contribution to the large yield of leptons observed in the transverse-momentum range 1 less than p/sub perpendicular/ less than 6 GeV. The recently measured hadronic parameters lead one to believe that detailed fits to the data are possible under the model. The possibility was expected, and illustrated with a simple model the extreme sensitivity of the large-p/sub perpendicular/ lepton yield to the large-transverse-momentum tail of vector-meson production. The second topic is an attempt to explain the mysterious phenomenon of photon shadowing in nuclei utilizing the contribution of the longitudinally polarized photon. It is argued that if the scalar photon anti-shadows, it could compensate for the transverse photon, which is presumed to shadow. It is found in a very simple model that the scalar photon could indeed anti-shadow. The principal feature of the model is a cancellation of amplitudes. The scheme is consistent with scalar photon-nucleon data as well. The idea is tested with two simple GVDM models and finds that the anti-shadowing contribution of the scalar photon is not sufficient to compensate for the contribution of the transverse photon. It is found doubtful that the scalar photon makes a significant contribution to the total photon-nuclear cross section

Observability of B0 - B vector0 mixing in the e+e- → BB vector X reaction at √s approx. = 15 - 30 GeV

International Nuclear Information System (INIS)

Fridman, A.; Schwarz, A.

1985-01-01

The possibility of observing mixing in the B 0 B vector B 0 system has been rather widely discussed. In particular theoretical estimates have been made for the case of B 0 B vector 0 production in the e + e - → upsilon (4S) → B 0 B vector 0 reaction. Mixing in this specific channel is expected to appear as a small effect and might thus be hardly measurable. Here the authors will therefore consider the e + e - → BB vector X reaction (X meaning anything well above the BB vector threshold where any combination of BB vector mesons (B/sub u/B vector/sub u/, B/sub u/B vector/sub d/, B/sub u/B vector/sub s/, etc.) can be produced. This reaction might be advantageous as mixing is expected to be almost complete for the B/sub s/ mesons. In this respect the study of mixing effects in the e + e - → BB vector X reaction is complementary to that in the e + e - → upsilon (4S) → B/sub d/ 0 B vector /sub e/ 0 process. In Section B.2 the authors recall briefly the parameters used to describe the BB vector mixing and in Section B.3 they give estimates for the mixing effects which could be observed in the e + e - → BB vector X reaction as well as in the upsilon (4S) decays. The authors have also evaluated the influence of a non-spectator component in the B-decay on the observability of the mixing phenomenon. Finally, in Section B.4 they give estimates for the number of signal and background events which could be observed in an e + e - experiment with an accumulated luminosity of 1000 pb -1 . 33 references, 4 figures

Locally extracting scalar, vector and tensor modes in cosmological perturbation theory

International Nuclear Information System (INIS)

Clarkson, Chris; Osano, Bob

2011-01-01

Cosmological perturbation theory relies on the decomposition of perturbations into so-called scalar, vector and tensor modes. This decomposition is non-local and depends on unknowable boundary conditions. The non-locality is particularly important at second and higher order because perturbative modes are sourced by products of lower order modes, which must be integrated over all space in order to isolate each mode. However, given a trace-free rank-2 tensor, a locally defined scalar mode may be trivially derived by taking two divergences, which knocks out the vector and tensor degrees of freedom. A similar local differential operation will return a pure vector mode. This means that scalar and vector degrees of freedom have local descriptions. The corresponding local extraction of the tensor mode is unknown however. We give it here. The operators we define are useful for defining gauge-invariant quantities at second order. We perform much of our analysis using an index-free 'vector-calculus' approach which makes manipulating tensor equations considerably simpler. (papers)

Heavy-light mesons in lattice HQET and QCD

International Nuclear Information System (INIS)

Guazzini, D.

2007-12-01

We present a study of a combination of HQET and relativistic QCD to extract the b-quark mass and the B s -meson decay constant from lattice quenched simulations. We start from a small volume, where one can directly simulate the b-quark, and compute the connection to a large volume, where finite size effects are negligible, through a finite size technique. The latter consists of steps extrapolated to the continuum limit, where the b-region is reached through interpolations guided by the effective theory. With the lattice spacing given in terms of the Sommer's scale r 0 and the experimental B s and K masses, we get the final results for the renormalization group invariant mass M b =6.88(10) GeV, translating into anti m b (anti m b )=4.42(6) GeV in the MS scheme, and f B s =191(6) MeV for the decay constant. A renormalization condition for the chromo-magnetic operator, responsible, at leading order in the heavy quark mass expansion of HQET, for the mass splitting between the pseudoscalar and the vector channel in mesonic heavy-light bound states, is provided in terms of lattice correlations functions which well suits a non-perturbative computation involving a large range of renormalization scales and no valence quarks. The two-loop expression of the corresponding anomalous dimension in the Schroedinger functional (SF) scheme is computed starting from results in the literature; it requires a one-loop calculation in the SF scheme with a non-vanishing background field. The cutoff effects affecting the scale evolution of the renormalization factors are studied at one-loop order, and confirmed by non-perturbative quenched computations to be negligible for the numerical precision achievable at present. (orig.)

Heavy-light mesons in lattice HQET and QCD

Energy Technology Data Exchange (ETDEWEB)

Guazzini, D.

2007-12-15

We present a study of a combination of HQET and relativistic QCD to extract the b-quark mass and the B{sub s}-meson decay constant from lattice quenched simulations. We start from a small volume, where one can directly simulate the b-quark, and compute the connection to a large volume, where finite size effects are negligible, through a finite size technique. The latter consists of steps extrapolated to the continuum limit, where the b-region is reached through interpolations guided by the effective theory. With the lattice spacing given in terms of the Sommer's scale r{sub 0} and the experimental B{sub s} and K masses, we get the final results for the renormalization group invariant mass M{sub b}=6.88(10) GeV, translating into anti m{sub b}(anti m{sub b})=4.42(6) GeV in the MS scheme, and f{sub B{sub s}}=191(6) MeV for the decay constant. A renormalization condition for the chromo-magnetic operator, responsible, at leading order in the heavy quark mass expansion of HQET, for the mass splitting between the pseudoscalar and the vector channel in mesonic heavy-light bound states, is provided in terms of lattice correlations functions which well suits a non-perturbative computation involving a large range of renormalization scales and no valence quarks. The two-loop expression of the corresponding anomalous dimension in the Schroedinger functional (SF) scheme is computed starting from results in the literature; it requires a one-loop calculation in the SF scheme with a non-vanishing background field. The cutoff effects affecting the scale evolution of the renormalization factors are studied at one-loop order, and confirmed by non-perturbative quenched computations to be negligible for the numerical precision achievable at present. (orig.)

Phenomenology of pseudotensor mesons and the pseudotensor glueball

Energy Technology Data Exchange (ETDEWEB)

Koenigstein, Adrian [Johann Wolfgang Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Giacosa, Francesco [Jan Kochanowski University, Institute of Physics, Kielce (Poland); Johann Wolfgang Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany)

2016-12-15

We study the decays of the pseudotensor mesons (π{sub 2}(1670), K{sub 2}(1770), η{sub 2}(1645), η{sub 2}(1870)) interpreted as the ground-state nonet of 1{sup 1}D{sub 2} anti qq states using interaction Lagrangians which couple them to pseudoscalar, vector, and tensor mesons. While the decays of π{sub 2}(1670) and K{sub 2}(1770) can be well described, the decays of the isoscalar states η{sub 2}(1645) and η{sub 2}(1870) can be brought in agreement with the present experimental data only if the mixing angle between nonstrange and strange states is surprisingly large (about -42 {sup circle}, similar to the mixing in the pseudoscalar sector, in which the chiral anomaly is active). Such a large mixing angle is however at odd with all other conventional quark-antiquark nonets: if confirmed, a deeper study of its origin will be needed in the future. Moreover, the anti qq assignment of pseudotensor states predicts that the ratio [η{sub 2}(1870) → a{sub 2}(1320) π]/[η{sub 2}(1870) → f{sub 2}(1270) η] is about 23.5. This value is in agreement with Barberis et al., (20.4 ± 6.6), but disagrees with the recent reanalysis of Anisovich et al., (1.7 ± 0.4). Future experimental studies are necessary to understand this puzzle. If Anisovich's value is confirmed, a simple nonet of pseudoscalar mesons cannot be able to describe data (different assignments and/or additional states, such as an hybrid state, will be needed). In the end, we also evaluate the decays of a pseudoscalar glueball into the aforementioned conventional anti qq states: a sizable decay into K{sub 2}{sup *}(1430) K and a{sub 2}(1230) π together with a vanishing decay into pseudoscalar-vector pairs (such as ρ(770) π and K*(892) K) are expected. This information can be helpful in future studies of glueballs at the ongoing BESIII and at the future PANDA experiments. (orig.)

Delocalized SYZ mirrors and confronting top-down SU(3)-structure holographic meson masses at finite g and N_c with P(article) D(ata) G(roup) values

Science.gov (United States)

Yadav, Vikas; Misra, Aalok; Sil, Karunava

2017-10-01

Meson spectroscopy at finite gauge coupling - whereat any perturbative QCD computation would break down - and finite number of colors, from a top-down holographic string model, has thus far been entirely missing in the literature. This paper fills this gap. Using the delocalized type IIA SYZ mirror (with SU(3) structure) of the holographic type IIB dual of large- N thermal QCD of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) as constructed in Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at finite coupling and number of colors (N_c = number of D5(\\overline{D5})-branes wrapping a vanishing two-cycle in the top-down holographic construct of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) = O(1) in the IR in the MQGP limit of Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at the end of a Seiberg-duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of Sakai and Sugimoto (Prog Theor Phys 113:843. doi: 10.1143/PTP.113.843 arXiv:hep-th/0412141, 2005) and Dasgupta et al. (JHEP 1507:122. doi: 10.1007/JHEP07(2015)122 arXiv:1409.0559 [hep-th], 2015), and we obtain a closer match with the Particle Data Group (PDG) results of Olive et al. (Particle Data Group) (Chin Phys C 38:090001, 2014). Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons. The black-hole gravity dual (with a horizon radius smaller than the deconfinement scale) also provides the expected large- N suppressed decrease in vector meson mass with increase of temperature.

MesonNet Workshop on Meson Transition Form Factors

CERN Document Server

Eidelman, S; Hanhart, C; Kubis, B; Kupsc, A; Leupold, S; Moskal, P; Schadmand, S

2012-01-01

The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.

Exclusive ρ.sup.0./sup. meson photoproduction with a leading neutron at HERA

Czech Academy of Sciences Publication Activity Database

Andreev, V.; Baghdasaryan, A.; Begzsuren, K.; Cvach, Jaroslav; Hladký, Jan; Reimer, Petr

2016-01-01

Roč. 76, č. 1 (2016), 1-21, č. článku 41. ISSN 1434-6044 R&D Projects: GA MŠk LG14033 Institutional support: RVO:68378271 Keywords : deep-inelastic scattering * vector meson production * pion exchange model * elastic photoproduction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.331, year: 2016

Algebra of Complex Vectors and Applications in Electromagnetic Theory and Quantum Mechanics

Directory of Open Access Journals (Sweden)

Kundeti Muralidhar

2015-08-01

Full Text Available A complex vector is a sum of a vector and a bivector and forms a natural extension of a vector. The complex vectors have certain special geometric properties and considered as algebraic entities. These represent rotations along with specified orientation and direction in space. It has been shown that the association of complex vector with its conjugate generates complex vector space and the corresponding basis elements defined from the complex vector and its conjugate form a closed complex four dimensional linear space. The complexification process in complex vector space allows the generation of higher n-dimensional geometric algebra from (n — 1-dimensional algebra by considering the unit pseudoscalar identification with square root of minus one. The spacetime algebra can be generated from the geometric algebra by considering a vector equal to square root of plus one. The applications of complex vector algebra are discussed mainly in the electromagnetic theory and in the dynamics of an elementary particle with extended structure. Complex vector formalism simplifies the expressions and elucidates geometrical understanding of the basic concepts. The analysis shows that the existence of spin transforms a classical oscillator into a quantum oscillator. In conclusion the classical mechanics combined with zeropoint field leads to quantum mechanics.

Meson and baryon production in K/sup +/ and. pi. /sup +/ beam jets and quark-diquark cascade model

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, Kisei [Kagoshima Univ. (Japan). Faculty of Education; Noda, Hujio; Tashiro, Tsutomu

1982-11-01

A quark-diquark cascade model which includes flavor dependence and resonance effect is studied. The inclusive distributions of vector and pseudoscalar mesons and octet baryons and antibaryons in K/sup +/ and ..pi../sup +/ beam jets are analyzed. The contribution of decuplet baryons to the octet baryon spectra is very important in meson beam jet. The effects of the asymmetric u- and anti s-quark distributions in K/sup +/ and the SU(6)-symmetry breaking for the produced octet baryon are discussed in connection with the ..pi../sup +//K/sup +/ beam ratio and other data.

A search for light gluinos, and, Heavy quark effective field theory and B-physics with applications to the collider detector at Fermilab

International Nuclear Information System (INIS)

Cakir, M.B.

1993-01-01

In the first part of this dissertation a search for light gluinos in the 0(1 GeV) region - especially in radiative decays of vector quarkonia - is presented. It is shown that light gluinos have not been excluded by experiments to date. In fact some evidence contrary to that fact is presented. In the second part the recent Heavy Quark Effective Field Theory methods are used in calculating rare decays of vector and pseudoscalar mesons of b-quarks. Applications to the Collider Detector at Fermilab environment are discussed

Structure of the (0+,1+) mesons Bs0 and Bs1, and the strong coupling constant gBs0BK and gBs1B*K

International Nuclear Information System (INIS)

Wang, Z. G.

2008-01-01

In this article, we take the point of view that the bottomed (0 + ,1 + ) mesons B s0 and B s1 are the conventional bs meson and calculate the strong coupling constants g B s0 BK and g B s1 B*K with the light-cone QCD sum rules. The numerical values of strong coupling constants g B s1 B*K and g B s0 BK are very large and support the hadronic dressing mechanism. Just like the scalar mesons f 0 (980), a 0 (980), D s0 and axial-vector meson D s1 , the (0 + ,1 + ) bottomed mesons B s0 and B s1 may have small bs kernels of the typical bs meson size. The strong couplings to the hadronic channels (or the virtual mesons loops) may result in smaller masses than the conventional bs mesons in the potential quark models and enrich the pure bs states with other components.

A non-linear field theory

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

A unified field theory of mesons and their particle sources is proposed and considered in its classical aspects. The theory has static solutions of a singular nature, but finite energy, characterized by spin directions; the number of such entities is a rigorously conserved constant of motion; they interact with an external meson field through a derivative-type coupling with the spins, akin to the formalism of strong-coupling meson theory. There is a conserved current identifiable with isobaric spin, and another that may be related to hypercharge. The postulates include one constant of the dimensions of length, and another that is conjecture necessarily to have the value (h/2π)c, or perhaps 1/2(h/2π)c, in the quantized theory. (author). 5 refs

ψ(2S) Hadronic Decays to Vector-Tensor Final States

International Nuclear Information System (INIS)

Bai, J.Z.; Bian, J.G.; Chai, Z.W.; Chen, G.P.; Chen, J.C.; Chen, Y.; Chen, Y.B.; Chen, Y.Q.; Cheng, B.S.; Cui, X.Z.; Ding, H.L.; Ding, L.Y.; Dong, L.Y.; Du, Z.Z.; Feng, S.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gu, J.H.; Gu, S.D.; Gu, W.X.; Gu, Y.F.; Guo, Y.N.; Han, S.W.; Han, Y.; He, J.; He, J.T.; Hu, G.Y.; Hu, H.M.; Hu, J.L.; Hu, Q.H.; Hu, T.; Hu, X.Q.; Huang, J.D.; Huang, Y.Z.; Jiang, C.H.; Jin, Y.; Ke, Z.J.; Lai, Y.F.; Lang, P.F.; Li, C.G.; Li, D.; Li, H.B.; Li, J.; Li, P.Q.; Li, R.B.; Li, W.; Li, W.D.; Li, W.G.; Li, X.H.; Li, X.N.; Liu, H.M.; Liu, J.; Liu, J.H.; Liu, R.G.; Liu, Y.; Lu, F.; Lu, J.G.; Lu, J.Y.; Lu, L.C.; Luo, C.H.; Ma, A.M.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Meng, X.C.; Nie, J.; Qi, N.D.; Qi, X.R.; Qiu, J.F.; Qu, Y.H.; Que, Y.K.; Rong, G.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, H.; Shen, X.Y.; Sheng, H.Y.; Shi, H.Z.; Song, X.F.; Sun, F.; Sun, H.S.; Tang, S.Q.; Tong, G.L.; Wang, F.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, T.J.; Wang, Y.Y.; Wei, C.L.; Wu, Y.G.; Xi, D.M.; Xia, X.M.; Xie, P.P.; Xie, Y.; Xie, Y.H.; Xiong, W.J.; Xu, C.C.; Xu, G.F.; Xue, S.T.; Yan, J.; Yan, W.G.; Yang, C.M.; Yang, C.Y.; Yang, J.; Yang, X.F.; Ye, M.H.; Yi, K.; Yu, C.S.; Yu, C.X.; Yu, Z.Q.; Yu, Z.T.; Yuan, C.Z.; Yuan, Y.; Zhang, B.Y.; Zhang, C.C.; Zhang, D.H.; Zhang, D.; Zhang, H.L.; Zhang, J.; Zhang, J.L.; Zhang, J.W.; Zhang, L.S.; Zhang, Q.J.; Zhang, S.Q.; Zhang, Y.; Zhang, Y.Y.; Zhao, D.X.; Zhao, H.W.; Zhao, J.W.; Zhao, M.; Zhao, W.R.; Zhao, Z.G.; Zheng, J.P.; Zheng, L.S.; Zheng, Z.P.; Zhou, G.P.; Zhou, H.S.; Zhou, L.; Zhu, Q.M.; Zhu, Y.C.; Zhu, Y.S.; Zhuang, B.A.; Hitlin, D.G.; Kelsey, M.H.; Oyang, J.; Panetta, J.; Porter, F.; Weaver, M.; Chen, J.; Malchow, R.; Toki, W.; Yang, W.

1998-01-01

The decays of the ψ(2S) into vector plus tensor meson final states have been studied for the first time using the BES detector. We determine upper limits on branching fractions for ψ(2S) decays into ωf 2 , ρa 2 , K *0 K *0 2 +c.c. , and φf ' 2 (1525) that are, in each case, significantly smaller than the corresponding branching fractions for the J/ψ meson, scaled according to the expectations of perturbative QCD. copyright 1998 The American Physical Society

Equality of e+e- production amplitudes for scalar-vector and pseudoscalar-axial heavy meson-antimeson pairs

Science.gov (United States)

Voloshin, M. B.

2018-02-01

The production of heavy meson-antimeson pairs of the type S V and P A in e+e- annihilation is considered, with P and V being the ground-state JP=0- and JP=1- (anti)mesons from the (1 /2 )-doublet and S and A standing for the excited JP=0+ and JP=1+ (anti)mesons from the (1 /2 )+doublet. It is argued that the production amplitudes in these two channels should be equal up to a higher (than one) order in the heavy quark mass (ΛQCD/MQ ) expansion, A (e +e-→S V ¯ )=A (e+e-→A P ¯ ) , including both the S -wave and the D -wave amplitudes. Given that the S V and P A thresholds are extremely close, the production cross section in both channels should be the same to a high degree of accuracy. In practice, this behavior can be studied for the processes e+e-→Ds 0(2317 )D¯s *+c .c . and e+e-→Ds 1(2460 )D¯ s+c .c . in the charm sector and e+e-→Bs 0B¯s *+c .c . and e+e-→Bs 1B¯ s+c .c . in the B sector.

B meson decays to baryons in the diquark model

International Nuclear Information System (INIS)

Chang, C.H.V.; Hou, W.S.

2002-01-01

We study B meson decays to two charmless baryons in the diquark model, including strong and electroweak penguins as well as the tree operators. It is shown that penguin operators can enhance anti B→B s anti B considerably, but affect anti B→B 1 anti B 2 only slightly, where B (1,2) and B s are non-strange and strange baryons, respectively. The γ dependence of the decay rates due to tree-penguin interference is illustrated. In principle, some of the B s anti B modes could dominate over B 1 anti B 2 for γ>90 , but in general the effect is milder than their mesonic counterparts. This is because the O 6 operator can only produce vector but not scalar diquarks, while the opposite is true for O 1 and O 4 . Predictions from the diquark model are compared to those from the sum rule calculation. The decays anti B→B s anti B s and inclusive baryonic decays are also discussed. (orig.)

A chiral covariant approach to ρρ scattering

Energy Technology Data Exchange (ETDEWEB)

Guelmez, D. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Meissner, U.G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Institut fuer Kernphysik and Juelich Center for Hadron Physics, Institute for Advanced Simulation, Juelich (Germany); Oller, J.A. [Universidad de Murcia, Departamento de Fisica, Murcia (Spain)

2017-07-15

We analyze vector meson-vector meson scattering in a unitarized chiral theory based on a chiral covariant framework restricted to ρρ intermediate states. We show that a pole assigned to the scalar meson f{sub 0}(1370) can be dynamically generated from the ρρ interaction, while this is not the case for the tensor meson f{sub 2}(1270) as found in earlier work. We show that the generation of the tensor state is untenable due to the extreme non-relativistic kinematics used before. We further consider the effects arising from the coupling of channels with different orbital angular momenta which are also important. We suggest to use the formalism outlined here to obtain more reliable results for the dynamical generation of resonances in the vector-vector interaction. (orig.)

Background Killing vectors and conservation laws in Rosen's bimetric theories of gravitation

International Nuclear Information System (INIS)

Israelit, M.

1979-01-01

The problem of global energy, linear momentum, and angular momentum in Rosen's bimetric theories of gravitation is considered from the point of view of motions of the background space-time. It turns out that by means of background Killing vectors global mechanical integrals for matter and field can be defined in a correct manner. For the flat-background bimetric theory conditions are obtained which have been imposed on the algebraic structure of the matter tensor Tsub(μ)sup(ν) in order to get global mechanical conservation laws. For bimetric gravitation theories based on a cosmological (nonflat) background the set of Killing vectors is found. For these theories the obtained restrictions on the algebraic structure of Tsub(μ)sup(ν) lead to global generation laws (instead of conservation laws in the flat-background theory) for mechanical quantities. In particular cases the generation effect vanishes and then conservation laws exist. By means of the method developed in this paper, Rosen's homogeneous isotropic universe in the framework of the cosmological-background bimetric theory with k = 1 is considered. It turns out that such a universe does not generate globally, but will generate locally. The global energy of this universe is found to be zero. (author)

Associative birth of the J/PSI meson and photon in the polarizing ep and pp interactions

International Nuclear Information System (INIS)

Temiraliev, A.T.

2001-01-01

Appearance of so named 'spin crisis' acutely states the problem about role of gluons and sea quacks in nucleon spin structure function. For revealing of gluons contribution the joint birth of J/PSI meson and photon with opposite transverse impulse in polarizing electron-proton and proton-proton interactions have been studied. Calculation have been carried within the framework of the theory of quantum chromodynamics collisions. Charming meson decay into either electron-positron pair or meson pair gives experimental pure finite state. Measurement of the polarizing asymmetry of associative birth of J/PSI meson and photon in the result of both experiments (ep and pp) allow to determine gluons polarization unambiguously

Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy-light mesons

Energy Technology Data Exchange (ETDEWEB)

Lucha, Wolfgang [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); Melikhov, Dmitri [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); University of Vienna, Faculty of Physics, Vienna (Austria); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Rome (Italy)

2018-02-15

We discuss the leptonic decay constants of heavy-light mesons by means of Borel QCD sum rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all vacuum-condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective threshold. We study properties of the LD effective thresholds in the limits of large heavy-quark mass m{sub Q} and small light-quark mass m{sub q}. In the heavy-quark limit, we clarify the role played by the radiative corrections in the effective threshold for reproducing the pQCD expansion of the decay constants of pseudoscalar and vector mesons. We show that the dependence of the meson decay constants on m{sub q} arises predominantly (at the level of 70-80%) from the calculable m{sub q}-dependence of the perturbative spectral densities. Making use of the lattice QCD results for the decay constants of nonstrange and strange pseudoscalar and vector heavy mesons, we obtain solid predictions for the decay constants of heavy-light mesons as functions of m{sub q} in the range from a few to 100 MeV and evaluate the corresponding strong isospin-breaking effects: f{sub D{sup +}} - f{sub D{sup 0}} = (0.96 ± 0.09) MeV, f{sub D}{sup {sub *}{sub +}} - f{sub D}{sup {sub *}{sub 0}} = (1.18 ± 0.35) MeV, f{sub B{sup 0}} - f{sub B{sup +}} = (1.01 ± 0.10) MeV, f{sub B}{sup {sub *}{sub 0}} - f{sub B}{sup {sub *}{sub +}} = (0.89 ± 0.30) MeV. (orig.)

Density dependent hadron field theory

International Nuclear Information System (INIS)

Fuchs, C.; Lenske, H.; Wolter, H.H.

1995-01-01

A fully covariant approach to a density dependent hadron field theory is presented. The relation between in-medium NN interactions and field-theoretical meson-nucleon vertices is discussed. The medium dependence of nuclear interactions is described by a functional dependence of the meson-nucleon vertices on the baryon field operators. As a consequence, the Euler-Lagrange equations lead to baryon rearrangement self-energies which are not obtained when only a parametric dependence of the vertices on the density is assumed. It is shown that the approach is energy-momentum conserving and thermodynamically consistent. Solutions of the field equations are studied in the mean-field approximation. Descriptions of the medium dependence in terms of the baryon scalar and vector density are investigated. Applications to infinite nuclear matter and finite nuclei are discussed. Density dependent coupling constants obtained from Dirac-Brueckner calculations with the Bonn NN potentials are used. Results from Hartree calculations for energy spectra, binding energies, and charge density distributions of 16 O, 40,48 Ca, and 208 Pb are presented. Comparisons to data strongly support the importance of rearrangement in a relativistic density dependent field theory. Most striking is the simultaneous improvement of charge radii, charge densities, and binding energies. The results indicate the appearance of a new ''Coester line'' in the nuclear matter equation of state

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)

Nucleon-nucleon scattering and different meson exchanges

International Nuclear Information System (INIS)

Osman, A.

1985-10-01

The iterative and noniterative diagrams with different meson exchange are investigated. The α, πβ and πγ meson exchange, (where α=π, rho, σ, ω, eta and delta; β=π, rho, σ and ω; γ=π and rho), are considered. These diagrams are taken to involve the nucleon-nucleon, the nucleon-isobar and the isobar-isobar intermediate states. The diagrams are calculated in momentum space following the noncovariant perturbation theory. The role of each of these diagrams is examined by calculating its contribution to the nucleon-nucleon interaction. The potential model is taken to include one-boson-exchange terms in addition to these diagrams. The nucleon-nucleon scattering phase shifts are described successfully showing the importance of tensor force. The contributions of the different parts are studied in the nucleon-nucleon scattering. (author)

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP; Etude de la fragmentation des quarks lourds en mesons charmes dans l`experience Delphi au LEP

Energy Technology Data Exchange (ETDEWEB)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D{sup 0}{yields} K{sup -} {pi}{sup +} , D{sup +}{yields} K{sup -} {pi}{sup +}{pi}+ and D{sup *}+{yields} D{sup 0}{pi}{sup +} followed by D{sup 0}{yields} K{sup -}{pi}{sup +} . Using also 1993 data and the channel D{sup 0}{yields} K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs.

A global fit to determine the pseudoscalar mixing angle and the gluonium content of the η' meson

International Nuclear Information System (INIS)

Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bertolucci, S.; Bloise, C.; Bossi, F.; Capon, G.; Capussela, T.; Ciambrone, P.; De Lucia, E.; De Simone, P.; Archilli, F.; Beltrame, P.; Bini, C.; De Santis, A.; De Zorzi, G.; Bocchetta, S.; Ceradini, F.; Branchini, P.

2009-01-01

We update the values of the η-η' mixing angle and of the η' gluonium content by fitting our measurement R φ = BR(φ → η'γ)/BR(φ → ηγ) together with several vector meson radiative decays to pseudoscalars (V → Pγ), pseudoscalar mesons radiative decays to vectors (P → Vγ) and the η' → γγ, π 0 → γγ widths. From the fit we extract a gluonium fraction of Z G 2 = 0.12±0.04, the pseudoscalar mixing angle ψ P = (40.4±0.6) 0 and the φ-ω mixing angle ψ V = (3.32±0.09) 0 . Z G 2 and ψ P are fairly consistent with those previously published. We also evaluate the impact on the η' gluonium content determination of future experimental improvements of the η' branching ratios and decay width.

Vector current scattering in two dimensional quantum chromodynamics

International Nuclear Information System (INIS)

Fleishon, N.L.

1979-04-01

The interaction of vector currents with hadrons is considered in a two dimensional SU(N) color gauge theory coupled to fermions in leading order in an N -1 expansion. After giving a detailed review of the model, various transition matrix elements of one and two vector currents between hadronic states were considered. A pattern is established whereby the low mass currents interact via meson dominance and the highly virtual currents interact via bare quark-current couplings. This pattern is especially evident in the hadronic contribution to inelastic Compton scattering, M/sub μν/ = ∫ dx e/sup iq.x/ , which is investigated in various kinematic limits. It is shown that in the dual Regge region of soft processes the currents interact as purely hadronic systems. Modification of dimensional counting rules is indicated by a study of a large angle scattering analog. In several hard inclusive nonlight cone processes, parton model ideas are confirmed. The impulse approximation is valid in a Bjorken--Paschos-like limit with very virtual currents. A Drell--Yan type annihilation mechanism is found in photoproduction of massive lepton pairs, leading to identification of a parton wave function for the current. 56 references

The (0+,1+) heavy meson multiplet in an extended NJL model

International Nuclear Information System (INIS)

Ebert, T.; Feldmann, T.; Friedrich, R.; Reinhardt, H.

1994-09-01

In this letter we reconsider the previously given description of heavy mesons with a bosonized extended NJL model that combines heavy quark and chiral symmetry. In that work the naive gradient expansion of the quark determinant was used, which satisfactorily works in the light sector but does not adequately describe the heavy (0 + , 1 + ) mesons. By investigating the exact momentum dependence of the quark loop we demonstrate that the naive gradient expansion in the heavy sector is not the right method to treat the unphysical q anti q-thresholds which would be absent in confining theories. We propose a modified gradient expansion which adequately extrapolates from the low-momentum region beyond threshold. This expansion gives a satisfactory description even of the (0 + , 1 + ) heavy mesons whose masses are significantly above threshold. (orig.)

High energy deeply virtual Compton scattering on a photon and related meson exclusive production

International Nuclear Information System (INIS)

Machado, Magno V. T.

2007-01-01

In this work we estimate the differential cross section for the high energy deeply virtual Compton scattering on a photon target, γ*γ→γγ, within the QCD dipole-dipole scattering formalism. For the phenomenology, a saturation model for the dipole-dipole cross section for two photon scattering is considered. Its robustness is supported by a good description of current accelerator data. In addition, we consider the related exclusive vector meson production processes, γ*γ→Vγ. This analysis is focused on the light ρ and φ meson production, which produces larger cross sections. The phenomenological results are compared with the theoretical calculation using the color-dipole Balitsky-Fadin-Kuraev-Lipatov approach

Linking Simple Economic Theory Models and the Cointegrated Vector AutoRegressive Model

DEFF Research Database (Denmark)

Møller, Niels Framroze

This paper attempts to clarify the connection between simple economic theory models and the approach of the Cointegrated Vector-Auto-Regressive model (CVAR). By considering (stylized) examples of simple static equilibrium models, it is illustrated in detail, how the theoretical model and its stru....... Further fundamental extensions and advances to more sophisticated theory models, such as those related to dynamics and expectations (in the structural relations) are left for future papers......This paper attempts to clarify the connection between simple economic theory models and the approach of the Cointegrated Vector-Auto-Regressive model (CVAR). By considering (stylized) examples of simple static equilibrium models, it is illustrated in detail, how the theoretical model and its......, it is demonstrated how other controversial hypotheses such as Rational Expectations can be formulated directly as restrictions on the CVAR-parameters. A simple example of a "Neoclassical synthetic" AS-AD model is also formulated. Finally, the partial- general equilibrium distinction is related to the CVAR as well...

Charmed meson production at LHCb

International Nuclear Information System (INIS)

Müller, Dominik

2016-01-01

Measurements of charm meson production are important tests for QCD predictions and LHCb is uniquely suited to perform these measurements in the forward region. This paper summarises recent charm meson production measurements performed by LHCb of J/ψ and open charm mesons and the associated production of ϒ and open charm mesons. The J/ψ and open charm meson measurements are performed with data recorded in Run 2 of the Large Hadron Collider. With proton-proton collisions at √s = 13 TeV, these open a new regime in which QCD predictions for charm meson production may be precisely tested. Furthermore, ratios of cross-sections at different centre-of-mass energies benefit of cancellation of both experimental and theoretical uncertainties, providing a new sensitive test of the QCD calculations. Measurements of ϒ and open charm meson associated production are performed using √s = 7 TeV and √s = 8 TeV data and constitute the first observation of this production channel.

Mass and scattering length inequalities in QCD and QCD-like theories

International Nuclear Information System (INIS)

Nussinov, S.; Pennsylvania Univ., Philadelphia; Sathiapalan, B.

1985-01-01

Some observations about mass scattering length inequalities in QCD-like theories are presented. It is shown that the Weingarten mass inequality can be used to argue that global vector symmetries are unbroken in such theories. For QCD, in the limit Nsub(c)->infinite, it is shown that Msub(baryon)>=1/2Nsub(c)Msub(meson), provided there are at least Nsub(c) degenerate flavors of quarks. It is argued that when there are not bound states in a scattering channel, the mass inequalities can be used to derive inequalities beteen scattering lengths. Some rigorous inequalities for two and higher point functions for operators bilinear in currents are derived, and used to extract inequalities between quartic coupling constants. (orig.)

On the cosmology of scalar-tensor-vector gravity theory

Science.gov (United States)

Jamali, Sara; Roshan, Mahmood; Amendola, Luca

2018-01-01

We consider the cosmological consequences of a special scalar-tensor-vector theory of gravity, known as MOG (for MOdified Gravity), proposed to address the dark matter problem. This theory introduces two scalar fields G(x) and μ(x), and one vector field phiα(x), in addition to the metric tensor. We set the corresponding self-interaction potentials to zero, as in the standard form of MOG. Then using the phase space analysis in the flat Friedmann-Robertson-Walker background, we show that the theory possesses a viable sequence of cosmological epochs with acceptable time dependency for the cosmic scale factor. We also investigate MOG's potential as a dark energy model and show that extra fields in MOG cannot provide a late time accelerated expansion. Furthermore, using a dynamical system approach to solve the non-linear field equations numerically, we calculate the angular size of the sound horizon, i.e. θs, in MOG. We find that 8× 10‑3rad<θs<8.2× 10‑3 rad which is way outside the current observational bounds. Finally, we generalize MOG to a modified form called mMOG, and we find that mMOG passes the sound-horizon constraint. However, mMOG also cannot be considered as a dark energy model unless one adds a cosmological constant, and more importantly, the matter dominated era is still slightly different from the standard case.

Perspective of meson science

International Nuclear Information System (INIS)

Yamazaki, T.; Nagamine, K.

1992-01-01

Unstable particles such as mesons and muons are now used in various research domains of physics, chemistry, engineering, and life sciences. This book is aimed at summarizing the present exploratory activities and giving future perspectives from a very broad scope. It contains 27 contributions in a wide range of subjects, such as μSR studies of superconductivities, magnetism, muon beam and μSr methodology, theoretical accounts of muon hyperfine interactions, muon catalyzed fusion processes, metastable exotic atoms, medical diagnostics, strangeness nuclear physics, mesons in nuclei, meson-related nuclear reactions and structure, and exotic decays of mesons

PROPERTIES OF THE $omega$ MESON

Energy Technology Data Exchange (ETDEWEB)

Shafer, J. B.; Murray, J. J.; Ferro-Luzzi, M.; Huwe, D. O.

1963-06-15

Properties of the omega meson were studied from the reaction K/sup -/ + p yields LAMBDA + omega in a 72-in. hydrogen bubble chamber. The momentum of the K/sup -/ mesons was 1.2 to 1.75 Bev/c. The mass of the omega meson is found to be 782 Mev with a width, predominated by three-meson( pi ) decay mode, estimated to be less than 4 Mev. Branching ratios for omega -meson decay into pi /sup +/ pi /sup -/ pi /sup o/, pi /sup o/ gamma , pi /sup +/ i/ sup -/, and e/sup +/e/sup -o/ were determined. (R.E.U.)

Fully reconstructed B-meson decays using J/ψ and ψ(2S)

International Nuclear Information System (INIS)

Miao, Ting.

1996-09-01

In this paper we present CDF B-meson branching ratio results involving color-suppressed B → ΨΚ decays, where Ψ = J/ψ, ψ(2S) and Κ = Κ, Κ * . Fully reconstructed decays of B → J/ψΚ, B → ψ(2S)Κ, B + → J/ψπ + and B s → J/ψφ are used to extract branching ratios, vector-pseudoscalar ratios and polarization parameters

Probing the nuclear medium with the K+ meson

International Nuclear Information System (INIS)

Chrien, R.E.

1995-01-01

Elastic differential cross sections for K + mesons scattered from targets of carbon and 6 Li have been measured at an incident momentum of 715 MeV/c. The ratios of scattering cross sections from these targets are not predicted by theory, and are consistent with earlier suggestions that the K + -nucleon interaction is modified in the nuclear medium

Polarizations of J/psi and psi(2S) mesons produced in pp collisions at square root s = 1.96 TeV.

Science.gov (United States)

Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Daronco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dörr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Veramendi, G; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

2007-09-28

We have measured the polarizations of J/psi and psi(2S) mesons as functions of their transverse momentum p(T) when they are produced promptly in the rapidity range |y| or =5 GeV/c. The analysis is performed using a data sample with an integrated luminosity of about 800 pb(-1) collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as p(T) increases from 5 to 30 GeV/c. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of J/psi and psi(2S) mesons from B-hadron decays are also reported.

Relativistic scalar-vector models of the N-N and N-nuclear interactions

International Nuclear Information System (INIS)

Green, A.E.S.

1985-01-01

This paper for the Proceedings of Conference an Anti-Nucleon and Nucleon-Nucleus Interactions summarizes work by the principal investigator and his collaborators on the nucleon-nucleon (N-N) and nucleon-nuclear (N-eta) interactions. It draws heavily on a paper presented at the Many Body Conference in Rome in 1972 but also includes a brief review of our phenomenological N-eta interaction studies. We first summarize our 48-49 generalized scalar-vector meson field theory model of the N-N interactions. This is followed by a brief description of our phenomenological work in the 50's on the N-eta interaction sponsored by the Atomic Energy Commission (the present DOE). This work finally led to strong velocity dependent potentials with spin orbit and isospin terms for shell and optical model applications. This is followed by a section on the Emergence of One-Boson Exchange Models describing developments in the 60's of quantitative generalized one boson exchange potentials (GOBEP) including our purely relativistic N-N analyses. Then follows a section on the application of this meson field model to the N-eta interaction, in particular to spherical closed shell nuclei. This work was sponsored by AFOSR but funding was halted with the Mansfield amendment. We conclude with a discussion of subsequent collateral work by former colleagues and by others who have converged upon scalar-vector relativistic models of N-N, antiN-N, N-eta and antiN-eta interactions and some lessons learned from this extended endeavor. 61 refs