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Sample records for antibaryons

  1. Antibaryons bound in nuclei

    CERN Document Server

    Mishustin, I N; Buervenich, T J; Stöcker, H; Greiner, W

    2005-01-01

    We study the possibility of producing a new kind of nuclear systems which in addition to ordinary nucleons contain a few antibaryons (antiproton, antilambda, etc.). The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from He to Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by factor 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that due to significant reduction of the reaction Q-values, the in-medium annihilation rates should be strongly suppressed leading to relativel...

  2. Antibaryon-nucleus bound states

    CERN Document Server

    Hrtánková, J

    2014-01-01

    We calculated antibaryon ($\\bar{B}$ = $\\bar{p}$, $\\bar{\\Lambda}$, $\\bar{\\Sigma}$, $\\bar{\\Xi}$) bound states in selected nuclei within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{B}$-meson coupling constants were scaled to yield corresponding potentials consistent with available experimental data. Large polarization of the nuclear core caused by $\\bar{B}$ was confirmed. The $\\bar{p}$ annihilation in the nuclear medium was incorporated by including a phenomenological imaginary part of the optical potential. The calculations using a complex $\\bar{p}$-nucleus potential were performed fully self-consistently. The $\\bar{p}$ widths significantly decrease when the phase space reduction is considered for $\\bar{p}$ annihilation products, but they still remain sizeable for potentials consistent with $\\bar{p}$-atom data.

  3. BASE - The Baryon Antibaryon Symmetry Experiment

    CERN Document Server

    Smorra, C; Bojtar, L.; Borchert, M.; Franke, K.A.; Higuchi, T.; Leefer, N.; Nagahama, H.; Matsuda, Y.; Mooser, A.; Niemann, M.; Ospelkaus, C.; Quint, W.; Schneider, G.; Sellner, S.; Tanaka, T.; Van Gorp, S.; Walz, J.; Yamazaki, Y.; Ulmer, S.

    2015-01-01

    The Baryon Antibaryon Symmetry Experiment (BASE) aims at performing a stringent test of the combined charge parity and time reversal (CPT) symmetry by comparing the magnetic moments of the proton and the antiproton with high precision. Using single particles in a Penning trap, the proton/antiproton $g$-factors, i.e. the magnetic moment in units of the nuclear magneton, are determined by measuring the respective ratio of the spin-precession frequency to the cyclotron frequency. The spin precession frequency is measured by non-destructive detection of spin quantum transitions using the continuous Stern-Gerlach effect, and the cyclotron frequency is determined from the particle's motional eigenfrequencies in the Penning trap using the invariance theorem. By application of the double Penning-trap method we expect that in our measurements a fractional precision of $\\delta g/g$ 10$^{-9}$ can be achieved. The successful application of this method to the antiproton will represent a factor 1000 improvement in the frac...

  4. Importance of multimesonic fusion processes on (strange) antibaryon production

    CERN Document Server

    Greiner, C

    2002-01-01

    Sufficiently fast chemical equilibration of (strange) antibaryons in an environment of nucleons, pions and kaons during the course of a relativistic heavy ion collision can be understood by a `clustering' of mesons to built up baryon-antibaryon pairs. This multimesonic (fusion-type) process has to exist in medium due to the principle of detailed balance. Novel numerical calculations for a dynamical setup are presented. They show that at maximum SPS energies - yields of each antihyperon specie are obtained which are consistent with chemical saturated populations of T approximately=150-160 MeV, in line with popular chemical freeze-out parameters extracted from thermal model analyses. (17 refs).

  5. Antibaryon production in the central region at the ISR

    International Nuclear Information System (INIS)

    Using annihilation in a calorimeter as a trigger on antiprotons, we have measured the relative production cross sections of anti p, anti Λ and anti Ψ at γ approx.= 0 in the transverse momentum range 1 to 2 GeV/c in pp collisions at √s = 63 GeV. We investigate correlations between the antibaryons and associated produced particles, and find evidence for local baryon number conservation. (orig.)

  6. Experimental Status of Photon Photon into Baryon Antibaryon Pairs

    CERN Document Server

    Barillari, T

    2001-01-01

    The exclusive production of baryon antibaryon pairs in the collisions of two quasi-real photons have been studied in different experiments at e+e- colliders. Results are presented for the processes gamma gamma to proton antiproton and gamma gamma to lambda lambdabar. The cross-section measurements are compared with the available data and with the recent analytic calculations based on the quark-diquark model predictions. Monte Carlo studies have been done to investigate the PEP-N expectations for the gamma gamma to proton antiproton process.

  7. The topological approach to baryon-antibaryon and meson production in rapidly expanding Bjorken rods

    CERN Document Server

    Holzwarth, G

    2004-01-01

    The topological approach to baryon-antibaryon production in the chiral phase transition is numerically simulated for rapidly expanding hadronic systems. For that purpose the dynamics of the effective chiral field is implemented on a space - rapidity lattice. The essential features of evolutions from initial 'hot' configurations into final ensembles of (anti-)baryons embedded in the chiral condensate are studied in proper time of comoving frames. Typical times for onset and completion of the roll-down and exponents for the growth of correlations are extracted. Meson and baryon-antibaryon yields are estimated. For standard assumptions about initial coherence lengths they are compatible with experimental results.

  8. Hints for the existence of hexaquark states in the baryon-antibaryon sector

    OpenAIRE

    Abud, Mario; Buccella, Franco; Tramontano, Francesco

    2009-01-01

    The discovery of some baryon-antibaryon resonances has led us to consider 3q~3\\bar{q} systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromo-magnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge on tetraquarks. The emerging scenario complies well with experiment. Besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely the a0(Y) in ...

  9. Hints for the existence of hexaquark states in the baryon-antibaryon sector

    International Nuclear Information System (INIS)

    The discovery of some baryon-antibaryon resonances has led us to consider 3q 3q systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromomagnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge of tetraquarks. The emerging scenario complies well with experiment; besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely, the a0(Y) in the hidden strangeness sector and the Y(4140) and X(4350) in the cscs sector. A detailed account of the spectra and the decay channels is provided for future comparisons with data.

  10. Importance of multi-mesonic fusion processes on (strange) antibaryon production

    CERN Document Server

    Greiner, C

    2002-01-01

    Sufficiently fast chemical equilibration of (strange) antibaryons in an environment of nucleons, pions and kaons during the course of a relativistic heavy ion collision can be understood by a `clustering' of mesons to build up baryon-antibaryon pairs. This multi-mesonic (fusion-type) process has to exist in medium due to the principle of detailed balance. Novel numerical calculations for a dynamical setup are presented. They show that - at maximum SPS energies - yields of each antihyperon specie are obtained which are consistent with chemical saturated populations of T approximately 150-160 MeV, in line with popular chemical freeze-out parameters extracted from thermal model analyses.

  11. Hiding of the conserved (anti)baryonic charge into black holes

    International Nuclear Information System (INIS)

    It is shown that the total number of baryons evaporated by a black hole can differ from that of antibaryons, even if baryonic charge is microscopically conserved. The baryonic asymmetry of the Universe which can be generated by black-hole evaporation in a specific mechanism first proposed by Zeldovich is estimated

  12. Baryon--antibaryon pair decay of eta/sub c/ in coherent production

    International Nuclear Information System (INIS)

    The feasibility of observing eta/sub c/ by its OZI-rule-forbidden baryon-antibaryon pair decay in the coherent production (Primakoff effect) of eta/sub c/ is investigated. The cross sections are estimated as a function of photon energy, and the CM angular distribution is calculated

  13. Hints for the existence of hexaquark states in the baryon-antibaryon sector

    Science.gov (United States)

    Abud, Mario; Buccella, Franco; Tramontano, Francesco

    2010-04-01

    The discovery of some baryon-antibaryon resonances has led us to consider 3q 3q¯ systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromomagnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge of tetraquarks. The emerging scenario complies well with experiment; besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely, the a0(Y) in the hidden strangeness sector and the Y(4140) and X(4350) in the cscs¯ sector. A detailed account of the spectra and the decay channels is provided for future comparisons with data.

  14. Hints for the existence of hexaquark states in the baryon-antibaryon sector

    CERN Document Server

    Abud, Mario; Tramontano, Francesco

    2010-01-01

    The discovery of some baryon-antibaryon resonances has led us to consider 3q~3\\bar{q} systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromo-magnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge on tetraquarks. The emerging scenario complies well with experiment. Besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely the a0(Y) in the hidden strangeness sector and, in the cs\\bar{c}\\bar{s} sector, the Y(4140) and the X(4350). A detailed account of the spectra and the decay channels is provided for future comparisons with data.

  15. Exclusive Baryon-Antibaryon Decays of the chi_cJ Mesons

    CERN Document Server

    Naik, P; Asner, D M; Edwards, K W; Reed, J; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hunt, J M; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Ledoux, J; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; Méndez, H; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A

    2008-01-01

    Using a sample of 2.59 \\times 10^7 psi(2S) decays collected by the CLEO--c detector, we present results of a study of chi_{cJ} (J=0,1,2) decays into baryon-antibaryon final states. We present the world's most precise measurements of the chi_cJ -> p-pbar and chi_cJ -> Lambda-Lambdabar branching fractions, and the first measurements of chi_c0 decays to other hyperons. These results illuminate the decay mechanism of the chi_c states.

  16. Strange and non-strange baryon and antibaryon production in sulphur-tungsten and sulphur-sulphur interactions at 200 A Gev/c

    International Nuclear Information System (INIS)

    The author has studied production of strange and multistrange baryons and antibaryons in central sulphur-tungsten, sulphur-sulphur, and lead-lead interactions at relativistic energies. The spectra of strange baryons and antibaryons provide information about the dynamics of hadronic matter under the extreme conditions realised in these collisions. The particle ratios allow the degree and the nature of the flavour equilibrium to be studied, while the transverse mass distributions provide independent information of the temperatures achieved. 143 refs

  17. Baryon-antibaryon asymmetry in central rapidity region at LHC with the ALICE experiment

    CERN Document Server

    Broz, Michal

    The Large Hadron Collider (LHC) provided the first proton-proton collisions in the period of November-December 2009. Since then, a large data sample has been recorded by all LHC experiments. This event sample allows us to study more and more exotic particles and events. The ALICE (A Large Ion Collider Experiment) experiment, though designed primarily to study heavy ion collisions, has a rich proton-proton physics program. The characteristic features of ALICE are its very low-momentum cut-off, the low material budget and the excellent particle identification (PID) and vertexing capabilities. In this thesis, I discuss the results from the analysis of proton-proton collisions at the different LHC energies (√s = 900 GeV, 2.76 TeV and 7 TeV). I concentrate on the antibaryon-to-baryon ratio study which is of great importance for description of baryon number transport and it can allow to determine the carrier of the baryon number as well as to give an information on baryon structure itself. In particular, the mult...

  18. Study of ψ(3770) decaying to baryon anti-baryon pairs

    Science.gov (United States)

    Xia, Li-Gang

    2016-05-01

    To study the decays of ψ (3770) going to baryon anti-baryon pairs (B B bar), all available experiments of measuring the cross sections of e+e- → B B bar at center-of-mass energy ranging from 3.0 GeV to 3.9 GeV are combined. To relate the baryon octets, a model based on the SU(3) flavor symmetry is used and the SU(3) breaking effects are also considered. Assuming the electric and magnetic form factors are equal (|GE | = |GM |), a global fit including the interference between the QED process and the resonant process is performed. The branching fraction of ψ (3770) → B B bar is determined to be (2.4 ± 0.8 ± 0.3) ×10-5, (1.7 ± 0.6 ± 0.1) ×10-5, (4.5 ± 0.9 ± 0.1) ×10-5, (4.5 ± 0.9 ± 0.1) ×10-5, (2.0 ± 0.7 ± 0.1) ×10-5, and (2.0 ± 0.7 ± 0.1) ×10-5 for B = p , Λ ,Σ+ ,Σ0 ,Ξ- and Ξ0, respectively, where the first uncertainty is from the global fit and the second uncertainty is the systematic uncertainty due to the assumption |GE | = |GM |. They are at least one order of magnitude larger than a simple scaling of the branching fraction of J / ψ / ψ (3686) → B B bar .

  19. Study of ψ(3770 decaying to baryon anti-baryon pairs

    Directory of Open Access Journals (Sweden)

    Li-Gang Xia

    2016-05-01

    Full Text Available To study the decays of ψ(3770 going to baryon anti-baryon pairs (BB¯, all available experiments of measuring the cross sections of e+e−→BB¯ at center-of-mass energy ranging from 3.0 GeV to 3.9 GeV are combined. To relate the baryon octets, a model based on the SU(3 flavor symmetry is used and the SU(3 breaking effects are also considered. Assuming the electric and magnetic form factors are equal (|GE|=|GM|, a global fit including the interference between the QED process and the resonant process is performed. The branching fraction of ψ(3770→BB¯ is determined to be (2.4±0.8±0.3×10−5, (1.7±0.6±0.1×10−5, (4.5±0.9±0.1×10−5, (4.5±0.9±0.1×10−5, (2.0±0.7±0.1×10−5, and (2.0±0.7±0.1×10−5 for B=p,Λ,Σ+,Σ0,Ξ− and Ξ0, respectively, where the first uncertainty is from the global fit and the second uncertainty is the systematic uncertainty due to the assumption |GE|=|GM|. They are at least one order of magnitude larger than a simple scaling of the branching fraction of J/ψ/ψ(3686→BB¯.

  20. On Baryon-Antibaryon Cross Sections from Initial State Radiation Processes at BABAR and their Surprising Threshold Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Pacetti, Simone [Enrico Fermi Center, Rome (Italy); National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LFN). et al.

    2015-04-14

    BABAR has measured with unprecedented accuracy the e+e- → pp-bar and e+e- → ΛΛ-bar cross sections by means of the initial state radiation technique, which has the advantages of good efficiency and energy resolution, and full angular acceptance in the threshold region. A striking feature of these cross sections is their non-vanishing values at threshold. In the case of charged baryons, the phenomenon is well understood in terms of the Coulomb interaction between the outgoing baryon and antibaryon. However, such an effect is not expected for neutral baryons. We suggest a simple explanation for both charged and neutral baryon pairs based on Coulomb interactions at the valence quark level.

  1. Antibaryon-nucleus bound states

    Czech Academy of Sciences Publication Activity Database

    Hrtánková, Jaroslava; Mareš, Jiří

    Vol. 599. Bristol: IOP, 2015, 012007. ISSN 1742-6588. [3rd Workshop on FAIRNESS - FAIR Next Generation Scientists. Vierti sul Mare (IT), 22.09.2014-27.09.2014] R&D Projects: GA ČR(CZ) GAP203/12/2126 Institutional support: RVO:61389005 Keywords : Sigma * potentials Subject RIV: BE - Theoretical Physics

  2. Mid-rapidity anti-baryon to baryon ratios in pp collisions at $\\sqrt{s}$ = 0.9, 2.76 and 7 TeV measured by ALICE

    CERN Document Server

    Abbas, Ehab; Adam, Jaroslav; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agocs, Andras Gabor; Agostinelli, Andrea; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahmed, Ijaz; Ahn, Sul-Ah; Ahn, Sang Un; Aimo, Ilaria; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Nicola; Bianchi, Livio; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Boccioli, Marco; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bossu, Francesco; Botje, Michiel; Botta, Elena; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carlin Filho, Nelson; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Castillo Hernandez, Juan Francisco; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio; Colella, Domenico; Collu, Alberto; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Connors, Megan Elizabeth; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crescio, Elisabetta; Crochet, Philippe; Cruz Alaniz, Emilia; Cruz Albino, Rigoberto; Cuautle, Eleazar; Cunqueiro, Leticia; Dainese, Andrea; Dang, Ruina; Danu, Andrea; Das, Kushal; Das, Supriya; Das, Debasish; Das, Indranil; Dash, Sadhana; Dash, Ajay Kumar; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; Delagrange, Hugues; Deloff, Andrzej; De Marco, Nora; Denes, Ervin; De Pasquale, Salvatore; Deppman, Airton; D'Erasmo, Ginevra; de Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Di Bari, Domenico; Dietel, Thomas; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, AK; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erazmus, Barbara; Erdal, Hege Austrheim; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floratos, Emmanuel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Gargiulo, Corrado; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Costin; Grigoras, Alina Gabriela; Grigoriev, Vladislav; Grigoryan, Smbat; Grigoryan, Ara; Grinyov, Boris; Grion, Nevio; Gros, Philippe; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Han, Byounghee; Hanratty, Luke David; Hansen, Alexander; Harmanova, Zuzana; Harris, John William; Hartig, Matthias; Harton, Austin; Hatzifotiadou, Despoina; Hayashi, Shinichi; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard; Hippolyte, Boris; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hwang, Dae Sung; Ichou, Raphaelle; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Pier Giorgio; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Marian; Ivanov, Andrey; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacholkowski, Adam Wlodzimierz; Jacobs, Peter; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kaidalov, Alexei; Kalcher, Sebastian; Kalinak, Peter; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Ketzer, Bernhard Franz; Khan, Palash; Khan, Kamal Hussain; Khan, Shuaib Ahmad; Khan, Mohisin Mohammed; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Do Won; Kim, Taesoo; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Beomkyu; Kim, Jin Sook; Kim, Jonghyun; Kim, Dong Jo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kliemant, Michael; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kohler, Markus; Kollegger, Thorsten; Kolojvari, Anatoly; Kompaniets, Mikhail; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucera, Vit; Kucheriaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paul; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasily; Kvaerno, Henning; Kweon, Min Jung; Kwon, Youngil; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; La Pointe, Sarah Louise; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; La Rocca, Paola; Lea, Ramona; Lechman, Mateusz; Lee, Sung Chul; Lee, Graham Richard; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenhardt, Matthieu Laurent; Lenti, Vito; Leon, Hermes; Leoncino, Marco; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Loenne, Per-Ivar; Loggins, Vera; Loginov, Vitaly; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luzzi, Cinzia; Ma, Rongrong; Ma, Ke; Madagodahettige-Don, Dilan Minthaka; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Mangotra, Lalit Kumar; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mizuno, Sanshiro; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Ochirov, Alexander; Oeschler, Helmut Oskar; Oh, Sun Kun; Oh, Saehanseul; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Ostrowski, Piotr Krystian; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozawa, Kyoichiro; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Paul, Biswarup; Pavlinov, Alexei; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitri; Perez Lara, Carlos Eugenio; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piyarathna, Danthasinghe; Planinic, Mirko; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pocheptsov, Timur; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polak, Karel; Polichtchouk, Boris; Poljak, Nikola; Pop, Amalia; Porteboeuf-Houssais, Sarah; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Punin, Valery; Putis, Marian; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Sudhir; Raniwala, Rashmi; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Rauch, Wolfgang; Rauf, Aamer Wali; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick; Reicher, Martijn; Reidt, Felix; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rogochaya, Elena; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Santoro, Romualdo; Sarkamo, Juho Jaako; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Hans Rudolf; Schmidt, Christian Joachim; Schuchmann, Simone; Schukraft, Jurgen; Schuster, Tim; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Patrick Aaron; Scott, Rebecca; Segato, Gianfranco; Selyuzhenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Satish; Sharma, Natasha; Sharma, Rohni; Shigaki, Kenta; Shtejer, Katherin; Sibiriak, Yury; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Tinku; Sinha, Bikash; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Ter-Minasyan, Astkhik; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Tlusty, David; Toia, Alberica; Torii, Hisayuki; Toscano, Luca; Trubnikov, Victor; Truesdale, David Christopher; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; Van Hoorne, Jacobus Willem; van Leeuwen, Marco; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Yury; Vinogradov, Alexander; Vinogradov, Leonid; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wan, Renzhuo; Wang, Yifei; Wang, Yaping; Wang, Mengliang; Watanabe, Kengo; Weber, Michael; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Winn; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Ping; Yang, Hongyan; Yang, Shiming; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Yonghong; Zhang, Xiaoming; Zhou, You; Zhou, Daicui; Zhou, Fengchu; Zhu, Jianlin; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

    2013-01-01

    The ratios of yields of anti-baryons to baryons probes the mechanisms of baryon-number transport. Results for anti-proton/proton, anti-$\\Lambda/\\Lambda$, anti-$\\Xi^{+}/\\Xi^{-}$ and anti-$\\Omega^{+}/\\Omega^{-}$ in pp collisions at $\\sqrt{s}$ = 0.9, 2.76 and 7 TeV, measured with the ALICE detector at the LHC, are reported. Within the experimental uncertainties and ranges covered by our measurement, these ratios are independent of rapidity, transverse momentum and multiplicity for all measured energies. The results are compared to expectations from event generators, such as PYTHIA and HIJING/B, that are used to model the particle production in pp collisions. The energy dependence of anti-proton/proton, anti-$\\Lambda/\\Lambda$, anti-$\\Xi^{+}/\\Xi^{-}$ and anti-$\\Omega^{+}/\\Omega^{-}$, reaching values compatible with unity for $\\sqrt{s}$ = 7 TeV, complement the earlier anti-proton/proton measurement of ALICE. These dependencies can be described by exchanges with the Regge-trajectory intercept of $\\alpha_J$ ≈ 0.5, ...

  3. Quasinuclear states in baryon-antibaryon systems

    International Nuclear Information System (INIS)

    A review of modern state of physics of quasinuclear baryon-antibarion systems (''baryonium'') is presented. The comparison between the theory predictions and recent experimental data is carried out. Discrete γ - spectrum from the anti pp annihilation, annihilation and elastic widths for N anti N resonances from experiments with hydrogen and deuterium targets, proton form factor and e+e- annihilation in the vicinity of N anti N threshold are considered. The most important future experiments on antiproton annihilation in nuclear targers are discussed. Experiments which may reveal the existences of 2B anti B and 2B anti 2B systems are predicted

  4. Results on baryon antibaryon correlations in e+e--annihilation

    International Nuclear Information System (INIS)

    The correlations between panti p, Λanti Λ, Ξ-anti Λ and Λ(1520)anti Λ baryons have been measured in e+e- continuum events and in direct Υ decays. The observed correlations exclude the production of point-like diquark-antidiquark pairs as the dominant source of baryons. Information concerning angular momentum compensation follows from the observed Λ(1520)anti Λ correlation. (orig.)

  5. Baryon-antibaryon asymmetry in a model with domain structure and soft CP violation

    International Nuclear Information System (INIS)

    We consider a model with an abelian gauge symmetry, a Higgs potential involving two scalar fields, and two spinor fields coupled to the scalars through Yukawa couplings. The model accomodates soft violation of charge conjugation, and a domain structure of the universe with two different types of domains, which have identical energy but are governed by different effective lagrangians. The effective lagrangian has complex c-number coefficients that become parts of effective coupling constants, and these are different in the two kinds of domains. In spite of that fact the model neither predicts any domain-dependent effects, nor any particle-antiparticle asymmetries within domains. (orig.)

  6. Relevance of baryon-antibaryon decays of Bd0, anti Bd0 in tests of CP violation

    International Nuclear Information System (INIS)

    The decays of the type Bd0, anti Bd0→panti p, Λanti Λ, ΛC+anti ΛC+, into a spin 1/2 baryon and its antiparticle proceed in both the S-wave (parity conversing) and the P-wave (parity violating), and the final state is not an eigenstate of CP. Generalizing the type of tests of CP violation first proposed by Sanda et al., the CP violating asymmetries are proportional to ΓS-ΓP. We compute the parity conserving and the parity violating amplitudes within a pole model. The ratio ΓS/ΓP is of O(1) for panti p, but we find the selection rule ΓS=0 for Λanti Λ, and ΓP≤ΓS for ΛC+anti ΛC+. For the modes panti p and Λanti Λ, where the detection efficiency is large, we estimate the number of Bd0, anti Bd0 pairs needed to observe the CP asymmetries at the 3σ level to be of the order 1010. (orig.)

  7. Study of Baryon and Antibaryon Spectra in Lead Lead Interactions at 160 GeV/c per Nucleon

    CERN Multimedia

    2002-01-01

    % WA97 \\\\ \\\\ Hyperons are expected to be a useful probe for the dynamics of hadronic matter under extreme conditions. In particular the onset of a Quark-Gluon Plasma phase in a heavy ion collision is expected to enhance the hyperon yield with respect to normal hadronic interactions. \\\\ \\\\WA97 aims to measure the spectra of strange particles and in particular of hyperons and antihyperons produced in ultrarelativistic lead-lead interactions and to compare them with those from proton initiated reactions. The experiment covers central rapidity down to transverse momenta of a few hundred MeV/c. The experimental setup consists of: an array of multiplicity counters, a silicon based decay detector made of pixels, located in the CERN-OMEGA Spectrometer, an array of pad cathode MWPCs used as lever arm detectors and a zero degree hadron calorimeter. \\\\ \\\\

  8. Decay into strange baryon-antibaryon pairs and an I-spin determination of the psi(3095)

    International Nuclear Information System (INIS)

    Data are given for PSI(3095) decay into Λ anti Λ, and some evidence is shown for the channels Σ anti Σ and possibly Ψ anti Ψ. The final states Σ anti Σ and Ψ anti Ψ are ambiguous with Λ anti ΛX0, for example, Λ anti Λπ0. The decay PSI(3095) → Λ anti Λ is of particular interest because the Λ anti Λ pair is in a pure I = 0 state. It is shown that this decay proceeds directly rather than through an intermediate γ, and thus one obtains a determination of the isospin of the PSI(3095). (JFP)

  9. Mid-rapidity anti-baryon to baryon ratios in pp collisions at root s=0.9, 2.76 and 7 TeV measured by ALICE

    Czech Academy of Sciences Publication Activity Database

    Abbas, E.; Abelev, B.; Adam, J.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Čepila, J.; Křelina, M.; Krus, M.; Kučera, Vít; Kushpil, Svetlana; Kushpil, Vasilij; Mareš, Jiří A.; Pachr, M.; Petráček, V.; Petráň, M.; Polák, Karel; Pospíšil, V.; Šmakal, R.; Šumbera, Michal; Tlustý, D.; Vajzer, Michal; Wagner, V.; Zach, Č.; Závada, Petr

    2013-01-01

    Roč. 73, č. 7 (2013), s. 2496. ISSN 1434-6044 R&D Projects: GA MŠk LA08015; GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE * heavy ion collisions Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) Impact factor: 5.436, year: 2013 http://download.springer.com/static/pdf/389/art%253A10.1140%252Fepjc%252Fs10052-013-2496-5.pdf?auth66=1379854432_f726318e642cdcbe3735b0baa31b020a&ext=.pdf

  10. Confining bond rearrangement in the random center vortex model

    Science.gov (United States)

    Altarawneh, Derar; Höllwieser, Roman; Engelhardt, Michael

    2016-03-01

    We present static meson-meson and baryon-antibaryon potentials in Z (2 ) and Z (3 ) random center vortex models for the infrared sector of Yang-Mills theory, i.e., hypercubic lattice models of random vortex world surfaces. In particular, we calculate multiple Polyakov loop correlators corresponding to static meson-meson or baryon-antibaryon configurations in a center vortex background and observe that their expectation values follow the minimal area law, displaying bond rearrangement behavior, a characteristic expected for the confining dynamics of the strong interaction. The static meson-meson and baryon-antibaryon potentials are compared with theoretical predictions and lattice QCD simulations.

  11. Baryon production in $e^{+}e^{-}$-annihilation at PETRA

    CERN Document Server

    Bartel, Wulfrin; Dittmann, P; Eichler, R; Felst, R; Haidt, Dieter; Krehbiel, H; Meier, K; Naroska, Beate; O'Neill, L H; Steffen, P; Wenninger, Horst; Zhang, Y; Elsen, E E; Helm, M; Petersen, A; Warming, P; Weber, G; Bethke, Siegfried; Drumm, H; Heintze, J; Heinzelmann, G; Hellenbrand, K H; Heuer, R D; Von Krogh, J; Lennert, P; Kawabata, S; Matsumura, H; Nozaki, T; Olsson, J; Rieseberg, H; Wagner, A; Bell, A; Foster, F; Hughes, G; Wriedt, H; Allison, J; Ball, A H; Bamford, G; Barlow, R; Bowdery, C K; Duerdoth, I P; Hassard, J F; King, B T; Loebinger, F K; MacBeth, A A; McCann, H; Mills, H E; Murphy, P G; Prosper, H B; Stephens, K; Clarke, D; Goddard, M C; Marshall, R; Pearce, G F; Kobayashi, T; Komamiya, S; Koshiba, M; Minowa, M; Nozaki, M; Orito, S; Sato, A; Suda, T; Takeda, H; Totsuka, Y; Watanabe, Y; Yamada, S; Yanagisawa, C

    1981-01-01

    Data on p and Lambda production by e/sup +/e/sup -/-annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon-antibaryon pairs is seen.

  12. Strange baryon production in Pb-Pb interactions at CERN SPS

    CERN Document Server

    Sándor, L; Bacon, P A; Badalà, A; Barbera, R; Belogianni, A; Bhasin, A; Bloodworth, I J; Bombara, M; Bruno, G E; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; Dainese, A; De Haash, A P; De Rijke, P; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Feofilov, G A; Fini, R A; Ganoti, P; Ghidini, B; Grella, G; Helstrup, H; Henriquez, M; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratiev, V; Králik, I; Kravcakova, A; Kuijer, P; Lenti, V; Lietava, R; Løvhøiden, G; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Spyropoulou-Stassinaki, M; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Vyvre, P V; van Eijndhoven, N; Van Hunen, J; Vascotto, A; Vik, T; Villalobos Baillie, O; Vinogradov, L; Virgili, T; Votruba, M F; Vrláková, J; Závada, P

    2004-01-01

    Recent results on strange baryon and antibaryon production in Pb-Pb collisions at 160 GeV per nucleon from the NA57 experiment are reported. Strangeness enhancements and the transverse mass spectra properties are described.

  13. Baryon production in e+e--annihilation at PETRA

    International Nuclear Information System (INIS)

    Data on anti p and anti Λ production by e+e--annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon antibaryon pairs is seen. (orig.)

  14. Quantum evaporation of black holes and the baryon asymmetry of the Universe

    International Nuclear Information System (INIS)

    It is shown that unstable A particles, evaporated from a black hole and decaying in its gravitational field, can lead to an excess of baryons over antibaryons in the space outside. The effect is due to the violation of C and CP invariance in the decays of the A particle into a heavy baryon and a light antibaryon and in the charge-conjugate mode, and also to the difference between the probabilities of recapture of heavy and light particles by the black hole. For this mechanism there is no need for violation of the law of conservation of baryon charge

  15. Strange anti-baryons---QGP versus HC

    International Nuclear Information System (INIS)

    We study quark-gluon plasma (QGP) and hadronic gas (HG) models of the central fireball presumed to be the source of abundantly produced strange (anti-)baryons in S→W collisions at 200 GeV A. We consider how multi-strange (anti-)baryon multiplicities depend on strangeness conservation and compare the HG and QGP fireball scenarios. We argue that the total particle multiplicity emerging from the central rapidity region as well as the variation of production rates with changes in the beam energy allows to distinguish between the two reaction scenarios

  16. Anti-proton production and annihilation in nuclear collisions at 15-A/GeV

    OpenAIRE

    Jahns, André; Stöcker, Horst; Greiner, Walter; Sorge, Heinz

    2006-01-01

    We present a calculation of antiproton yields in Si+Al and Si+Au collisions at 14.5A GeV in the framework of the relativistic quantum molecular dynamics approach (RQMD). Multistep processes lead to the formation of high-mass flux tubes. Their decay dominates the initial antibaryon yield. However, the subsequent annihilation in the surrounding baryon-rich matter suppresses the antiproton yield considerably: Two-thirds of all antibaryons are annihilated even for the light Si+Al system. Comparis...

  17. Baryon Production in the String Fragmentation Picture

    OpenAIRE

    Eden, Patrik; Gustafson, Gosta

    1996-01-01

    An improved version of the ``pop-corn'' model for baryon production in quark and gluon jets is presented. With a reduced number of parameters the model reproduces well both production rates for different baryon species and baryon momentum distributions. Predictions are presented for a set of baryon-antibaryon correlations.

  18. Exotic N anti N resonances

    International Nuclear Information System (INIS)

    Some experimental suggestions for detecting exotic N anti N resonances were previously reviewed. Some additional possibilities not directly related to bump hunting are mentioned. The discussion includes the magnitude of Reggeon-exchange contributions to baryon--antibaryon total cross sections, the smallness of S-wave annihilation rates, and the precision of symmetry description of anti NN annihilations at rest

  19. Results from Pb-beam experiments at CERN

    International Nuclear Information System (INIS)

    Conditions of the collisions induced by Pb projectiles at 158 GeV/nucleon are reviewed. Three potential signatures of the formation of a quark-gluon plasma will be discussed: production of J/ψ and ψ' resonances, of virtual photons and of multi strange baryons and antibaryons. (author)

  20. Pion and proton spectra in 32S+S collisions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Rapidity spectra of pions and participant protons in S + S collisions at 200 GeV/nucleon are comparecd with N + N data. The average energy loss of the participating nucleons increases by 23% and is balanced by the energy of the final state particles through a twofold increase of strange particle production and a similar enhancement, assumed for baryon-antibaryon pairs. (orig.)

  1. Melting hadrons, boiling quarks

    Energy Technology Data Exchange (ETDEWEB)

    Rafelski, Johann [CERN-PH/TH, Geneva 23 (Switzerland); The University of Arizona, Department of Physics, Tucson, Arizona (United States)

    2015-09-15

    In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. The material of this review is complemented by two early and unpublished reports containing the prediction of the different forms of hadron matter, and of the formation of QGP in relativistic heavy ion collisions, including the discussion of strangeness, and in particular strange antibaryon signature of QGP. (orig.)

  2. Melting Hadrons, Boiling Quarks

    CERN Document Server

    Rafelski, Johann

    2015-01-01

    In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. Finally in two appendices I present previously unpublished reports describing the early prediction of the different forms of hadron matter and of the formation of QGP in relativistic heavy ion collisions, including the initial prediction of strangeness and in particular strange antibaryon signature of QGP.

  3. Empirical description of the hadron-hadron and hadron-nucleus interaction at the accelerator energy range

    Science.gov (United States)

    Kubiak, G.; Szabelski, J.; Wdowczyk, J.; Kempa, J.; Piotrowska, A.

    1985-01-01

    Taking into account several assumptions, a formula is transformed into two expressions for kaon and baryon plus antibaryon production in proton interaction and for pion production in pion interactions. Combining both formulae, expression are obtained for the spectrum of kaons and baryons plus antibaryons produced in the meson interactions. For analysis of the cosmic ray propagation in the atmosphere in actual fact, instead of the formulae for interactions of protons and mesons with protons, formulae appropriate for interactions with air nuclei was used. Using the method outlined among others by Elias et al. (1980) simple corrections were introduced to the derived expressions to account for the fact that the target is an air nucleus.

  4. Baryon femtoscopy considering residual correlations as a tool to extract strong interaction potentials

    Directory of Open Access Journals (Sweden)

    Szymański Maciej

    2015-01-01

    Full Text Available In this article, the analysis of baryon-antibaryon femtoscopic correlations is presented. In particular, it is shown that taking into account residual correlations is crucial for the description of pΛ¯$\\bar \\Lambda $ and p̄Λ correlation functions measured by the STAR experiment in Au–Au collisions at the centre-of-mass energy per nucleon pair √sNN = 200 GeV. This approach enables to obtain pΛ¯$\\bar \\Lambda $ (p̄Λ source size consistent with the sizes extracted from correlations in pΛ (p̄Λ¯$\\bar \\Lambda $ and lighter pair systems as well as with model predictions. Moreover, with this analysis it is possible to derive the unknown parameters of the strong interaction potential for baryon-antibaryon pairs under several assumptions.

  5. Measurement of inclusive baryon production in B meson decays

    International Nuclear Information System (INIS)

    Using the ARGUS detector at the e+e- storage ring DORIS II at DESY, we have studied B meson decays into baryons p and Λ. From the simultaneous analysis of p and Λ yields, panti p and Λanti p correlations, and various lepton-baryon and lepton-baryon-antibaryon correlations the inclusive branching ratio is found to be BR (B→baryons)=(6.8±0.5±0.3)%. (orig.)

  6. Hadron production in the quark combinatorics with color quarks

    International Nuclear Information System (INIS)

    An effect of color quark correlations on the M:B:anti B ratio of meson, baryon and antibaryon yields in the case of multiple hadron production is considered. It is shown that when the quark baryon number reveals itself like the probability of baryon state production of the quark, the M:B:anti B ratio in the central region weakly depends on the color correlations, and it is close to the value obtained earlier without account for the color quark states

  7. Elliptic flow of identified hadrons in Au+Au collisions at √(sNN)=200 GeV

    International Nuclear Information System (INIS)

    The anisotropy parameter (v2), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at √(sNN)=200 GeV for identified and inclusive charged particle production at central rapidities (|η|2 of mesons falls below that of (anti)baryons for pT>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated

  8. Peculiarities occurrence and microstrip gas chambers studied through experiment WA97; La production d`etrangete et les chambres gazeuses a micropistes dans le cadre de l`experience WA97

    Energy Technology Data Exchange (ETDEWEB)

    Kachelhoffer, T.

    1995-04-01

    This paper presents the studies on development of a Monte-Carlo type generator used for inclusive production of odd baryons and antibaryons through proton- proton and proton- nucleus collisions. Experiment WA97 consisted in designing simulation software for MSGCs (Micro-strips Gas Chambers) as well as the redefining of particle paths with the help of these chambers. This work made it possible to design the MSGC detector for experiment WA97. (TEC). 71 refs., 88 figs.

  9. Hyperon production in 158 and 40 A GeV/c Pb-Pb and p-Be collisions from the NA57 experiment

    CERN Document Server

    Elia, D; Bacon, P A; Badalà, A; Villalobos Baillie, O; Barbera, R; Belogianni, A; Bhasin, A; Bloodworth, Ian J; Bombara, M; Bruno, G E; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; Dainese, A; Di Bari, D; Di Liberto, S; Divià, R; Evans, D; Fanebust, K; Feofilov, G A; Fini, R A; Ganoti, P; Ghidini, B; Grella, G; Helstrup, H; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratiev, V; Králik, I; Kravcakova, A; Kuijer, P; Lenti, V; Lietava, R; Løvhøiden, G; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Spyropoulou-Stassinaki, M; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F; Van de Vyvre, P; Vascotto, Alessandro; Vik, T; Vinogradov, L I; Virgili, T; Votruba, M F; Vrláková, J; Závada, P; De Haas, A P; De Rijke, P C; van Eijndhoven, N; Van Hunen, J J; Van de Ven, P; Van den Brink, A

    2004-01-01

    The NA57 experiment at the CERN SPS has measured strange baryon and antibaryon production in Pb-Pb collisions with 158 and 40 A GeV/c beam momenta. Recent results on Lambda , Xi and Omega hyperon enhancements and from the transverse mass spectra analysis for the 158 A GeV/c data sample are presented. The energy dependence of hyperon production at midrapidity is discussed.

  10. Hyperon production in 158 and 40 A GeV/c Pb-Pb and p-Be collisions from the NA57 experiment

    International Nuclear Information System (INIS)

    The NA57 experiment at the CERN SPS has measured strange baryon and antibaryon production in Pb-Pb collisions with 158 and 40 A GeV/c beam momenta. Recent results on Λ, Ξ and Ω hyperon enhancements and from the transverse mass spectra analysis for the 158 A GeV/c data sample are presented. The energy dependence of hyperon production at mid-rapidity is discussed

  11. New results on strange and multistrange baryon production and charged kaon production in sulphur sulphur interactions at 200 GeV/c per nucleon

    International Nuclear Information System (INIS)

    Strange and multistrange baryon and antibaryon production has been studied in sulphur sulphur interactions at 200 GeV/c per nucleon at central rapidity. Particle production ratios and transverse mass spectra are presented for Λ, Ξ-, bar Ξ and bar Ξ-. In addition preliminary results on charged kaon production are presented, and the status of identified charged particle track reconstruction using the Omega RICH is reviewed. copyright 1995 American Institute of Physics

  12. High energy particle physics at Purdue. Annual technical progress report, March 1982-March 1983

    International Nuclear Information System (INIS)

    Progress is reported in these areas: a study of electron-positron annihilation using the High Resolution Spectrometer at SLAC; proton decay; extensive muon showers; gamma ray astronomy; the DUMAND project; theoretical work on fundamental problems in electromagnetic, weak, strong, and gravitational interactions; chi production by hadrons; p-nucleus interactions; development of the Collider Detector at Fermilab; and study of the observed hadrons as the relativistic bound states of baryons and antibaryons

  13. Physics with antiprotons at LEAR in the ACOL ERA. Proceedings of the 3. LEAR Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Gastaldi, U.; Klapisch, R.; Richard, J.M.; Tran Thanh Van, J. (eds.)

    1985-01-01

    The programme covered the following topics: accelerator aspects (anti-p production, LEAR, advanced developments, cooling, LEAR design inspired machines). Nucleon antinucleon interactions (panti-p atom, scattering, annihilation, spin effects, antineutron physics, antibaryon physics). Spectroscopy (light mesons, hybrids, glueballs, baryonia, quarkonia). Rare channels (form factors, CP, CPT, C, T violation, quantum mechanics tests) anti-p nucleus interactions (exotic atoms, scattering, annihilation, hypernuclei). New ideas (antigravity, high precision experiments). New detectors (new experiments, general and/or technical aspects).

  14. Physics with antiprotons at LEAR in the ACOL ERA

    International Nuclear Information System (INIS)

    The programme covered the following topics: accelerator aspects (anti-p production, LEAR, advanced developments, cooling, LEAR design inspired machines). Nucleon antinucleon interactions (panti-p atom, scattering, annihilation, spin effects, antineutron physics, antibaryon physics). Spectroscopy (light mesons, hybrids, glueballs, baryonia, quarkonia). Rare channels (form factors, CP, CPT, C, T violation, quantum mechanics tests) anti-p nucleus interactions (exotic atoms, scattering, annihilation, hypernuclei). New ideas (antigravity, high precision experiments). New detectors (new experiments, general and/or technical aspects)

  15. Detailed Discussion of a linear electric field frequency shift induced in confined gases by a magnetic field gradient: Implications for neutron electric dipole moment experiments

    OpenAIRE

    Lamoreaux, S. K.; Golub, R.

    2004-01-01

    The search for particle electric dipole moments (edm) is one of the best places to look for physics beyond the standard model because the size of time reversal violation predicted by the standard model is incompatible with present ideas concerning the creation of the Baryon-Antibaryon asymmetry. As the sensitivity of these edm searches increases more subtle systematic effects become important. We develop a general analytical approach to describe a systematic effect recently observed in an ele...

  16. Midrapidity hyperon production in pp and pA collisions from low to LHC energies

    International Nuclear Information System (INIS)

    The experimental data on p, Λ, Ξ-, Ω- -baryons and the corresponding antibaryons spectra obtained by different collaborations are compared with the results of the calculations performed into the frame of the quark-gluon string model. The contribution of string junction diffusion and the inelastic screening corrections are accounted for in the theoretical calculations. The predictions of the quark-gluon string model both for pp and pA collisions are extended up to the LHC energies. (orig.)

  17. Limits on Cosmic Matter--Antimatter Domains from Big Bang Nucleosynthesis

    OpenAIRE

    Rehm, Jan B.; Jedamzik, Karsten

    2000-01-01

    We present detailed numerical calculations of the light element abundances synthesized in a Universe consisting of matter- and antimatter- domains, as predicted to arise in some electroweak baryogenesis scenarios. In our simulations all relevant physical effects, such as baryon-antibaryon annihilations, production of secondary particles during annihilations, baryon diffusion, and hydrodynamic processes are coupled to the nuclear reaction network. We identify two dominant effects, according to...

  18. A new high sensitivity search for neutron-antineutron oscillations at the ESS

    OpenAIRE

    Milstead, David

    2015-01-01

    A sensitive search for neutron-antineutron oscillations can provide a unique probe of some of the central questions in particle physics and cosmology: the energy scale and mechanism for baryon number violation, the origin of the baryon-antibaryon asymmetry of the universe, and the mechanism for neutrino mass generation. A remarkable opportunity has emerged to search for such oscillations with the construction of the European Spallation Source (ESS). A collaboration has been formed which has p...

  19. Results from experiment E917 for Au + Au collisions at the AGS

    International Nuclear Information System (INIS)

    The effects of baryon stopping and its resulting energy deposition on the dynamics of Au + Au collisions at 6, 8 and 10.8 GeV/nucleon are explored with recent results from the AGS experiment E917. Current analyses of stopping, collective flow signals and HBT parameters are presented. Strangeness and anti-baryon production is examined using the yields of anti-lambdas and anti-protons

  20. Studying the potential of antihyperons in nuclei with antiprotons

    International Nuclear Information System (INIS)

    The interaction between an antibaryon and a nucleus may shed light on the short range antibaryon-baryon force in a unique way. However, because of the deep imaginary part of the nuclear potential of antibaryons, the physics of antihyperons in nuclei is hitherto an uncharted territory. Recently it was proposed to use transverse momentum correlations of exclusively produced antihyperon-hyperon pairs in antiproton-nucleus collisions to obtain information on the antihyperon potentials relative to that of the corresponding hyperon. In the present study we use the Giessen Boltzmann-Uehling- Uhlenbeck Transportmodell (GiBUU) to explore the production of exclusive hyperon-antihyperon pairs close to threshold. Unlike the schematic calculation, these GiBBU simulations take e.g. important rescattering effects into account. In case of anti p + 20Ne → anti ΛΛ+X we confirm a significant sensitivity of transverse momentum correlations to the nuclear potential of Λs. We also explore the feasibility of such measurements at the PANDA experiment of the international facility FAIR.

  1. Strange particle production in p+p collisions at Vs=200 GeV

    OpenAIRE

    Y. Bai; Benedosso, F.; Botje, M.A.J.; Castillo, J.; Grebenyuk, O.; Mischke, A.; Peitzmann, T.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands); Russcher, M. J.; Snellings, R. J M; van der Kolk, N.

    2007-01-01

    We present strange particle spectra and yields measured at midrapidity in √s=200 GeV proton-proton (p+p) collisions at the BNL Relativistic Heavy Ion Collider (RHIC). We find that the previously observed universal transverse mass (mT≡√pT2+m2) scaling of hadron production in p+p collisions seems to break down at higher mT and that there is a difference in the shape of the mT spectrum between baryons and mesons. We observe midrapidity antibaryon to baryon ratios near unity for Λ and Ξ baryons a...

  2. Multichannel baryonium and some peculiarities of its decay

    International Nuclear Information System (INIS)

    A new kind of the baryonium which is a result of baryon-antibaryon-channel coupling and has specific decay properties is studied. The system N anti N-Y ant Y (Y=Σ, Λ) is treated as a physical example. It is shown that narrow resonances may exist in this system between N anti N and Y anti Y thresholds. The peculiarities of these resonances are as follows: N anti N is the only distinguished two-particle decay channel, K-meson modes dominate amongst multimeson channels. Experimental ways to search for these resonances are suggested

  3. Study of High Energy Nucleus-Nucleus Interactions Using the $\\Omega^{'}$ Spectrometer Equipped with a Multiparticle High $p_{T}$ Detector

    CERN Multimedia

    2002-01-01

    The experiment is looking for new physics in 200~GeV/c per nucleon sulphur-tungsten collisions in the $\\Omega$' spectrometer. In particular, we are looking for a quark gluon plasma signature in the increase of the production rate of strange and multistrange baryons and antibaryons. In view of the large number of secondaries, we are using a special detector arrangement, called a ``butterfly system'', which has a large acceptance for particles with 2.2~$\\leq$~ $y _{l}ab $ ~$\\leq$~3.2 and $p _{T} $ ~$>$~0.6 ~GeV/c and is insensitive to all the other particles.

  4. Hyperon production in the WA89 experiment at CERN

    International Nuclear Information System (INIS)

    We studied the production of strange baryons and anti-baryons in 345 GeV/c Σ-+Cu, π-+Cu and 260 GeV/c n+Cu interactions. The observation of different excited resonances with identical quark flavor content but different spin structure allows to explore the importance of the constituent diquark structure in the excited hyperons. The xF distributions of Λ - Λ pairs indicate different distribution functions for the two coincident baryons. On the other hand two anti Λ follow identical distribution functions. Momentum conservation during the formation process may represent a significant source for the observed behaviour. (orig.)

  5. Quarks and hadrons

    International Nuclear Information System (INIS)

    This paper reviews the different dynamical stages of a relativistic nuclear collision, from the pre-equilibrium initial stage through a hydrodynamic expansion stage to the particle freeze-out point. Several interesting observables will be discussed and analyzed for their relevance and information content with regard to these various stages. In particular the author touches on antibaryon and φ meson production as a probe for the approach to chemical equilibrium, and on the hadronic transverse momentum spectra as a probe for collective transverse flow in these collisions. Several of these theoretical ideas will be confronted with the recent heavy-ion data from CERN and Brookhaven

  6. Confining Bond Rearrangement in the Random Center Vortex Model

    CERN Document Server

    Altarawneh, Derar; Engelhardt, Michael

    2015-01-01

    We present static meson-meson and baryon--anti-baryon potentials in Z(2) and Z(3) random center vortex models for the infrared sector of Yang-Mills theory, i.e., hypercubic lattice models of random vortex world-surfaces. In particular, we calculate Polyakov loop correlators of two static mesons resp. (anti-)baryons in a center vortex background and observe that their expectation values follow the minimal area law and show bond rearrangement behavior. The static meson-meson and baryon--anti-baryon potentials are compared with theoretical predictions and lattice QCD simulations.

  7. Baryon instability search in large detectors

    International Nuclear Information System (INIS)

    Nucleon decay appears as a consequence of models trying to explain the baryon-antibaryon asymmetry. This has motivated 15 years ago many underground experiments devoted to the search of proton and neutron decay. A very large number of decay channels have been investigated and no evidence has been found yielding lower limits on lifetime which rule out the minimal SU(5) Grand Unified Theory predictions and put severe constraints on more complicated models. Next generation experiments like Super-Kamiokande, which is starting to take data now, ICARUS, whose a 600 ton prototype is under construction, will be sensitive to more complicated models predicting larger lifetimes. (author)

  8. Enhancement of strange and multi-strange baryons in central Pb-Pb interactions at 158 GeV/c per nucleon

    CERN Document Server

    Evans, D; Bakke, H; Beusch, Werner; Bloodworth, Ian J; Caliandro, R; Carrer, N; Di Bari, D; Di Liberto, S; Elia, D; Fanebust, K; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Helstrup, H; Holme, A K; Huss, D; Jacholkowski, A; Jones, G T; Kinson, J B; Knudson, K P; Králik, I; Lenti, V; Lietava, R; Loconsole, R A; Løvhøiden, G; Manzari, V; Mazzoni, M A; Meddi, F; Michalon, A; Michalon-Mentzer, M E; Morando, M; Norman, P I; Pastircák, B; Quercigh, Emanuele; Romano, G; Safarík, K; Sándor, L; Segato, G F; Staroba, P; Thompson, M; Thorsteinsen, T F; Torrieri, G D; Tveter, T S; Urbán, J; Villalobos Baillie, O; Virgili, T; Votruba, M F; Závada, P

    2000-01-01

    Strange and multi-strange baryon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a quark-gluon plasma takes place. The production yields and transverse mass spectra of strange and multi-strange baryons and anti-baryons are presented for lead-lead interactions at 158 GeV/c per nucleon. Yields and transverse mass spectra from proton-lead and proton-beryllium interactions, where no phase transition is expected, are also presented and compared to those from lead-lead interactions. (5 refs).

  9. SO(10) unified theories and cosmology

    International Nuclear Information System (INIS)

    The status of a class of gauge unified models based on the SO(10) group is reviewed. After a pedagogical introduction to SO(10) gauge theories, the main phenomenological implications of these models are discussed. The upper limit on the proton lifetime is obtained, and the prediction for the neutrino masses is compared with the astrophysical and cosmological constraints coming from solar-neutrino data and the dark-matter problem. Possible scenarios for the generation of the baryon-antibaryon asymmetry that is required in the universe by primordial nucleosynthesis are also considered

  10. Study of the production of strange and multi-strange particles in lead-lead interactions at the CERN SPS the NA57 experiment

    CERN Document Server

    Antinori, Federico; Barbera, R; Bloodworth, Ian J; Botje, M; Caliandro, R; Campbell, M; Cantatore, E; Carena, W; Carrer, N; De Haas, A P; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Fanebust, K; Fedorisin, J; Feofilov, G A; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Gulino, M; Helstrup, H; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Klempt, W; Knudson, K; Kocper, B; Kolojvari, A A; Králik, I; Kuijer, P; Lenti, V; Lietava, R; Løvhøiden, G; Lupták, M; Manzari, V; Mazzoni, M A; Martinská, G; Meddi, F; Michalon, A; Michalon-Mentzer, M E; Morando, M; Muigg, D; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Sené, M; Sené, R; Segato, G F; Snoeys, W; Staroba, P; Thompson, M; Tomasicchio, G; Torrieri, G D; Tulina, T A; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Van de Vyvre, P; van Eijndhoven, N; Vannucci, Luigi; Vascotto, Alessandro; Villalobos Baillie, O; Vinogradov, I; Virgili, T; Votruba, M F; Vrláková, J; Závada, P

    2001-01-01

    The NA57 experiment studies the production of strange and multi- strange baryons and antibaryons in ultrarelativistic nucleus-nucleus collisions at the SPS. The main aim of NA57 is to investigate the behaviour of the enhancement of the production of particles with strangeness |s|=1,2,3 in nucleus-nucleus collisions at the variation of the energy and of the centrality of the collision defined, e.g. as the number of participant nucleons. We shall recall the main features of the experimental set-up, and we shall illustrate the collected data samples and the status of their analysis.

  11. Enhancement of strange and multi-strange baryons in central Pb-Pb interactions at 158 GeV/c per nucleon

    International Nuclear Information System (INIS)

    Strange and multi-strange baryon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a Quark-Gluon Plasma takes place. The production yields and transverse mass spectra of strange and multi-strange baryons and anti-baryons are presented for lead-lead interactions at 158 GeV/c per nucleon. Yields and transverse mass spectra from proton-lead and proton-beryllium interactions, where no phase transition is expected, are also presented and compared to those from lead-lead interactions

  12. Hyperon production in lead-lead interactions at 40 and 160 A GeV/c

    International Nuclear Information System (INIS)

    The NA57 experiment has measured strange baryon and antibaryon production in Pb-Pb collisions at 40 A GeV/c and 160 A GeV/c beam momenta. This presentation covers strangeness enhancement and transverse spectra from the 160 A GeV/c data, and energy dependence of the particle yields. Enhancement factors increase with increasing strangeness content of the particle, when production yields from Pb-Pb collisions are compared with those observed in p-Be and p-Pb interactions. The transverse mass spectra have been analysed both with exponential fits and using a transverse flow model. (orig.)

  13. Hyperon production in 40 A GeV/c collisions from the NA57 experiment

    International Nuclear Information System (INIS)

    Enhancements of strange baryon and anti-baryon yields were first observed in Pb-Pb interactions at 160 A GeV/c by WA97. The aim of the NA57 experiment is to investigate how these enhancements behave as a function of energy, and over a broader centrality range than that which was available with WA97. This paper presents a comparison of the hyperon yields in Pb-Pb interactions at 40 A GeV/c and 160 A GeV/c. Preliminary signals for the p-Be data at 40 A GeV/c are also shown

  14. Strange baryon production from the NA57 experiment at the CERN SPS

    CERN Document Server

    Antinori, Federico; Barbera, R; Belogianni, A; Bhasin, A; Bloodworth, Ian J; Bruno, G; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; Dainese, A; De Haas, A P; De Rijke, P C; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Fedorisin, J; Feofilov, G A; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Helstrup, H; Henriquez, M; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratiev, V; Krilik, I; Kravcakova, A; Kuijer, P G; Lenti, V; Lietava, R; Løvhøiden, G; Lupták, M; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Muigg, D; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Spyropoulou-Stassinaki, M; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Vyvre, P V; van Eijndhoven, N; Van Hunen, J J; Vascotto, Alessandro; Vik, T; Villalobos Baillie, O; Vinogradov, L I; Virgili, T; Votruba, M F; Vrláková, J; Závada, P

    2002-01-01

    The production of strange baryons and antibaryons in Pb+Pb and p+Be collisions has been studied by the NA57 experiment at the CERN SPS, extending down the centrality range covered by the previous WA97 experiment, and collecting data at two different energies. The enhanced production of such particles in central Pb+Pb collisions with respect to p+Be has been experimentally confirmed. This paper discusses results on Xi and Lambda hyperon production obtained at 40 and 158 AGeV/c. (6 refs).

  15. Results on 40 A GeV/c Pb-Pb collisions from the NA57 experiment

    International Nuclear Information System (INIS)

    The NA57 experiment has been designed to study the onset of the strange baryon and antibaryon enhancements in Pb-Pb with respect to p-Be collisions, first observed by WA97 at 160 A GeV/c. NA57 has extended the WA97 measurements to investigate the evolution of strangeness enhancement over a wider centrality range and as a function of the beam energy. Results on hyperon production in central Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same centrality range

  16. Results on 40 A GeV/c Pb-Pb collisions from the NA57 experiment

    CERN Document Server

    Elia, D; Badalà, A; Barbera, R; Belogianni, A; Bhasin, A; Bloodworth, Ian J; Bruno, G; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; Dainese, A; De Haas, A P; De Rijke, P C; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Fedorisin, J; Feofilov, G A; Fini, R A; Ganoti, P; Chidini, B; Grella, G; Helstrup, H; Henriquez, M; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratiev, V; Králik, I; Kravcakova, A; Kuijer, P G; Lenti, V; Lietava, R; Løvhøiden, G; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Spyropoulou-Stassinaki, M; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Van de Vyvre, P; van Eijndhoven, N; Van Hunen, J J; Vascotto, Alessandro; Vik, T; Villalobos Baillie, O; Vinogradov, L I; Virgili, T; Votruba, M F; Vrláková, J; Závada, P

    2003-01-01

    The NA57 experiment has been designed to study the onset of the strange baryon and antibaryon enhancements in Pb-Pb with respect to p-Be collisions, first observed by WA97 at 160 A GeV/c. NA57 has extended the WA97 measurements to investigate the evolution of strangeness enhancement over a wider centrality range and as a function of the beam energy. Results on hyperon production in central Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same centrality range. (8 refs).

  17. Midrapidity hyperon production in pp and pA collisions from low to LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Arakelyan, G.H. [Yerevan Physics Institute, A.Alikhanyan National Scientific Laboratory, Yerevan (Armenia); Merino, C. [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas, Facultade de Fisica y Instituto Galego de Fisica de Altas Enerxias (IGFAE), Galiza (Spain); Shabelski, Yu.M. [NCR Kurchatov Institute, Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation)

    2016-01-15

    The experimental data on p, Λ, Ξ{sup -}, Ω{sup -} -baryons and the corresponding antibaryons spectra obtained by different collaborations are compared with the results of the calculations performed into the frame of the quark-gluon string model. The contribution of string junction diffusion and the inelastic screening corrections are accounted for in the theoretical calculations. The predictions of the quark-gluon string model both for pp and pA collisions are extended up to the LHC energies. (orig.)

  18. New facts about muon production in Extended Air Shower simulations

    CERN Document Server

    Pierog, T

    2006-01-01

    Whereas air shower simulations are very valuable tools for interpreting cosmic ray data, there is a long standing problem: is seems to be impossible to accommodate at the same time the longitudinal development of air showers and the number of muons measured at ground. Using a new hadronic interaction model (EPOS) in air shower simulations produces considerably more muons, in agreement with results from the HiRes-MIA experiment. We find that this is mainly due to a better description of baryon-antibaryon production in hadronic interactions. This is a new aspect of air shower physics which has never been considered so far.

  19. `Internal` B-meson decays. DIS and HQET approach

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Martirosyan, K.A. [Gosudarstvennyj Komitet po Ispol`zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Teoreticheskoj i Ehksperimental`noj Fiziki

    1994-12-31

    Inclusive B-meson decays, in particular of `internal` types (into heavy mesons and baryon pairs),are considered using Deep Inelastic Scattering (DIS) and Heavy Quark Effective Theory (HQET) type approaches. Quite large 12% contribution of these nonleptonic decays (7% only of baryon pairs resulting from diquark production) has been found. This leads to a considerable reduction of the semileptonic decay ratio down to its experimental value, 9%. It explains simultaneously experimental data on the large fraction 7% of B-decays into baryon-antibaryon pairs. The general picture of distributions of b decays branchings of all main types types is presented. (author). 16 refs., 11 figs.

  20. First Observation of the Decay D_s^+ to proton anti-neutron

    CERN Document Server

    Athar, S B; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; López, A; Méndez, H; Ramírez, J; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Naik, P; Rademacker, J; Asner, D M; Edwards, K W; Reed, J; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hunt, J M; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Ledoux, J; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T

    2008-01-01

    Using e^+e^- -> D_s^*+ D_s^- data collected near the peak D_s production energy, E_cm=4170 MeV, with the CLEO-c detector, we present the first observation of the decay D_s^+ -> proton anti-neutron. We measure a branching fraction B(D_s^+ -> p anti-n = (1.30 +- 0.36 +0.12 -0.16) x 10^-3. This is the first observation of a charmed meson decaying into a baryon-antibaryon final state.

  1. Random-walk baryogenesis via primordial black holes

    OpenAIRE

    Semiz, İbrahim

    2016-01-01

    Gravitation violates baryon number $B$: A star has a huge amount of it, while a black hole forming from the star has none. Consider primordial black holes before the hadronic annihiliation in the early universe, encountering and absorbing baryons and antibaryons: Each such absorption changes $B$ of the universe by one unit, up or down. But the absorption events are $uncorrelated$ $and$ $random$, hence they amount to a random walk in $B$-space, leading to the expectation of a net $|B|$ at the ...

  2. High energy particle physics at Purdue. Annual progress report, March 1981-1982

    International Nuclear Information System (INIS)

    Progress is reported in these areas: study of electron positron annihilation using the High Resolution Spectrometer at PEP; experimental study of proton decay; a study of rare processes in meson spectroscopy utilizing the SLAC Hybrid Bubble Chamber System; theory of fundamental problems of gravitational, electromagnetic, weak, and strong interactions; experimental study of chi production by hadrons; p-nucleus interactions; development of the Collider Detector at Fermilab; anitneutrino physics and low energy neutrino physics; and the study of the observed hadrons as the relativistic bound states of baryons and antibaryons

  3. No Sommerfeld resummation factor in e{sup +}e{sup -}{yields}p anti p ?

    Energy Technology Data Exchange (ETDEWEB)

    Baldini Ferroli, R. [Museo Storico della Fisica e Centro Studi e Ricerche ' ' E. Fermi' ' , Rome (Italy); Laboratori Nazionali di Frascati, INFN, Frascati (Italy); Pacetti, S. [Universita di Perugia, Dipartimento di Fisica, Perugia (Italy); INFN, Perugia (Italy); Zallo, A. [Laboratori Nazionali di Frascati, INFN, Frascati (Italy)

    2012-03-15

    The Sommerfeld rescattering formula is compared to the e{sup +}e{sup -}{yields}p anti p BABAR data at threshold and above. While there is the expected Coulomb enhancement at threshold, two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e. vertical stroke G {sup p} (4M{sub p}{sup 2}) vertical stroke = 1, as a pointlike fermion, and, moreover, data show that the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -}{yields} baryon-antibaryon cross-sections show similar behavior near threshold. (orig.)

  4. Baryon Form Factors at Threshold

    Energy Technology Data Exchange (ETDEWEB)

    Baldini Ferroli, Rinaldo [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Rome (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pacetti, Simone [INFN and Dipartimento di Fisica, Universita di Perugia, Perugia (Italy)

    2012-04-15

    An extensive study of the e{sup +}e{sup -}{yields}pp{sup Macron }BABAR cross section data is presented. Two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e.: |G{sup p}(4M{sub p}{sup 2})|=1, as a pointlike fermion, and the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -} {yields} baryon-antibaryon cross sections show a similar behavior near threshold.

  5. Rate equation network for baryon production in high energy nuclear collisions

    International Nuclear Information System (INIS)

    We develop and solve a network of rate equations for the production of baryons and antibaryons in high energy nuclear collisions. We include all members of the baryon octet and decuplet and allow for transformations among them. This network is solved during a relativistic 2+1 hydrodynamical expansion of the of the hot matter created in the collision. As an application we compare to the number of protons, Λ's, negative cascades, and Ω baryons measured at midrapidity in central collisions of gold nuclei at 65 GeV per nucleon at the Relativistic Heavy Ion Collider (RHIC)

  6. decays to baryons

    Indian Academy of Sciences (India)

    Torsten Leddig

    2012-11-01

    From inclusive measurements, it is known that about 7% of all mesons decay into final states with baryons. In these decays, some striking features become visible compared to mesonic decays. The largest branching fractions come with quite moderate multiplicities of 3–4 hadrons. We note that two-body decays to baryons are suppressed relative to three- and four-body decays. In most of these analyses, the invariant baryon–antibaryon mass shows an enhancement near the threshold. We propose a phenomenological interpretation of this quite common feature of hadronization to baryons.

  7. Flavor production in PB(160 AGEV) on PB collisions: Effect of color ropes and hadronic rescattering

    International Nuclear Information System (INIS)

    Collective interactions in the preequilibrium quark matter and hadronic resonance gas stage of ultrarelativistic nucleus-nucleus collisions are studied in the framework fo the transport theoretical approach RQMD. The paper reviews string fusion into color ropes and hadronic rescattering which serve as models for these interactions. Hadron production in central Pb(160 AGeV) on Pb collisions has been calculated. The changes of the final flavor composition are more pronounced than in previous RQMD studies of light ion induced reactions at 200 AGeV. The ratio of created quark pairs s anti s/(u anti u+d anti d) is enhanced by a factor of 2.4 in comparison to pp results. Color rope formation increases the initially produced antibaryons to 3 times the value in the 'NN mode', but only one quarter of the produced antibaryons survives because of subsequent strong absorption. The differences in the final particle composition for Pb on Pb collisions compared to S induced reactions are attributed to the hadronic resonance gas stage which is baryon-richer and lasts longer. (orig.)

  8. Extracting $p\\Lambda$ scattering lengths from heavy ion collisions

    CERN Document Server

    Shapoval, V M; Lednicky, R; Sinyukov, Yu M

    2015-01-01

    The $p-\\Lambda \\oplus \\bar{p}-\\bar{\\Lambda}$ and $\\bar{p}-\\Lambda \\oplus p-\\bar{\\Lambda}$ correlation functions for 10% most central Au+Au collisions at top RHIC energy $\\sqrt{s_{NN}}=200$ GeV are modeled with Lednicky and Lyuboshitz analytical formula using the source radii extracted from the hydrokinetic model (HKM) simulations. For the baryon-antibaryon case the corresponding spin-averaged strong interaction scattering length is obtained by fitting the STAR correlation function. In contrast to the experimental results, where extracted $p\\bar{\\Lambda}$ source radius value was found $\\sim 2$ times smaller than the corresponding $p\\Lambda$ one, the calculations in HKM show both $p\\Lambda$ and $p\\bar{\\Lambda}$ effective source radii to be quite close, as expected from theoretical considerations. To obtain the satisfactory fit to the measured baryon-antibaryon correlation function at this large source radius value, the modified analytical approximation to the correlation function, effectively accounting for the...

  9. Antimatter and Matter Production in Heavy Ion Collisions at CERN (The NEWMASS Experiment NA52)

    CERN Document Server

    Ambrosini, G; Baglin, C; Beck, H P; Borer, K; Bussière, A; Elsener, K; Gorodetzky, P; Guillaud, J P; Hess, P O; Kabana, S; Klingenberg, R; Lehmann, G; Lindén, T; Lohmann, K D; Mommsen, R K; Moser, U; Pretzl, Klaus P; Schacher, J; Spiwoks, R; Stoffel, F; Tuominiemi, Jorma; Weber, M; Gorodetzky, Ph.

    2000-01-01

    Besides the dedicated search for strangelets NA52 measures light (anti)particle and (anti)nuclei production over a wide range of rapidity. Compared to previous runs the statistics has been increased in the 1998 run by more than one order of magnitude for negatively charged objects at different spectrometer rigidities. Together with previous data taking at a rigidity of -20 GeV/c we obtained 10^6 antiprotons 10^3 antideuterons and two antihelium3 without centrality requirements. We measured nuclei and antinuclei (p,d,antiprotons, antideuterons) near midrapidity covering an impact parameter range of b=2-12 fm. Our results strongly indicate that nuclei and antinuclei are mainly produced via the coalescence mechanism. However the centrality dependence of the antibaryon to baryon ratios show that antibaryons are diminished due to annihilation and breakup reactions in the hadron dense environment. The volume of the particle source extracted from coalescence models agrees with results from pion interferometry for an...

  10. Baryogenesis via Hawking-like Radiation in the FRW Space-time

    CERN Document Server

    Modak, Sujoy K

    2014-01-01

    We present a phenomenological model for baryogenesis based on particle creation in the Friedman-Robertson-Walker (FRW) space-time. This study is a continuation of our proposal that Hawking-like radiation in FRW space-time explains several physical aspects of the early Universe including inflation. In this model we study a coupling between the FRW space-time, in the form of the derivative of the Ricci scalar, and the $B-L$ current, $J^{\\mu} _{B-L}$, which leads to a different chemical potential between baryons and anti-baryons resulting in an excess of baryons over anti-baryons with the right order of magnitude. In this model the generation of baryon asymmetry, in principle, occurs over the entire history of the Universe starting from the beginning of the radiation phase. However, in practice, almost the entire contribution to the baryon asymmetry only comes from the very beginning of the Universe and is negligible thereafter. There is a free parameter in our model which can be interpreted as defining the boun...

  11. Multi-strange baryon production in pp collisions at √(s)=7 TeV with ALICE

    International Nuclear Information System (INIS)

    A measurement of the multi-strange Ξ- and Ω- baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton-proton collisions at a centre-of-mass energy of 7 TeV. The transverse momentum (pT) distributions were studied at mid-rapidity (|y|T- and Ξ¯+ baryons, and in the range of 0.8T- and Ω¯+. Baryons and antibaryons were measured as separate particles and we find that the baryon to antibaryon ratio of both particle species is consistent with unity over the entire range of the measurement. The statistical precision of the current data has allowed us to measure a difference between the mean pT of Ξ- (Ξ¯+) and Ω- (Ω¯+). Particle yields, mean pT, and the spectra in the intermediate pT range are not well described by the PYTHIA Perugia 2011 tune Monte Carlo event generator, which has been tuned to reproduce the early LHC data. The discrepancy is largest for Ω-(Ω¯+). This PYTHIA tune approaches the pT spectra of Ξ- and Ξ¯+ baryons below pT- and Ξ¯+ spectra above pT>6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω-+Ω¯+)/(Ξ-+Ξ¯+) as a function of transverse mass.

  12. Study of B-Meson Decays to Final States with a Single Charm Baryon

    Energy Technology Data Exchange (ETDEWEB)

    Majewski, Stephanie A. [Stanford Univ., CA (United States)

    2007-08-01

    A study of B-meson decays to final states with a single charm baryon is presented based on data recorded by the BABAR detector at the Stanford Linear Accelerator Center. Although the B meson is the lightest bottom-flavored meson, it is heavy enough to decay to a baryon made of three quarks and an antibaryon made of three antiquarks. By studying the baryonic weak decays of the B meson, we can investigate baryon production mechanisms in heavy meson decays. In particular, we measure the rates of the decays B- → Λ+c$\\bar{p}$π- and $\\bar{B}$0 → Λ+c$\\bar{p}$. Comparing these rates, we confirm an observed trend in baryonic B decays that the decay with the lower energy release, B- → Λ+c$\\bar{p}$π-, is favored over $\\bar{B}$0 → Λ+c$\\bar{p}$. The dynamics of the baryon-antibaryon+c$\\bar{p}$) system in the three-body decay also provide insight into baryon-antibaryon production mechanisms. The B- → Λ+c$\\bar{p}$π- system is a laboratory for searches for excited #c baryon states; we observe the resonant decays B- → Σc(2455) 0$\\bar{p}$ and B- → Σc(2800) 0$\\bar{p}$. This is the first observation of the decay B- → Σc(2800) 0$\\bar{p}$; however, the mass of the observed #c(2800)0 state is inconsistent with previous measurements. Finally, we examine the angular distribution of the B- → Σc(2455) 0$\\bar{p}$ decays and measure the spin of the B- → Σc(2455) 0$\\bar{p}$ baryon to be J = 1/2, as predicted by the quark model.

  13. Fast Equilibration of Hadrons in an Expanding Fireball

    CERN Document Server

    Noronha-Hostler, J; Shovkovy, I A

    2007-01-01

    Due to long chemical equilibration times within standard hadronic reactions during the hadron gas phase in relativistic heavy ion collisions it has been suggested that the hadrons are "born" into equilibrium after the quark gluon plasma phase. Here we develop a dynamical scheme in which possible Hagedorn states contribute to fast chemical equilibration times of baryon anti-baryon pairs (as well as kaon anti-kaon pairs) inside a hadron gas and just below the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. Applying a Bjorken picture to the expanding fireball, the kaons and baryons as well as the bath of pions and Hagedorn resonances can indeed quickly chemically equilibrate for both an initial overpopulation or underpopulation of Hagedorn resonances. Moreover, a comparison of our results to $(B+\\bar{B})/\\pi^{+}$ and $K/\\pi^{+}$ ratios at RHIC, indeed, shows a close match.

  14. Antiproton-proton Annihilation Into Two Mesons: The Role Of Relativistic Distortion

    CERN Document Server

    El-Bennich, B O

    2004-01-01

    The more than a decade old data on differential cross sections and analyzing powers in antiproton-proton annihilation into two pions (or two kaons), measured at the Low Energy Antiproton Ring (LEAR) of CERN, have stimulated several theoretical investigations. A characteristic feature of the data are the large variations of the scattering observables as a function of the scattering angle and of the laboratory energy already below 100 MeV. Amplitude analyzes reproduce the data with few partial waves (J ≤ 4) and one concludes that the annihilation process is very short- ranged and of the order of the nucleon size. Nonetheless, early models, using either baryonic or quark degrees of freedom, give rise to an even shorter antibaryon-baryon interaction failing to produce substantial higher (J ≥ 2) partial wave amplitudes and consequently to adequately describe the LEAR data. In this thesis, we systematically consider improvements within the framework of quark-line diagrams. We first derive various quar...

  15. Gordon Research Conference on Particle Physics : Prospects of Particle Physics at the 13TeV Large Hadron Collider

    CERN Document Server

    2015-01-01

    There are compelling reasons for us to believe that the Standard Model (SM) of particle physics is not complete. Theoretically, the mass of the SM Higgs boson receives quadratically divergent corrections at the quantum level and hence is not stable. Stabilizing the Higgs mass requires the existence of beyond-the-SM (BSM) physics. Cosmologically, observations reveal that the total mass of the Universe today is largely composed of dark matter (DM). Our knowledge on the DM properties (e.g., its species, mass, interaction) however is very poor. In addition we do not understand why there is more baryonic matter than anti-baryonic matter in the Universe. While both cosmic mysteries involve physics of the large scale, solving them heavily depends on physics of the small scale and requires the BSM physics as well.

  16. A simple powerful description of meson and baryon flavor formation in e+e- annihilations

    International Nuclear Information System (INIS)

    A simple ansatz, using a fragmentation function which is derived from area law and relativistic string considerations as a production density of hadrons, describes a broad range of e+e- annihilation data without need for the many quark level parameters. This approach inherently provides a semi - absolute baryon-to-meson normalization structure. The model emphasizes intermediate meson (popcorn) production between baryon and antibaryon as a new degree of freedom for baryon production. This ansatz is implemented using a modified version of the Lund JETSET Monte Carlo program, utilizing its parton shower treatment and hadron decay tables. With only ∼5 significant parameters and choices, quite good agreement has been found with a wide range of data at 10, 29 and 91 GeV. (author) 5 figs.; 1 tab

  17. A new high sensitivity search for neutron-antineutron oscillations at the ESS

    CERN Document Server

    Milstead, David

    2015-01-01

    A sensitive search for neutron-antineutron oscillations can provide a unique probe of some of the central questions in particle physics and cosmology: the energy scale and mechanism for baryon number violation, the origin of the baryon-antibaryon asymmetry of the universe, and the mechanism for neutrino mass generation. A remarkable opportunity has emerged to search for such oscillations with the construction of the European Spallation Source (ESS). A collaboration has been formed which has proposed a search at the ESS, which would provide a sensitivity to the oscillation probability which is three orders of magnitude greater than that achieved at an ILL experiment at which the present best limit on free neutron-antineutron oscillations was obtained.

  18. Study of the A-dependence of inclusive p,anti p,Λ and anti Λ production in πsup(+-) -nucleus interactions at 30 GeV/c

    International Nuclear Information System (INIS)

    We present the first results on the propduction of fast (p>10 GeV/c) p, anti p, Λ and anti Λ from PIsup(+-) hydrogen and nucleus interactions at 30 GeV/c using the CERN Ω' spectrometer. We have used five nuclear targets (C, Al, Cu, Sn, Pb) to study the A-dependence of the inclusive particle distributions in the region 0.3< xsub(F)<0.6. The high statistical level of our experiment allows us to demonstrate the different A-behaviour of baryon and antibaryon inclusive reactions. We relate this difference to the final state interaction inside a nucleus using the formation-zone model. (orig.)

  19. Selected results on J/psi hadronic decays from DM2 and Mark III

    International Nuclear Information System (INIS)

    Results from the high statistics experiments Mark III and DM2 on J/psi hadronic decays are reviewed. Special interest is given to SU3 violating decays into two pseudoscalars and baryon-antibaryon, especially the first observation of J/psi → K0sub(S)K0sub(L). The complete measurement of the vector + pseudoscalar modes allows a new determination of the eta and eta' mixing parameters, indicating the presence of a new component in the eta' wave function. The iota(1440) and theta(1700) gluonium candidates have been searched for in hadronic decays, and the Mark III experiment observes a signal in J/psi → ω iota (or ωE)

  20. Energy dependence of hyperon production in nucleus-nucleus collisions at SPS

    CERN Document Server

    Antinori, F; Badalà, A; Barbera, R; Belogianni, A; Bhasin, A; Bloodworth, Ian J; Bombara, M; Bruno, G; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; Dainese, A; De Haas, A P; De Rijke, P C; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Feofilov, G A; Fini, R A; Ganoti, P; Ghidini, B; Grella, G; Helstrup, H; Hetland, K F; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratiev, V; Králik, I; Kravcakova, A; Kuijer, P; Lenti, V; Lietava, R; Løvhøiden, G; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Spyropoulou-Stassinaki, M; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Van de Vyvre, P; van Eijndhoven, N; Van Hunen, J J; Vascotto, Alessandro; Vik, T; Villalobos Baillie, O; Vinogradov, L I; Virgili, T; Votruba, M F; Vrláková, J; Závada, P

    2004-01-01

    A measurement of strange baryon and antibaryon production in Pb-Pb collisions has been carried out by the NA57 experiment at the CERN SPS, with 40 and 158 A GeV/c beam momentum. Results on $\\Lambda$, $\\Xi$ and $\\Omega$ hyperon yields at mid-rapidity in the most central 53% of Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same collision centrality range. The $\\Lambda$ and $\\Xi^-$ yields per unit rapidity stay roughly constant while those of $\\Omega^-$, $\\bar\\Lambda$, $\\bar\\Xi^+$ and $\\bar\\Omega^+$ increase when going to the higher SPS energy. Hyperon yields at the SPS are compared with those from the STAR experiment in $\\sqrt{s_{NN}}$ = 130 GeV Au-Au collisions at RHIC.

  1. Cosmological bang as a consequence of a sharp breakdown of quantum statistics in the nuclear matter

    International Nuclear Information System (INIS)

    A heuristic hypothesis about dominating of Bose-statistics in the early Universe, at the transition from the Radiation Era to the Matter Era is suggested. The possibility of Bose-Einstein condensate of the matter, consisted of baryon-antibaryon pairs is considered. Due to this phenomenon, the enormous mass may accumulate within the cosmic scales. At the several threshold value of the density these structural bosons decay into composing fermions; as a result the sharp breakdown of symmetry of the particles' wave function occurs and the Bose-Einstein statistics spasmodically transforms into Fermi-Dirac one. A large-scale phase transition occurs due to this process, conducted with enormous pressure jump, which may become apparent as a Cosmological Bang at the beginning stage of Matter Era

  2. Random-walk baryogenesis via primordial black holes

    CERN Document Server

    Semiz, İbrahim

    2016-01-01

    Gravitation violates baryon number $B$: A star has a huge amount of it, while a black hole forming from the star has none. Consider primordial black holes before the hadronic annihiliation in the early universe, encountering and absorbing baryons and antibaryons: Each such absorption changes $B$ of the universe by one unit, up or down. But the absorption events are $uncorrelated$ $and$ $random$, hence they amount to a random walk in $B$-space, leading to the expectation of a net $|B|$ at the end. While the scale of this effect is most uncertain, it must exist. We explore some ramifications, including the change of net $|B|$ with expansion, connection with universe topology, and possible observational signatures.

  3. The chicken or the egg; or Who ordered the chiral phase transition?

    CERN Document Server

    Kogan, I I; Tekin, B; Kogan, Ian I.; Kovner, Alex; Tekin, Bayram

    2001-01-01

    We draw an analogy between the deconfining transition in the 2+1 dimensional Georgi-Glashow model and the chiral phase transition in 3+1 dimensional QCD. Based on the detailed analysis of the former (hep-th/0010201) we suggest that the chiral symmetry restoration in QCD at high temperature is driven by the thermal ensemble of baryons and antibaryons. The chiral symmetry is restored when roughly half of the volume is occupied by the baryons. Surprisingly enough, even though baryons are rather heavy, a crude estimate for the critical temperature gives $T_c=180$ Mev. In this scenario the binding of the instantons is not the cause but rather a consequence of the chiral symmetry restoration.

  4. Studies of quark and diquark fragmentation into identified hadrons in deep inelastic muon-proton scattering

    International Nuclear Information System (INIS)

    Data on identified hadrons produced in deep inelastic muon-proton scattering are presented. Results on the normalized Xsub(F) distributions of charged pions, kaons, protons and antiprotons are given. The negative Xsub(F) region below Xsub(F) 2 dependence. Lambdas show a similar fragmentation behaviour to protons. Significant production of antibaryons is observed in the current fragmentation region (Xsub(F) > 0). The relative fraction of kaons and protons is found to increase in the forward direction. The mean multiplicities of identified hadrons are observed to rise logarithmically with W2, the rise of the pion multiplicity being much faster than that for kaons and protons. The 2> in the central Xsub(F) region is larger for charged kaons and protons than for pions. The measurements are compared to the predictions of the Lund string model. (orig.)

  5. Observation and study of bottom-meson decays to a charm meson, a proton-antiproton pair, and pions

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Tae Min [Univ. of California, Santa Barbara, CA (United States)

    2010-04-27

    Bottom-meson decays with baryons show two unusual features—the branching fractions are enhanced for multibody decays and the baryon-antibaryon subsystem recoils against the other decay products—and their reasons are not yet well understood. Moreover, measurements using explicit reconstruction techniques constitute only about 1% out of about 8% of such decays. This Dissertation reports the study of ten bottom-meson decays (labeled 0– 9) to a proton-antiproton pair, a charm meson, and a system of up to two pions, using the BABAR Experiment’s 455×106 BB pairs produced with the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center.

  6. Baryon production at PEP

    International Nuclear Information System (INIS)

    Measurements of inclusive Λ + anti Λ production for 1.0 less than or equal to p less than or equal to 10.0 GeV/c and p + anti p production for 0.4 less than or equal to p less than or equal to 2.0 GeV/c show significant baryon production in e+e- annihilation at E/sub cm/ = 29 GeV. Λ + anti Λ production represents 0.2 Λ's or anti Λ's per PEP event while the observed p + anti p production implies all baryon-antibaryon pair production is occurring at least as often as 0.6 per event, depending on the yet to be measured p + anti p production at high momentum. Comparisons are made with the first theoretical attempts to account for baryon production at these energies

  7. Quantum Vacuum in Hot Nuclear Matter A Nonperturbative Treatment

    CERN Document Server

    Mishra, A K; Greiner, W; Mishra, Amruta

    2001-01-01

    We derive the equation of state for hot nuclear matter using Walecka model in a nonperturbative formalism. We include here the vacuum polarisation effects arising from the nucleon and scalar mesons through a realignment of the vacuum. A ground state structure with baryon-antibaryon condensates yields the results obtained through the relativistic Hartree approximation (RHA) of summing baryonic tadpole diagrams. Generalization of such a state to include the quantum effects for the scalar meson fields through the $\\sigma$-meson condensates amounts to summing over a class of multiloop diagrams. The techniques of thermofield dynamics (TFD) method are used for the finite temperature and finite density calculations. The in-medium nucleon and sigma meson masses are also calculated in a self consistent manner. We examine the liquid-gas phase transition at low temperatures ($\\approx$ 20 MeV), as well as apply the formalism to high temperatures to examine for a possible chiral symmetry restoration phase transition.

  8. Characterization of a solid deuterium converter for ultra-cold neutrons (UCN) in the framework of the Mini-D{sub 2} project at the FRM-II reactor in Munich

    Energy Technology Data Exchange (ETDEWEB)

    Tortorella, D.

    2007-02-07

    Spontaneous breaking of fundamental symmetries is an attractive topic in modern particles physic. Understanding qualitative and quantitative the parameters involved in these kind of processes could help to explain the unbalanced presence in the universe of matter (baryons) with respect to antimatter (anti-baryons). Due to their intrinsic properties, ultra cold neutrons (UCN) are excellent candidates in experiments measuring with high level of accuracy parameters like the electric dipole moment (EDM), the axial-vector coupling constant (g{sub A}), the neutron lifetime ({tau}{sub n}) or in search of quantum effect of gravity. In this work are presented several contributions in the framework of the Mini-D2 project, an innovative strong UCN source under construction at the FRM-II reactor in Munich. An important component of this facility, the solid deuterium UCN converter, is one subject of the thesis. (orig.)

  9. Analytic treatment of a linear electric field frequency shift induced in confined gases by a magnetic field gradient: Implications for neutron electric dipole moment experiments

    CERN Document Server

    Lamoreaux, S K

    2004-01-01

    The search for particle electric dipole moments (edm) is one of the best places to look for physics beyond the standard model because the size of time reversal violation predicted by the standard model is incompatible with present ideas concerning the creation of the Baryon-Antibaryon asymmetry. As the sensitivity of these edm searches increases more subtle systematic effects become important. We develop a general analytical approach to describe a systematic effect recently observed in an electric dipole moment experiment using stored particles \\cite{JMP}. Our approach is based on the relationship between the systematic frequency shift and the velocity autocorrelation function of the resonating particles. Our results, when applied to well-known limiting forms of the correlation function, are in good agreement with both the limiting cases studied in recent work that employed a numerical/heuristic analysis. Our general approach explains some of the surprising results observed in that work and clarifies several ...

  10. Constituent counting rule for exclusive production of heavy quarkoniumlike exotic resonance and a light hadron

    CERN Document Server

    Voloshin, M B

    2016-01-01

    The exclusive processes are considered, where a point-like source of heavy quark-antiquark pairs $Q \\bar Q$, e.g. their electromagnetic current, produces a pair consisting of a heavy quarkoniumlike exotic meson (tetraquark) or baryon (pentaquark) and a light meson or an antibaryon. For a sufficiently large mass of the heavy quark $m_Q$ there is a range of the energy $E$ above the $Q \\bar Q$ threshold, where $E \\ll m_Q$ and still the energy is large compared to the strong interaction scale, $E \\gg \\Lambda_{QCD}$. It is shown that in this energy range, where the heavy quarks are nonrelelativistic, a specific `intermediate asymptotic' behavior sets in determined by the number $n$ of the pairs of constituent quarks, with the rate scaling as $E^{1-n}$.

  11. Strangeness production and hypernucleus formation in antiproton induced reactions

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Formation mechanism of fragments with strangeness in collisions of antiprotons on nuclei has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport approach combined with a statistical model (GEMINI) for describing the decays of excited fragments. Production of strange particles in the antiproton induced nuclear reactions is modeled within the LQMD model, in which all possible reaction channels such as elastic scattering, annihilation, charge exchange and inelastic scattering in antibaryon-baryon, baryon-baryon and meson-baryon collisions have been included. A coalescence approach is developed for constructing hyperfragments in phase space after de-excitation of nucleonic fragments. The combined approach could describe the production of fragments in low-energy antiproton induced reactions. Hyperfragments are formed within the narrower rapidities and lower kinetic energies. It has advantage to produce heavier hyperfragments and hypernuclides with strangeness s=-2 (double-$\\Lambda$ fra...

  12. Touch BASE

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In a recent Nature article (see here), the BASE collaboration reported the most precise comparison of the charge-to-mass ratio of the proton to its antimatter equivalent, the antiproton. This result is just the beginning and many more challenges lie ahead.   CERN's AD Hall, where the BASE experiment is set-up. The Baryon Antibaryon Symmetry Experiment (BASE) was approved in June 2013 and was ready to take data in August 2014. During these 14 months, the BASE collaboration worked hard to set up its four cryogenic Penning traps, which are the heart of the whole experiment. As their name indicates, these magnetic devices are used to trap antiparticles – antiprotons coming from the Antiproton Decelerator – and particles of matter – negative hydrogen ions produced in the system by interaction with a degrader that slows the antiprotons down, allowing scientists to perform their measurements. “We had very little time to set up the wh...

  13. Characterization of a solid deuterium converter for ultra-cold neutrons (UCN) in the framework of the Mini-D2 project at the FRM-II reactor in Munich

    International Nuclear Information System (INIS)

    Spontaneous breaking of fundamental symmetries is an attractive topic in modern particles physic. Understanding qualitative and quantitative the parameters involved in these kind of processes could help to explain the unbalanced presence in the universe of matter (baryons) with respect to antimatter (anti-baryons). Due to their intrinsic properties, ultra cold neutrons (UCN) are excellent candidates in experiments measuring with high level of accuracy parameters like the electric dipole moment (EDM), the axial-vector coupling constant (gA), the neutron lifetime (τn) or in search of quantum effect of gravity. In this work are presented several contributions in the framework of the Mini-D2 project, an innovative strong UCN source under construction at the FRM-II reactor in Munich. An important component of this facility, the solid deuterium UCN converter, is one subject of the thesis. (orig.)

  14. DCC Dynamics in (2+1)D-O(3) model

    CERN Document Server

    Holzwarth, G

    2001-01-01

    The dynamics of symmetry-breaking after a quench is numerically simulated on a lattice for the (2+1)-dimensional O(3) model. In addition to the standard sigma-model with temperature-dependent Phi^4-potential the energy functional includes a four-derivative current-current coupling to stabilize the size of the emerging extended topological textures. The total winding number can be conserved by constraint. As a model for the chiral phase transition during the cooling phase after a hadronic collision this allows to investigate the interference of 'baryon-antibaryon' production with the developing disoriented aligned domains. The growth of angular correlations, condensate, average orientation is studied in dependence of texture size, quench rate, symmetry breaking. The classical dissipative dynamics determines the rate of energy emitted from the relaxing source for each component of the 3-vector field which provides a possible signature for domains of Disoriented Chiral Condensate. We find that the 'pions' are em...

  15. Baryon production from embedded metastable strings

    CERN Document Server

    Karouby, Johanna

    2013-01-01

    We quantify the baryon anti-baryon production generated by a metastable cosmic string, similar to the embedded pion string. More precisely, we study skyrmion production mediated by instantons generated by a pion-like metastable string in contact with a thermal bath, and interpret these Skyrmions as baryons. As shown in a previous work, the core of such a metastable string can melt due to quantum tunneling in the charged field direction. The specific configuration of our string containing 4 scalar fields out of equilibrium in contact with a thermal bath is shown to yield skyrmion production with partial or integer winding number. In this work, we describe and quantify this skyrmion production per unit length of the string. We also evaluate the skyrmion-anti skyrmions production by a dense string network by invoking similarity with the Skyrmion production in a phase transition.

  16. On Productions of Net-baryons in Central Au-Au Collisions at RHIC Energies

    CERN Document Server

    Chen, Ya-Hui; Liu, Fu-Hu

    2015-01-01

    The transverse momentum and rapidity distributions of net-baryons (baryons minus anti-baryons) produced in central gold-gold (Au-Au) collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D) spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyzes of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

  17. Results on the production of baryons wiht vertical stroke Svertical stroke = 1, 2, 3 and strange mesons in S-W collisions at 200 GeV/c per nucleon

    International Nuclear Information System (INIS)

    We report results on the production of strange baryons/antibaryons with 1, 2, and 3 units of strangeness (Λ, Ξ and Ω) and mesons (K0s, K+ and K-) in WA85 experiment at the CERN SPS. This experiment was designed to study the production of strange particles in central SW collisions at 200 GeV/c per nucleon, in the central rapidity region with medium to high pt. We have measured the inverse slopes of the mt distributions of such particles and the production ratios anti Λ/Λ, anti Ξ+/Ξ-, Ξ-/Λ, anti Ξ+/ anti Λ, K0s/Λ, K0s/ anti Λ, (Ω- + anti Ω+)/(Ξ- + anti Ξ+) and K+/K-. Preliminary results on the production ratios Ξ-/Λ and anti Ξ+/ anti Λ in pW collisions at 200 GeV/c are also presented. (orig.)

  18. Vacuum polarization effects in hyperon-rich dense matter - a nonperturbative treatment

    International Nuclear Information System (INIS)

    We derive the equation of state (EOS) for electrically charged neutral dense matter using the quantum hadrodynamics (QHD) model. This is carried out in a non-perturbative manner including quantum corrections for baryons through a realignment of vacuum with baryon-antibaryon condensates. This yields the results of relativistic Hartree approximation of summing over baryonic tadpole diagrams. The quantum corrections from the scalar meson is also taken into account in a similar way. This leads to a softening of the EOS for the hypersonic matter. The formalism also allows us to make a self-consistent calculation of the in-medium sigma meson mass. The effects of such quantum corrections on the composition of charged neutral dense matter is considered. The effect of the resulting EOS on the structure of neutron stars is also studied. (author)

  19. Baryogenesis via Hawking-like radiation in the FRW space-time

    International Nuclear Information System (INIS)

    We present a phenomenological model for baryogenesis based on particle creation in the Friedman-Robertson-Walker (FRW) space-time. This study is a continuation of our proposal that Hawking-like radiation in FRW space-time explains several physical aspects of the early Universe including inflation. In this model we study a coupling between the FRW space-time, in the form of the derivative of the Ricci scalar, and the B-L current, JB-Lμ, which leads to a different chemical potential between baryons and anti-baryons, resulting in an excess of baryons over anti-baryons with the right order of magnitude. In this model the generation of baryon asymmetry, in principle, occurs over the entire history of the Universe, starting from the beginning of the radiation phase. However, in practice, almost the entire contribution to the baryon asymmetry only comes from the very beginning of the Universe and is negligible thereafter. There is a free parameter in our model which can be interpreted as defining the boundary between the unknown quantum gravity regime and the inflation/baryogenesis regime covered by our model. When this parameter is adjusted to give the observed value of baryon asymmetry we get a higher than usual energy scale for our inflation model which, however, may be in line with the Grand Unified Theory scale for inflation in view of the BICEP2 and Planck results. In addition our model provides the correct temperature for the CMB photons at the time of decoupling. (orig.)

  20. Baryogenesis via Hawking-like radiation in the FRW space-time

    Energy Technology Data Exchange (ETDEWEB)

    Modak, Sujoy K. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico City, Distrito Federal (Mexico); Singleton, Douglas [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico City, Distrito Federal (Mexico); California State University, Department of Physics, Fresno, CA (United States)

    2015-05-15

    We present a phenomenological model for baryogenesis based on particle creation in the Friedman-Robertson-Walker (FRW) space-time. This study is a continuation of our proposal that Hawking-like radiation in FRW space-time explains several physical aspects of the early Universe including inflation. In this model we study a coupling between the FRW space-time, in the form of the derivative of the Ricci scalar, and the B-L current, J{sub B-L}{sup μ}, which leads to a different chemical potential between baryons and anti-baryons, resulting in an excess of baryons over anti-baryons with the right order of magnitude. In this model the generation of baryon asymmetry, in principle, occurs over the entire history of the Universe, starting from the beginning of the radiation phase. However, in practice, almost the entire contribution to the baryon asymmetry only comes from the very beginning of the Universe and is negligible thereafter. There is a free parameter in our model which can be interpreted as defining the boundary between the unknown quantum gravity regime and the inflation/baryogenesis regime covered by our model. When this parameter is adjusted to give the observed value of baryon asymmetry we get a higher than usual energy scale for our inflation model which, however, may be in line with the Grand Unified Theory scale for inflation in view of the BICEP2 and Planck results. In addition our model provides the correct temperature for the CMB photons at the time of decoupling. (orig.)

  1. Mass, quark-number, and √(sNN) dependence of the second and fourth flow harmonics in ultrarelativistic nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    We present STAR measurements of the azimuthal anisotropy parameter v2 for pions, kaons, protons, Λ,Λ,Ξ+Ξ, and Ω+Ω, along with v4 for pions, kaons, protons, and Λ+Λ at midrapidity for Au+Au collisions at √(sNN)=62.4 and 200 GeV. The v2(pT) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v2 values at 62.4, 130, and 200 GeV are as little as 10-15% larger than those in Pb+Pb collisions at √(sNN)=17.3 GeV. At intermediate transverse momentum (pT from 1.5-5 GeV/c), the 62.4 GeV v2(pT) and v4(pT) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon v2 is larger than antibaryon v2 at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances v2 or that antibaryon and baryon annihilation is larger in the in-plane direction

  2. CRN: 1987 Progress Report

    International Nuclear Information System (INIS)

    In the Nuclear Research Center activity report, the research works effected in each of the following departments are shown: Nuclear Physics: theoretical and experimental Nuclear Physics Works, technical studies, accomplishments and applications, the Vivitron, publications, conferences and diplomas. High Energies: theoretical and experimental Physics, the LEP-DELPHI project, the NA36 experiment (strange baryons and antibaryons production in relativistic ions collisions), technical developments, publications, conferences and diplomas. Radiation Chemistry and Physics (research reports are separated in six sections): (1) Molecular and Atomic Physics and Physical Chemistry, where the main subjects are Molecular Physics, matter-radiation interactions, positon and positronium chemistry and radiochemistry; (2) Materials Science and condensed matter studies, in which the main topics are the materials elaboration and characterization, Mossbauer spectroscopy and defect implantations; (3) Analysis and instrumentation describing short time applied Optics and sensors; (4) The nuclear reactor service with neutron activation analysis and short life radioisotopes; (5) Publications, communications, conferences, thesis and researchers' stay; (6) Technology transfers concerning accelerators, dosimetry and aliments ionization

  3. Evidence indicating that meson and baryon formation are controlled by phase space and a linear confining quark potential

    International Nuclear Information System (INIS)

    Using the relativistic string model for hadronization, we find that the two simple principles of longitudinal phase space on the hadron level and a linear confining quark potential as expressed by the 'Wilson Area Law' (a combination of principles from which the Lund Symmetric Fragmentation Function can be derived) describe a great deal of e+e- annihilation data without the need for the many (typically quark-level) parameters such as s/u, vector/All, qq/q, (su/ud)/(s/u), 1/3(qq)1/(qq)0, etc. that are commonly used. In particular, using only 2-3 parameters, we find good agreement with measured meson and baryon multiplicities and longitudinal distributions at Ecm = 29 GeV and at 10 GeV. Typically at 29 GeV a baryon and antibaryon are separated by ∼1.5 mesons in rank. Predictions are extrapolated to 60 GeV (TRISTAN) and 90 GeV (SLC/LEP). Further tests of the model are discussed. (author)

  4. Measurements of identified particles at intermediate transverse momentum in the STAR experiment from Au+Au collisions at sqrt{s_{NN}}=200 GeV

    CERN Document Server

    Adams, J; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, C O; Blyth, S L; Bonner, B E; Botje, M; Bouchet, J; Braem, André; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Choi, H A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Daugherity, M; Davenport, M; De Cataldo, G; De Moura, M M; De Phillips, M; Dedovich, T G; Derevshchikov, A A; Di Bari, D; Di Mauro, A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fornazier, K S F; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Ghazikhanian, V; Ghosh, P; González, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guo, Y; Gupta, N; Gutíerrez, T D; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krämer, M; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kuznetsov, A A; La Pointe, S; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Le Vine, M J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; López-Noriega, M; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Martinengo, P; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Miller, M L; Milos, M; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nappi, E; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Piuz, François; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Posa, E; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Schyns, E; Seger, J; Selyuzhenkov, I; Sen-Gupta, A; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Sørensen, P; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van Leeuwen, M; Van der Kolk, N; Van der Molen, A M; Varma, R; Vasilev, A N; Vasilevski, I M; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yurevich, V I; Zborovský, I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2006-01-01

    Data for Au+Au collisions at sqrt{s_{NN}}=200 GeV are analyzed to determine the ratios of identified hadrons ($\\pi$, $K$, $p$, $\\Lambda$) as functions of collision centrality and transverse momentum ($p_T$). We find that ratios of anti-baryon to baryon yields are independent of $p_T$ up to 5 GeV/c, a result inconsistent with results of theoretical pQCD calculations that predict a decrease due to a stronger contribution from valence quark scattering. For both strange and non-strange species, strong baryon enhancements relative to meson yields are observed as a function of collision centrality in the intermediate $p_T$ region, leading to $p/\\pi$ and $\\Lambda$/K ratios greater than unity. The increased $p_T$ range offered by the $\\Lambda$/K$^{0}_{S}$ ratio allows a test of the applicability of various models developed for the intermediate $p_{T}$ region. The physics implications of these measurements are discussed with regard to different theoretical models.

  5. Strange particle correlations measured by the Star experiment in ultra-relativistic heavy ion collisions a RHIC

    International Nuclear Information System (INIS)

    Non-identical correlation functions allow to study the space-time evolution of the source of particles formed in ultra-relativistic heavy ion collisions. The STAR experiment is dedicated to probe the formation of a new state of nuclear matter called Quark Gluon Plasma. The proton - lambda correlation function is supposed to be more sensitive to bigger source sizes than the proton - proton because of the absence of the final state Coulomb interaction. In this thesis, proton - lambda, anti-proton - anti-lambda, anti-proton - lambda and proton - anti-lambda correlation functions are studied in Au+Au collisions at √SNN = 200 GeV using an analytical model. The proton - lambda and anti-proton - anti-lambda correlation functions exhibit the same behavior as in previous measurements. The anti-proton - lambda and proton - anti-lambda correlation functions, measured for the first time, show a very strong signal corresponding to the baryon - anti-baryon annihilation channel. Parameterizing the correlation functions has allowed to characterize final state interactions. (author)

  6. On the hadron production from the quark-gluon plasma phase in ultra-relativistic heavy-ion collisions

    CERN Document Server

    Berdnikov, Yu A; Ivanov, A N; Ivanova, V A; Kosmach, V F; Samsonov, V M; Troitskaya, N I; Berdnikov, Ya. A.

    2000-01-01

    We describe the quark gluon plasma (QGP) as a thermalized quark-gluon system, the thermalized QGP phase of QCD. The hadronization of the thermalized QGP phase is given in a way resembling a simple coalescence model. The input parameters of the approach are the spatial volumes of the hadronization. We introduce three dimensionless parameters C_M, C_B and C_\\bar{B} related to the spatial volumes of the production of low-lying mesons (M), baryons (B) and antibaryons (\\bar{B}). We show that at the temperature T= 175 MeV our predictions for the ratios of multiplicities agree good with the presently available set of hadron ratios measured for various experiments given by NA44, NA49, NA50 and WA97 Collaborations on Pb+Pb collisions at 158 GeV/nucleon, NA35 Collaboration on S+S collisions and NA38 Collaboration on O+U and S+U collisions at 200 GeV/nucleon.

  7. Strange particle correlations measured by the Star experiment in ultra-relativistic heavy ion collisions a RHIC; Etude des correlations de particules etranges mesurees par l'experience STAR dans les collisions d'ions lourds ultra-relativistes au RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Renault, G

    2004-09-01

    Non-identical correlation functions allow to study the space-time evolution of the source of particles formed in ultra-relativistic heavy ion collisions. The STAR experiment is dedicated to probe the formation of a new state of nuclear matter called Quark Gluon Plasma. The proton - lambda correlation function is supposed to be more sensitive to bigger source sizes than the proton - proton because of the absence of the final state Coulomb interaction. In this thesis, proton - lambda, anti-proton - anti-lambda, anti-proton - lambda and proton - anti-lambda correlation functions are studied in Au+Au collisions at {radical}S{sub NN} = 200 GeV using an analytical model. The proton - lambda and anti-proton - anti-lambda correlation functions exhibit the same behavior as in previous measurements. The anti-proton - lambda and proton - anti-lambda correlation functions, measured for the first time, show a very strong signal corresponding to the baryon - anti-baryon annihilation channel. Parameterizing the correlation functions has allowed to characterize final state interactions. (author)

  8. New experiment to gain unparalleled insight into antimatter

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    At last week’s Research Board meeting, the Baryon Antibaryon Symmetry Experiment (BASE) was approved for installation at CERN. The experiment will be diving into the search for matter-antimatter asymmetry, as it aims to take ultra-high precision measurements of the antiproton magnetic moment.   CERN's AD Hall: the new home of the BASE double Penning trap set-up. The BASE collaboration will be setting up shop in the AD Hall this September with its first CERN-based experimental set-up. Using the novel double-Penning trap set-up developed at the University of Mainz, GSI Darmstadt and the Max Plank Institute for Nuclear Physics (Germany), the BASE team will be able to measure the antiproton magnetic moment with hitherto unreachable part-per-billion precision. “We constructed the first double-Penning trap at our companion facility in Germany, and made the first ever direct observations of single spin flips of a single proton,” explains Stefan Ulmer from RIKE...

  9. Precision measurement of the mass difference between light nuclei and anti-nuclei

    CERN Document Server

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

    2015-01-01

    The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons ($\\bar{d}$), and $^{3}{\\rm He}$ and $^3\\overline{\\rm He}$ nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirm CPT invariance to an unprecedented precision in the sector of light nuclei. This funda...

  10. Results on hyperon production from CERN NA57 experiment

    CERN Document Server

    Antinori, Federico; Barbera, R; Bhasin, A; Bloodworth, Ian J; Bruno, G; Bull, S A; Caliandro, R; Campbell, M; Carena, W; Carrer, N; Clarke, R F; De Haas, A P; De Rijke, P C; Di Bari, D; Di Liberto, S; Divià, R; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Fedorisin, J; Feofilov, G A; Fini, R A; Ftácnik, J; Ghidini, B; Grella, G; Helstrup, H; Henriquez, M; Holme, A K; Jacholkowski, A; Jones, G T; Jovanovic, P; Jusko, A; Kamermans, R; Kinson, J B; Knudson, K; Kolojvari, A A; Kondratev, V A; Králik, I; Kravcakova, A; Kuijer, P; Lenti, V; Lietava, R; Løvhøiden, G; Lupták, M; Manzari, V; Martinská, G; Mazzoni, M A; Meddi, F; Michalon, A; Morando, M; Muigg, D; Nappi, E; Navach, F; Norman, P I; Palmeri, A; Pappalardo, G S; Pastircák, B; Pisút, J; Pisútová, N; Posa, F; Quercigh, Emanuele; Riggi, F; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Schillings, E; Segato, G F; Sené, M; Sené, R; Snoeys, W; Soramel, F; Staroba, P; Toulina, T A; Turrisi, R; Tveter, T S; Urbán, J; Valiev, F F; Van den Brink, A; Van de Ven, P; Van de Vyvre, P; van Eijndhoven, N; Van Hunen, J J; Vascotto, Alessandro; Vik, T; Villalobos Baillie, O; Vinogradov, L I; Virgili, T; Vortruba, M F; Vrakova, J; Závada, P

    2001-01-01

    NA57 has been specifically designed to study, the onset of strange baryon and antibaryon enhancements in Pb-Pb with respect to p-Be collisions, first observed by the WA97 experiment at 160 A GeV/c beam momentum. The aim is to look for the dependence of these enhancements on the interaction volume, as measured by the number of wounded nucleons, and the energy per incoming nucleon. In NA57 the centrality range goes down to a lower limit of about 50 wounded nucleons, compared with about 100 in WA97. Data have been collected both at 160 and at 40 A GeV/c, while WA97 collected data only at the top SPS beam momentum of 160 A GeV/c. In this contribution we recall the main features of the NA57 experiment and we present the first results on Xi /sup -/ and Xi /sup +/ hyperon production in Pb-Pb collisions at 160 A GeV/c. (10 refs).

  11. Photoproduction of the. Lambda. sub c charmed baryon

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, M.P.; Calvino, F.; Crespo, J.M. (Universidad Autonoma de Barcelona (Spain)); Barate, R.; DiCiaccio, L.; Ferrer, A.; Giomataris, Y.; Pattison, B.; Treille, D.; Zolnierowski, Y. (European Organization for Nuclear Research, Geneva (Switzerland)); Bloch, D.; Engel, J.P.; Foucault, P.; Gerber, J.P.; Strub, R. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires Strasbourg-1 Univ., 67 (France)); Bonamy, P.; Borgeaud, P.; David, M.; Lemoigne, Y.; Magneville, C.; Primout, M.; Villet, G. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Physique des Particules Elementaires); Burchell, M.; Burmeister, H.; Cattaneo, M.; Dixon, J.; Duane, A.; Forty, R.W.; Seez, C.; Websdale, D.M. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.); Brunet, J.M.; Poutot, D.; Triscos, P.; Tristram, G.; Volte, A. (College de France, 75 - Paris (France)); Almagne, B. d' ; Druet, P.; Krafft, C.; Lefievre, B.; Roudeau, P.; Six, J.; Wayne, M.; NA14/2 Collaboration

    1990-08-23

    In a photoproduction experiment using a mean photon energy of 100 GeV we have observed 29{plus minus}8 {Lambda}{sub c} (anti {Lambda}{sub c}) charmed-baryon and antibaryon decays in the pK{sup -}{pi}{sup +} (anti pK{sup +}{pi}{sup -}) final state. Quasi two-body final states do not contribute significantly to this channel. The mass of the {Lambda}{sub c} was measured to be 2281.7{plus minus}2.7{plus minus}2.6 MeV/c{sup 2} and its lifetime 0.18{plus minus}0.03{plus minus}0.03 ps. The ratio of {Lambda}{sub c}/D production, measured in this experiment, is significantly greater than that predicted by photon-gluon fusion and using a Lund model to describe the hadronization. This excess cannot be completely accounted for in this model, even using a {Lambda}{sub c} branching fraction in pK{pi} as high as 5%. (orig.).

  12. A tetraquark or not a tetraquark: A holography inspired stringy hadron (HISH) perspective

    CERN Document Server

    Sonnenschein, Jacob

    2016-01-01

    We suggest to use the state $Y(4630)$, which decays predominantly to $\\Lambda_c\\bar\\Lambda_c$, as a window to the landscape of tetraquarks. We propose a simple criterion to decide whether a state is a genuine stringy exotic hadron - a tetraquark - or a "molecule". If it is the former it should be on a (modified) Regge trajectory. We present the predictions of the mass and width of the higher excited states on the $Y(4630)$ trajectory. We argue that there should exist an analogous "$Y_b$" state that decays to $\\Lambda_b\\bar\\Lambda_b$ and describe its trajectory. We conjecture also a similar trajectory for tetraquarks containing strange quarks, and the modified Regge trajectories can in fact be predicted for any resonances found decaying to a baryon-antibaryon pair. En route to the results regarding tetraquarks, we also make some additional predictions on higher excited charmonium states. We briefly discuss the zoo of exotic stringy hadrons and in particular we sketch all the possibilities of tetraquark states.

  13. Double pion production in $NN$ and $\\bar{N}N$ collisions

    CERN Document Server

    Cao, Xu; Xu, Hu-Shan

    2010-01-01

    With an effective Lagrangian approach, we give a full analysis on the $NN \\to NN\\pi\\pi$ and $\\bar{N}N\\to \\bar{N}N\\pi\\pi$ reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from $\\Delta$, $N^*(1440)$, $\\Delta(1600)$ and $\\Delta(1620)$ resonances. Our calculations also indicate sizeable contributions from nucleon poles for the energies close to the threshold. A good description to the existing data of different isospin channels of $NN\\to NN\\pi\\pi$ and $\\bar{N}N\\to \\bar{N}N\\pi\\pi$ for beam energies up to 2.2 GeV is reached. Our results provide important implications to the ABC effect and guildlines to the future experimental projects at COSY, HADES and HIRFL-CSR. We point out that the \\={P}ANDA at FAIR could be an essential place for studying the properties of baryon resonances and the data with baryon and anti-baryon in final states are worth analyzing.

  14. 13th workshop on what comes beyond the standard models

    CERN Document Server

    Nielsen, Holger Bech; Lukman, Dragan

    2010-01-01

    1. Noncommutativity and Topology within Lattice Field Theories 2. The Construction of Quantum Field Operators 3. The Bargmann-Wigner Formalism for Spin 2 Fields 4. New Light on Dark Matter from the LHC 5. Extra Dimensional Metric Reversal Symmetry and its Prospect... 6. Masses and Mixing Matrices of Families within SU(3) Flavor Symmetry ... 7. Dark Atoms of the Universe: OHe Nuclear Physics, 8. Can the Matter-Antimatter Asymmetry be Easier to Understand Within the "Spin-charge-family-theory", .. 9. Mass Matrices of Twice Four Families of Quarks and Leptons, ...in the "Spin-charge-family-theory" 10. Bohmian Quantum Mechanics or What Comes Before the Standard Model 11. Backward Causation in Complex Action Model ... 12. Is the Prediction of the "Spin-charge-family-theory" in Disagreement with the XENON100..? 13. Masses and Mixing Matrices of Families of Quarks and Leptons Within the "Spin-charge-family-theory" 14. Can the Stable Fifth Family of the "Spin-charge-family-theory" ...Form the Fifth Antibaryon Cluster...

  15. External meeting - Geneva University: Proposal to measure the muon electric dipole moment with a compact storage ring at PSI

    CERN Multimedia

    2007-01-01

    GENEVA UNIVERSITY ECOLE DE PHYSIQUE Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 ? Tél : 022 379 62 73 - Fax: 022 379 69 92 Wednesday 16th May  2007 PARTICLE PHYSICS SEMINAR at 17:00 - Stückelberg Auditorium Proposal to measure the muon electric dipole moment with a compact storage ring at PSI by Dr. Thomas Schietinger, PSI - Villigen In the Standard Model, lepton electric dipole moments (EDM) arise from the CP-violating phase in the CKM matrix at the three-loop level only, resulting in values that are many orders of magnitude below the sensitivity of current and future experiments. Lepton EDMs therefore offer an excellent opportunity to discover unambiguous evidence for new CP-violating phases, as called for by the baryon-antibaryon asymmetry of the universe. The muon EDM is one of the least constrained fundamental properties in elementary particle physics. We propose to utilize the large available flux of polarized muons at PSI to search for a muon EDM ...

  16. New Exotic Meson and Baryon Resonances from Doubly Heavy Hadronic Molecules.

    Science.gov (United States)

    Karliner, Marek; Rosner, Jonathan L

    2015-09-18

    We predict several new exotic doubly heavy hadronic resonances, inferring from the observed exotic bottomoniumlike and charmoniumlike narrow states X(3872), Z_{b}(10610), Z_{b}(10650), Z_{c}(3900), and Z_{c}(4020/4025). We interpret the binding mechanism as mostly molecularlike isospin-exchange attraction between two heavy-light mesons in a relative S-wave state. We then generalize it to other systems containing two heavy hadrons which can couple through isospin exchange. The new predicted states include resonances in meson-meson, meson-baryon, baryon-baryon, and baryon-antibaryon channels. These include those giving rise to final states involving a heavy quark Q=c,b and antiquark Q[over ¯]^{'}=c[over ¯],b[over ¯], namely, DD[over ¯]^{*}, D^{*}D[over ¯]^{*}, D^{*}B^{*}, B[over ¯]B^{*}, B[over ¯]^{*}B^{*}, Σ_{c}D[over ¯]^{*}, Σ_{c}B^{*}, Σ_{b}D[over ¯]^{*}, Σ_{b}B^{*}, Σ_{c}Σ[over ¯]_{c}, Σ_{c}Λ[over ¯]_{c}, Σ_{c}Λ[over ¯]_{b}, Σ_{b}Σ[over ¯]_{b}, Σ_{b}Λ[over ¯]_{b}, and Σ_{b}Λ[over ¯]_{c}, as well as corresponding S-wave states giving rise to QQ^{'} or Q[over ¯]Q[over ¯]^{'}. PMID:26430989

  17. Detailed discussion of a linear electric field frequency shift induced in confined gases by a magnetic field gradient: Implications for neutron electric-dipole-moment experiments

    International Nuclear Information System (INIS)

    The search for particle electric dipole moments (EDM's) is one of the best places to look for physics beyond the standard model of electroweak interaction because the size of time reversal violation predicted by the standard model is incompatible with present ideas concerning the creation of the baryon-antibaryon asymmetry. As the sensitivity of these EDM searches increases more subtle systematic effects become important. We develop a general analytical approach to describe a systematic effect recently observed in an electric dipole moment experiment using stored particles [J. M. Pendlebury et al., Phys. Rev. A 70, 032102 (2004)]. Our approach is based on the relationship between the systematic frequency shift and the velocity autocorrelation function of the resonating particles. Our results, when applied to well-known limiting forms of the correlation function, are in good agreement with both the limiting cases studied in recent work that employed a numerical and heuristic analysis. Our general approach explains some of the surprising results observed in that work and displays the rich behavior of the shift for intermediate frequencies, which has not been studied previously

  18. Axion field and the quark nugget's formation at the QCD phase transition

    CERN Document Server

    Liang, Xunyu

    2016-01-01

    We study a testable dark matter (DM) model outside of the standard WIMP paradigm in which the observed ratio $\\Omega_{\\rm dark} \\simeq \\Omega_{\\rm visible}$ for visible and dark matter densities finds its natural explanation as a result of their common QCD origin when both types of matter (DM and visible) are formed at the QCD phase transition and both are proportional to $\\Lambda_{\\rm QCD}$. Instead of conventional "baryogenesis" mechanism we advocate a paradigm when the "baryogenesis" is actually a charge separation process which always occur in the presence of the $\\cal{CP}$ odd axion field $a(x)$. In this scenario the global baryon number of the Universe remains zero, while the unobserved anti-baryon charge is hidden in form of heavy nuggets, similar to Witten's strangelets and compromise the DM of the Universe. We argue that the nuggets will be inevitably produced during the QCD phase transition as a result of Kibble-Zurek mechanism on formation of the topological defects during a phase transition. Relev...

  19. Quark-gluon plasma versus hadron gas. What one can learn from hadron abundances

    International Nuclear Information System (INIS)

    We use a phenomenological equation of state to describe the phase transition between a hot and dense hadron resonance gas and a quark-gluon plasma. Our analysis covers the entire temperature-baryon density plane. The consequences for the phase diagram of strangeness conservation during nuclear collisions are analyzed. The flavor composition of the quark plasma and an equilibrated hadron resonance gas is studied and compared along the phase transition surface. We emphasize the need to compare systems with equal total baryon number and entropy contents in order to be consistent with the dynamics of the hadronization process and to obtain results relevant to nuclear collisions. From our results we conclude that the flavor composition of the hadronization debris from a quark-gluon plasma formed in a nuclear collision is probably hard to distinguish from that of a chemically equilibrated hadron gas, although in both cases the production level of strange and nonstrange antibaryons will be much higher than observed in proton-proton collisions

  20. Measurement of the Branching Fractions of the Decays \\bar{B}^0 to Lambda_c^+ \\bar{p} and B^- to Lambda_c^+ \\bar{p} pi^-

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona; Palano, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B.; /Bergen U.; Abrams, G.S.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC,

    2006-12-06

    The authors present studies of two-body and three-body charmed baryonic B decays in a sample of 232 million B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. The branching fractions of the decays {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p} and B{sup -} {yields} {Lambda}{sub c}{sup +} {bar p}{pi}{sup -} are measured to be (2.15 {+-} 0.36 {+-} 0.13 {+-} 0.56) x 10{sup -5} and (3.53 {+-} 0.18 {+-} 0.31 {+-} 0.92) x 10{sup -4}, respectively. The uncertainties quoted are statistical, systematic, and from the {Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +} branching fraction. They observe a baryon-antibaryon threshold enhancement in the {Lambda}{sub c}{sup +}{bar p} invariant mass spectrum of the three-body mode and measure the ratio of the branching fractions to be {Beta}(B{sup -} {yields} {Lambda}{sub c}{sup +}{bar p}{pi}{sup -})/{Beta}({bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p}) = 16.4 {+-} 2.9 {+-} 1.4. These results are preliminary.

  1. Double Pion Production in NN and bar NN Collisions

    Science.gov (United States)

    Cao, Xu; Zou, Bing-Song; Xu, Hu-Shan

    With an effective Lagrangian approach, we give a full analysis on the NN → NNππ and bar NN -> bar NNπ π reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from Δ, N*(1440), Δ(1600) and Δ(1620) resonances. Our calculations also indicate sizeable contributions from nucleon poles for the energies close to the threshold. A good description to the existing data of different isospin channels of NN → NNππ and bar NN -> bar NNπ π for beam energies up to 2.2 GeV is reached. Our results provide important implications to the ABC effect and guildlines to the future experimental projects at COSY, HADES and HIRFL-CSR. We point out that the {bar PANDA} at FAIR could be an essential place for studying the properties of baryon resonances and the data with baryon and anti-baryon in final states are worth analyzing.

  2. Mass, quark-number, and $\\sqrt{s_{NN}}$ dependence of the second and fourth flow harmonics in ultra-relativistic nucleus-nucleus collisions

    CERN Document Server

    Abelev, B I; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S L; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Callner, J; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, S U; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Dash, S; Daugherity, M; De Moura, M M; De Phillips, M; Dedovich, T G; Derevshchikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; García-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guimaraes, K S F F; Gupta, N; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D; Hollis, R; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kurnadi, P; Kuznetsov, A A; La Pointe, S; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Le Vine, M J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, N S; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Yu A; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Qattan, I A; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Suarez, M C; Subba, N L; Sugarbaker, E R; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Sørensen, P; Takahashi, J; Tang, A H; Tarnowsky, T J; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van Leeuwen, M; Van der Kolk, N; Van der Molen, A M; Varma, R; Vasilev, A N; Vasilevski, I M; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2007-01-01

    We present STAR measurements of the azimuthal anisotropy parameter $v_2$ for pions, kaons, protons, $\\Lambda$, $\\bar{\\Lambda}$, $\\Xi+\\bar{\\Xi}$, and $\\Omega + \\bar{\\Omega}$, along with $v_4$ for pions, kaons, protons, and $\\Lambda + \\bar{\\Lambda}$ at mid-rapidity for Au+Au collisions at $\\sqrt{s_{_{NN}}}=62.4$ and 200 GeV. The $v_2(p_T)$ values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, $v_2$ values at 62.4, 130, and 200 GeV are as little as 10%--15% larger than those in Pb+Pb collisions at $\\sqrt{s_{_{NN}}}=17.3$ GeV. At intermediate transverse momentum ($p_T$ from 1.5--5 GeV/c), the 62.4 GeV $v_2(p_T)$ and $v_4(p_T)$ values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the non-flow contributions to pions and protons and some indications are found for a smaller non-flow contribution to protons than pions. Baryon $v_2$ is larger than anti-baryon $v_2...

  3. Measurements of Strange Particle Production in $p+p$ Collisions at $\\sqrt{s}$= 200 GeV

    CERN Document Server

    Abelev, B; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S L; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Dash, S; Daugherity, M; De Moura, M M; Dedovich, T G; De Phillips, M; Derevshchikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta-Majumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Ghazikhanian, V; Ghosh, P; González, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guimaraes, K S F F; Gupta, N; Gutíerrez, T D; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; La Pointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C H; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnik, Yu M; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van der Kolk, N; Van Leeuwen, M; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2006-01-01

    We present strange particle spectra and yields measured at mid-rapidity in $\\sqrt{\\text{s}}=200$ GeV proton-proton ($p+p$) collisions at RHIC. We find that the previously observed universal transverse mass ($\\mathrm{m_{T}}\\equiv\\sqrt{\\mathrm{p_{T}}^{2}+\\mathrm{m}^{2}}$) scaling of hadron production in $p+p$ collisions seems to break down at higher \\mt and that there is a difference in the shape of the \\mt spectrum between baryons and mesons. We observe mid-rapidity anti-baryon to baryon ratios near unity for $\\Lambda$ and $\\Xi$ baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum (\\mpt) on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared to previous measurements from CERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next to Leading order ...

  4. Production of ultra cold neutrons with a solid deuterium converter; Produktion von ultrakalten Neutronen mit einem festen Deuteriumkonverter

    Energy Technology Data Exchange (ETDEWEB)

    Frei, Andreas

    2008-10-28

    Spontaneous breaking of fundamental symmetries is an attractive topic in modern particle physics. Understanding qualitative and quantitative the parameters involved in these kind of processes could help to explain the unbalanced presence in the universe of matter (baryons) with respect to antimatter (anti-baryons). Due to their intrinsic properties, ultra cold neutrons (UCN) are excellent candidates for experiments measuring with high level of accuracy parameters like the electric dipole moment (EDM), the neutron lifetime ({tau}{sub n}), the axial-vector coupling constant (g{sub A}), or in search of quantum effects of gravity. In this work the setup of a source for ultra cold neutrons with a solid deuterium converter is described, which serves as a prototype for a new, strong UCN source, that is currently designed and constructed at the FRMII in Garching. The prototype source has been taken into operation and important parameters have been measured. These experimental results have been compared with theoretical models to prove calculations for the performance of the new source at the FRMII. (orig.)

  5. A report of the working group on the present and future status of medium and high energy physics

    International Nuclear Information System (INIS)

    This is a report of the working group on the present and future status of medium and high energy physics. The heavy ion nuclear physics has been developed. On the other hand, the study of nuclear structure made clear the rotational motion of high spin state and its competition with the independent particle model. The development of new many body nucleon system is expected. The hadrons in nuclei and the multiple production of elementary particles may be future problems in high energy nucleus-nucleus collision. The topics discussed in this report are the recent study of unstable nuclei by using heavy ions, nuclear reaction with various nuclear density, nuclear physics in high temperature region, hyper nuclear physics, nuclear physics with π, K mesons, nuclear physics of anti-baryon, physics of small number of nucleons, the cascade model in high energy heavy ion reaction, the new phase of nuclear many body systems, high energy nucleus-nucleus collision, physics expected from high energy heavy ion collision, and quark gluon plasma formation in heavy ion collision. The relation between space physics and high energy heavy ion physics is also discussed. (Kato, T.)

  6. Limits on Cosmic Matter--Antimatter Domains from Big Bang Nucleosynthesis

    CERN Document Server

    Rehm, J B; Rehm, Jan B.; Jedamzik, Karsten

    2001-01-01

    We present detailed numerical calculations of the light element abundances synthesized in a Universe consisting of matter- and antimatter- domains, as predicted to arise in some electroweak baryogenesis scenarios. In our simulations all relevant physical effects, such as baryon-antibaryon annihilations, production of secondary particles during annihilations, baryon diffusion, and hydrodynamic processes are coupled to the nuclear reaction network. We identify two dominant effects, according to the typical spatial dimensions of the domains. Small antimatter domains are dissipated via neutron diffusion prior to He4 synthesis at T_He4 \\approx 80 keV, leading to a suppression of the primordial He4 mass fraction. Larger domains are dissipated below T_He4 via a combination of proton diffusion and hydrodynamic expansion. In this case the strongest effects on the elemental abundances are due to anti-p He4 annihilations, leading to an overproduction of He3 relative to H2 and to overproduction of Li6 via non-thermal nuc...

  7. Strange hadron production at low transverse momenta

    Science.gov (United States)

    Veres, Gábor I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyslouch, B.; Zhang, J.

    2004-01-01

    Some of the latest results of the PHOBOS experiment from the \\sqrt{s_{NN}}= 200\\ GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision. Finally, we describe the upgrades of PHOBOS completed for the 2003 d+Au and p+p run, which extend the transverse momentum range over which particle identification is possible and, at the same time, implement a trigger system selective for high-pT particles.

  8. Some cosmological consequences of primordial black-hole evaporations

    International Nuclear Information System (INIS)

    According to Hawking, primordial black holes of less than 1015 g would have evaporated by now. This paper examines the way in which small primordial black holes could thereby have contributed to the background density of photons, nucleons, neutrinos, electrons, and gravitons in the universe. Any photons emitted late enough should maintain their emission temperature apart from a redshift effect: it is shown that the biggest contribution should come from primordial black holes of about 1015 g, which evaporate in the present era, and it is argued that observations of the γ-ray background indicate that primordial black holes of this size must have a mean density less than 10-8 times the critical density. Photons which were emitted sufficiently early to be thermalized could, in principle, have generated the 3 K background in an initially cold universe, but only if the density fluctuations in the early universe had a particular form and did not extend up to a mass scale of 1015 g. Primordial black holes of less than 1014 g should emit nucleons: it is shown that such nucleons could not contribute appreciably to the cosmic-ray background. However, nucleon emission could have generated the observed number density of baryons in an initially baryon-symmetric universe, provided some CP-violating process operates in black hole evaporations such that more baryons are always produced than antibaryons. We predict the spectrum of neutrinos, electrons, and gravitons which should result from primordial black-hole evaporations and show that the observational limits on the background electron flux might place a stronger limitation on the number of 1015 g primordial black holes than the γ-ray observations. Finally, we examine the limits that various observations place on the strength of any long-range baryonic field whose existence might be hypothesized as a means of preserving baryon number in black-hole evaporations

  9. Search for popcorn mesons in events with two charmed baryons

    Science.gov (United States)

    Hartfiel, Brandon

    The physics of this dissertation is divided into two parts. The first part measures the Λc → pi kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c, which is just below the Υ(4s) resonance. The data sample consists of 15,400 Λc baryons from 9.46 fb-1 of integrated luminosity collected with the BaBar detector at the PEP-II asymmetric B factory at the Stanford Linear Accelerator Center. With more than 13 times more data than the best previous measurement, we are able to exclude some of the simpler, one parameter fragmentation functions. In the second part, we add the Λc → K0p mode, and look for events with a Λc+ and a Λ c- in order to look for "popcorn" mesons formed between the baryon and antibaryon. We add on-resonance data, with a kinematic cut to eliminate background from B decays, as well as BaBar run 3 and 4 data to increase the total data size to 219.70 fb-1. We find 619 events after background subtraction. After a subtraction of 1.06+/-.09 charged pions coming from decays of known resonances to Λc + npi, we are left with 2.63+/-.21 additional charged pious in each of these events. This is significantly higher than the .5 popcorn mesons per bayon pair used in the current tuning of Pythia 6.2, the most widely used Monte Carlo generator. The extra mesons we find appear to be the first direct evidence of popcorn mesons, although some of them could be arising from hypothetical unresolved, unobserved charmed baryon resonances contributing decay mesons to our data. To contribute a significant fraction, this hypothesis requires a large number of such broad unresolved states and seems unlikely, but can not be completely excluded.

  10. Search for Popcorn Mesons in Events with Two Charmed Baryons

    Energy Technology Data Exchange (ETDEWEB)

    Hartfiel, Brandon; /SLAC

    2006-07-07

    The physics of this note is divided into two parts. The first part measures the {Lambda}{sub c} {yields} {pi}kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c. The data sample consists of 15,400 {Lambda}{sub c} baryons from 9.46 fb{sup -1} of integrated luminosity. With more than 13 times more data than the best previous measurement, we are able to exclude some of the simpler, one parameter fragmentation functions. In the second part, we add the {Lambda}{sub c} {yields} K{sup 0}p mode, and look for events with a {Lambda}{sub c}{sup +} and a {bar {Lambda}}{sub c}{sup -} in order to look for ''popcorn'' mesons formed between the baryon and antibaryon. We add on-resonance data, with a kinematic cut to eliminate background from B decays, as well as BaBar run 3 and 4 data to increase the total data size to 219.70 fb{sup -1}. We find 619 events after background subtraction. After a subtraction of 1.06 {+-} .09 charged pions coming from decays of known resonances to {Lambda}{sub c} + {eta}{pi}, we are left with 2.63 {+-} .21 additional charged pions in each of these events. This is significantly higher than the .5 popcorn mesons per baryon pair used in the current tuning of Pythia 6.2, the most widely used Monte Carlo generator. The extra mesons we find appear to be the first direct evidence of popcorn mesons, although some of them could be arising from hypothetical unresolved, unobserved charmed baryon resonances contributing decay mesons to our data. To contribute a significant fraction, this hypothesis requires a large number of such broad unresolved states and seems unlikely, but can not be completely excluded.

  11. Physical interpretation of the combinatorial hierarchy

    International Nuclear Information System (INIS)

    The combinatorial hierarchy model for base particle processes is compared and contrasted with the Ur-theory as developed at the Tutzing Conferences. It agrees with Ur-theory about a finite basis, the ''fixed past--uncertain future'' aspects of physics, and the necessity of dropping Bohr's requirement of reduction to the haptic language of commonsense and classical physics. However, it retains a constructive, hierarchial approach with can yield only an approximate and discrete ''space time'', and introduces the observation metaphysic at the start. Concrete interpretation of the four levels of the hierarchy (with cardinals 3, 7, 127, 2127-1 approx. =1038) associates the three levels which map up and down with three absolute conservation laws (charge, baryon number, lepton number) and the spin dichotomy. The first level represents +, -, and +- unit charge. The second has the quantum nubmers of a baryon--antibaryon pair and associated charged meson (e.g., n anti n, p anti n, p anti p, n anti p, π+, π0, π-). The third level associates this pair, now including four spin states as well as four charge states, with a neutral lepton--antilepton pair (e anti e or ν anti ν) in four spin states (total, 64 states): three charged spinless, three charged spin-1, and neutral spin-1 mesons (15 states), and a neutral vector boson associated with the leptons; this gives 3 + 15 + 3 x 15 = 63 possible boson states, so a total correct count of 63 + 64 = 127 states. Something like SU2 X SU3 and other indications of quark quantum numbers can occur as substructures at the fourth (unstable) level. A slight extension gives the usual static approximation to the building energy of the hydrogen atom, α2m/sub e/c2. Cosmological implications of the theory are in accord with current experience. A beginning in the physical interpretation of a theory which could eventually encompass all branches of physics was made. 3 figures, 6 tables

  12. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ON BARYON DYNAMICS AT RHIC, MARCH 28-30, 2002, BROOKHAVEN NATIONAL LABORATORY

    International Nuclear Information System (INIS)

    One of the striking observations at RHIC is the large valence baryon rapidity density observed at mid rapidity in central Au+Au at 130 A GeV. There are about twice as many valence protons at mid-rapidity than predicted based on extrapolation from p+p collisions. Even more striking PHENIX observed that the high pt spectrum is dominated by baryons and anti-baryons. The STAR measured event anisotropy parameter v2 for lambdas are as high as charged particles at pt ∼ 2.5 GeV/c. These are completely unexpected based on conventional pQCD parton fragmentation phenomenology. One exciting possibility is that these observables reveal the topological gluon field origin of baryon number transport referred to as baryon junctions. Another is that hydrodynamics may apply up to high pt in A+A. There is no consensus on what are the correct mechanisms for producing baryons and hyperons at high pt and large rapidity shifts and the new RHIC data provide a strong motivation to hold a meeting focusing on this class of observables. The possible role of junctions in forming CP violating domain walls and novel nuclear bucky-ball configurations would also be discussed. In this workshop, we focused on all measured baryon distributions at RHIC energies and related theoretical considerations. To facilitate the discussions, results of heavy ion collisions at lower beam energies, results from p+A /p+p/e+e collisions were included. Some suggestions for future measurements have been made at the workshop

  13. Exclusive and inclusive weak decays of the B-meson

    Energy Technology Data Exchange (ETDEWEB)

    Grach, I.L.; Narodetskii, I.M.; Ter-Martirosyan, K.A. [Institute of Theor. and Exp. Phys., Moscow (Russian Federation); Simula, S. [Istituto Nazionale di Fisica Nucleare, Sezione Sanita, Viale Regina Elena 299, I-00161 Rome (Italy)

    1997-09-29

    A relativistic quark model is applied to the description of semileptonic and non-leptonic charmed decays of the B-meson. The exclusive semileptonic modes B{yields}Dl{nu}{sub l} and B{yields}D{sup *}l{nu}{sub l} are described through the universal Isgur-Wise form factor, which is calculated in terms of a constituent quark model wave function for the B-meson. Different approximations for the latter, either based on a phenomenological ansatz or derived from analyses of the meson spectra, are adopted. In particular, two wave functions, constructed via the Hamiltonian light-front formalism using a relativized and a non-relativistic constituent quark model, are considered, obtaining a link between standard spectroscopic quark models and the B-meson decay physics. The inclusive semileptonic and non-leptonic branching ratios are calculated within a convolution approach, inspired by the partonic model and involving the same B-meson wave function used for the evaluation of the exclusive semileptonic modes. Our results for the major branching ratios are consistent with available experimental data and the sum of all the calculated branchingratios turns out to be close to unity. In particular, we found that (i) a remarkable fraction ({proportional_to}35%) of semileptonic decay modes occur in non-D, non-D{sup *} final states; (ii) non-perturbative effects enhance the inclusive b{yields}c anti ud decay channels, with a sizable contribution provided by internal decays into heavy mesons and baryon-antibaryon pairs; the resulting reduction of the semileptonic branching ratio brings the theoretical prediction in agreement with the experimental value without increasing at the same time the charm counting. (orig.). 47 refs.

  14. Hadronic model for the consistent description of the scattering and annihilation of the antinucleon-nucleon system

    International Nuclear Information System (INIS)

    In this work a consistent description of the anti NN scattering and annihilation with a hadronic model is presented. The elastic anti NN interaction is obtained from the Bonn NN potential via a G-parity transformation. For the annihilation part, a consistent, partly microscopic description is constructed treating the most important two meson channels explicitly and accounting for the rest by a phenomenological optical potential of Gaussian form. Transitions from the antibaryon-baryon sector to the meson sector are mediated via the exchange of N, Δ, Λ, Σ and Y* baryons. anti NN scattering observables, branching ratios and cross sections for the annihilation into two mesons and bound states are calculated consistently. Results are compared with former calculations and the experimental data. The agreement with the data is good. The importance of meson-meson interactions in the final state is studied at the example of the particular annihilation channel anti NN → ππ. A full coupled channels calculation with the channels anti NN, ππ, anti KK and ρρ is performed. Interactions and transitions in the meson sector are described by meson-exchange diagrams. Integrated as well as differential cross sections and analyzing powers for the annihilation process anti NN → ππ are described with good quality. Results of the coupled channels model for ππ phase shifts and inelasticities above the anti NN threshold are discussed. Effects of the meson-meson interactions on anti NN scattering observables are small. The importance of two-step processes and meson-meson interactions in the final state for the description of the angle-dependent observables in the annihilation process anti NN → ππ can be demonstrated. (orig.)

  15. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ON BARYON DYNAMICS AT RHIC, MARCH 28-30, 2002, BROOKHAVEN NATIONAL LABORATORY.

    Energy Technology Data Exchange (ETDEWEB)

    GYULASSY,M.; KHARZEEV,D.; XU,N.

    2002-03-28

    One of the striking observations at RHIC is the large valence baryon rapidity density observed at mid rapidity in central Au+Au at 130 A GeV. There are about twice as many valence protons at mid-rapidity than predicted based on extrapolation from p+p collisions. Even more striking PHENIX observed that the high pt spectrum is dominated by baryons and anti-baryons. The STAR measured event anisotropy parameter v2 for lambdas are as high as charged particles at pt {approx} 2.5 GeV/c. These are completely unexpected based on conventional pQCD parton fragmentation phenomenology. One exciting possibility is that these observables reveal the topological gluon field origin of baryon number transport referred to as baryon junctions. Another is that hydrodynamics may apply up to high pt in A+A. There is no consensus on what are the correct mechanisms for producing baryons and hyperons at high pt and large rapidity shifts and the new RHIC data provide a strong motivation to hold a meeting focusing on this class of observables. The possible role of junctions in forming CP violating domain walls and novel nuclear bucky-ball configurations would also be discussed. In this workshop, we focused on all measured baryon distributions at RHIC energies and related theoretical considerations. To facilitate the discussions, results of heavy ion collisions at lower beam energies, results from p+A /p+p/e+e collisions were included. Some suggestions for future measurements have been made at the workshop.

  16. The PANDA detector and its physics program at FAIR

    International Nuclear Information System (INIS)

    The PANDA detector will make use of the antiprotons produced in the FAIR complex and stored in the High-Energy Storage Ring HESR for the study of strong interactions in antiproton collisions with protons and heavy targets. The detector features a 4π design for charged particles with a solenoidal magnetic field and full coverage of photons by means of an advanced electromagnetic calorimeter. In addition, a dipole spectrometer will allow high-resolution detection of leading particles characteristic for fixed-target experiments. The physics program of PANDA covers a wide range of topics which address central issues of QCD at low and moderate energies. Spectroscopy of hidden charm in the ccbar level scheme is still a very interesting issue, in particular when states are involved which cannot directly be formed in e+e- reactions. Open charm in the D meson section has recently received renewed interest when states were discovered that are not easily explained in conventional qqbar models. Exotic hadrons and glueballs have been predicted by theory within the energy range covered by PANDA. The search for these and the eventual study of their properties is central to the physics program. Using heavy targets, PANDA intends to study the properties of charm quarks in the hadronic medium. The copious production of baryon-antibaryon pairs at HESR will allow studies using secondary targets for the formation of hypernuclei. Each of these physics topics will be touched while the detector properties needed in order to cover the broad physics program are described. Technical developments and the status of the various detector components will be summarized

  17. Mass, Matter, Materialization, Mattergenesis and Conservation of Charge

    Science.gov (United States)

    Tsan, Ung Chan

    2013-05-01

    . Assumption of a novel interaction MC conserving (A-L) but violating simultaneously A and L (not trivial case of conservation) would allow energy to be transformed into a pair of baryon lepton or into a pair of antibaryon antilepton of opposite charges. This model could explain the asymmetric but nevertheless electrically neutral Universe but could not account for the numerical value of the tiny excess of matter over antimatter. The concept of anti-Universe would be superfluous. Observation of matter nonconservation processes would be of great interest to falsify this speculation.

  18. SQUIDs as Detectors in a New Experiment to Measure the Neutron Electric Dipole Moment

    Energy Technology Data Exchange (ETDEWEB)

    Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H., Jr.; Matlachov, A.; Ruminer, P.

    1998-09-13

    A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precession frequency of the spin-polarized {sup 3}He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2x10{sup {minus}16} Tm{sup 2} (0.1 F{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d F{sub SQ}=2x10{sup {minus}6} F{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application we designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and we developed a two-SQUID readout system that will reduce SQUID noise in the experiment. We present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. We also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique

  19. Mass, matter, materialization, mattergenesis and conservation of charge

    International Nuclear Information System (INIS)

    model. Assumption of a novel interaction MC conserving (A–L) but violating simultaneously A and L (not trivial case of conservation) would allow energy to be transformed into a pair of baryon lepton or into a pair of antibaryon antilepton of opposite charges. This model could explain the asymmetric but nevertheless electrically neutral Universe but could not account for the numerical value of the tiny excess of matter over antimatter. The concept of anti-Universe would be superfluous. Observation of matter nonconservation processes would be of great interest to falsify this speculation. (author)

  20. Structure of Vacuum: Supercritical Fields

    International Nuclear Information System (INIS)

    The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers are reviewed. Different ways of nuclear decay are discussed like cluster radioactivity, cold fission and cold multifragmentation. Up to now superheavy nuclei were only produced close to the proton drip line. The recent Dubna experiments utilizing a 48Ca beam have been at an essential intermediate decay at GSI. Thus we can state that superheavy nuclei up to Z=118 have been found. In order to make superheavies closer to the stable valley by increasing the neutron number we investigate the bombardment of e.g. U+Cm and its decay down to the superheavy island around Z=114 and 120. In this connection also the time delay in the formation of the giant nuclear system U+Cm up to 10-19 see is found. This is most important for studying the decay of the supercritical electron positron vacuum. A trigger for such long delay times is large mass transfer, e.g. U+Cm --->Pb+rest. In this connection the basics of the decay of the vacuum in supercritical Coulomb fields is reminded. The last part is devoted to these questions. A perspective for future research is given. This includes also a theoretical study of superheavy element (SHE) formation by supernova explosions and thus to the occurrence of SHE in nature. Furthermore, investigations on hypernuclei and the possible production of antimatterclusters in heavy-ion collisions are reported. Various versions of the meson field theory serve as effective field theories as the basis of modem nuclear structure and suggest structure in the vacuum which might be important for the production of hyper- and antimatter. It also discuss the possibility of producing a new kind of nuclear systems by putting a few antibaryons inside ordinary nuclei. This leads to surprising results: in particular to coid compression of nuclear matter- in contrast to hot compression via nuclear shock

  1. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the STAR detector

    Science.gov (United States)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Silva, C. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Levine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Molnar, L.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, H.; Zhang, S.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.

    2009-03-01

    Identified charged-particle spectra of π±, K±, p, and pmacr at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at sNN=200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close