WorldWideScience

Sample records for antihyperons

  1. Chemical equilibration of antihyperons

    International Nuclear Information System (INIS)

    Greiner, C.

    2002-01-01

    Rapid chemical equilibration of antihyperons by means of the interplay between strong annihilation on baryons and the corresponding backreactions of multi-mesonic (fusion-type) processes in the later, hadronic stage of an ultrarelativistic heavy ion collision will be discussed. Explicit rate calculations for a dynamical setup are presented. At maximum SPS energies yields of each antihyperon specie are obtained which are consistent with chemical saturated populations of T∼150-160 MeV. The proposed picture supports dynamically the popular chemical freeze-out parameters extracted within thermal models. (orig.)

  2. Heavy Hyperon-Antihyperon Production

    CERN Document Server

    Oelert, W.; Jarczyk, Lucjan; Kilian, K.; Moskal, P.; Winter, P.

    2005-01-01

    Based on the experience from the production of anti-Lambda Lambda and anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi and anti-Omega Omega in view of: (1) the production dynamics of the heavier antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the (3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson production, where both systems have similar masses (3.345 and 3.057, respectively) and identical valence quark content. A systematic study of the antihyperon--hyperon production with increasing strangeness content is interesting for the following reasons: The anti-Omega Omega production is the creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles. Results of the PS185 experiments prove a clear dominance of the spin triplet anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s quarks) are aligned to spin 3/2 each. I...

  3. Studying the potential of antihyperons in nuclei with antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Lorente, Alicia; Bleser, Sebastian; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Pochodzalla, Josef [Institute for nuclear physics, JGU Mainz (Germany); Collaboration: PANDA-Collaboration

    2014-07-01

    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 + {sup 20}Ne → 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.

  4. Exploring antihyperons potentials in nuclei by antiproton-nucleon reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Lorente, Alicia [Helmholtz Institut Mainz (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    The exclusive production of hyperon-Antihyperon pairs close to their production threshold in antiproton-nucleus collisions offers a unique and hitherto unexplored opportunity to study the behaviour of Antihyperons in nuclei. For the first time we analyse these reactions in a microscopic transport model using the Giessen Boltzmann-Uehling-Uhlenbeck Transportmodel (GiBUU). We find a substantial sensitivity of transverse momentum correlations of coincident AntiLambda-Lambda-pairs to the assumed depth of the AntiLambda potential. Rather than diminishing this effect, secondary scattering effects which are more pronounced at deeper AntiLambda potentials enhance this sensitivity. Because of the high cross section for this process and the simplicity of this method our results pave the way for experimental studies at the FAIR facility.

  5. Study of hyperon-antihyperon production in antiproton-proton collision at 4 GeV/c; Etude de la production d'hyperon et d'antihyperon dans les collisions antiproton-proton a 4 GeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Revel, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-05-15

    We present the results on hyperon-antihyperon production by 4 GeV/c antiprotons in hydrogen. We used about 10{sup 5} pictures taken in an antiproton beam from the CERN proton synchrotron with the 81 cm Saclay hydrogen bubble chamber. The aim of this work was the study, through the cross sections and the angular distributions, of production mechanism of hyperon antihyperon pairs and excited hyperons (or antihyperons). For most of the channels, these angular distributions show a strong forward peaking of the antihyperon in the center of mass of the interaction. This suggests that a peripheral-type mechanism is predominant in these processes. We compare the results of some cross sections, with theoretical predictions according to SU{sub 3} unitary symmetry. (author) [French] Nous presentons ici des resultats concernant la production d'hyperons et d'antihyperons dans l'interaction antiproton sur proton a 4 GeV/c. Nous avons utilise pour cette experience un lot de 10{sup 5} photographies, prises avec la chambre a bulles de 81 cm a hydrogene liquide de Saclay, placee dans un faisceau d'antiprotons aupres du synchrotron a protons du CERN. Le but de ce travail etait l'etude des mecanismes de production des paires hyperons antihyperons et des hyperons excites (antihyperons excites) au travers des sections efficaces et des distributions angulaires. Pour la plupart des voies, ces distributions angulaires, dans le systeme du centre de masse, indiquent une forte tendance a l'emission vers l'avant de l'antihyperon, ce qui suggere un mecanisme de production de type peripherique. Nous avons compare les resultats de certaines sections efficaces avec des previsions obtenues a partir de la theorie de symetrie unitaire SU{sub 3}. (auteur)

  6. Σ--antihyperon correlations in Z0 decay and investigation of the baryon production mechanism

    International Nuclear Information System (INIS)

    Abbiendi, G.; Braibant, S.; Capiluppi, P.; Ciocca, C.; Cuffiani, M.; Dallavalle, M.; Fabbri, F.; Giacomelli, G.; Giacomelli, P.; Ludwig, J.; Merritt, F.S.; Rembser, C.; Ainsley, C.; Batley, R.J.; Carter, J.R.; Hill, J.C.; Tarem, S.; Verzocchi, M.; Voss, H.; Aakesson, P.F.; Barberio, E.; Burckhart, H.J.; Roeck, A. de; Wolf, E.A. de; Ferrari, P.; Frey, A.; Gruwe, M.; Hauschild, M.; Hawkings, R.; Maettig, P.; Nanjo, H.; Pater, J.R.; Pinfold, J.; Pooth, O.; Przybycien, M.; Runge, K.; Sarkisyan, E.K.G.; Schaile, O.; Scharff-Hansen, P.; Schroeder, M.; Shen, B.C.; Strom, D.; Thomson, M.A.; Vannerem, P.; Vertesi, R.; Watkins, P.M.; Watson, A.T.; Alexander, G.; Bella, G.; Etzion, E.; Grunhaus, J.; Toya, D.; Anagnostou, G.; Bell, P.J.; Charlton, D.G.; Hawkes, C.M.; Jeremie, H.; Nakamura, I.; Trigger, I.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Wermes, N.; Anderson, K.J.; Gupta, A.; McPherson, R.A.; Neal, H.A.; Pahl, C.; Smith, A.M.; Stroehmer, R.; Asai, S.; Igo-Kemenes, P.; Junk, T.R.; Karlen, D.; Kawagoe, K.; Kluth, S.; Kobel, M.; Marcellini, S.; Mes, H.; Mikenberg, G.; Mori, T.; Mutter, A.; O'Neale, S.W.; Rozen, Y.; Teuscher, R.; Trocsanyi, Z.; Wilson, J.A.; Axen, D.; Lloyd, S.L.; Martin, A.J.; Bailey, I.; Kanzaki, J.; Kawamoto, T.; Mashimo, T.; Rabbertz, K.; Sherwood, P.; Barillari, T.; Bethke, S.; Kennedy, B.W.; Oh, A.; Plane, D.E.; Schaile, A.D.; Barlow, R.J.; Duerdoth, I.P.; Ford, M.; Kupper, M.; Lillich, J.; Orito, S.; Skuja, A.; Wengler, T.; Wilson, G.W.; Bechtle, P.; Behnke, T.; Desch, K.; Hamann, M.; Heuer, R.D.; Komamiya, S.; Krogh, J. von; McKenna, J.; Menges, W.; Bell, K.W.; Brown, R.M.; Kellogg, R.G.; Bellerive, A.; Carnegie, R.K.; Jovanovic, P.; Krasznahorkay, A.; Meijers, F.; Rossi, A.M.; Benelli, G.; Campana, S.; Gary, J.W.; Giunta, M.; Hanson, G.G.; Oreglia, M.J.; Schumacher, M.; Wolf, G.; Biebel, O.; Boutemeur, M.; Dubbert, J.; Duckeck, G.; Fiedler, F.; Sachs, K.; Saeki, T.; Spano, F.; Turner-Watson, M.F.; Boeriu, O.; Fleck, I.; Herten, G.; Letts, J.; Lu, J.; Mihara, S.; Miller, D.J.; Roney, J.M.; Ueda, I.; Bock, P.; Krieger, P.; Wells, P.S.; Carter, A.A.; Levinson, L.; Mader, W.; Mohr, W.; Chang, C.Y.; Keeler, R.K.; Shears, T.G.; Vollmer, C.F.; Csilling, A.; Hajdu, C.; Horvath, D.; Dado, S.; Goldberg, J.; Harel, A.; Lafferty, G.D.; Renkel, P.; Stahl, A.; Wyatt, T.R.; Dienes, B.; Kraemer, T.; Torrence, E.; Tsur, E.; Ujvari, B.; Duchovni, E.; Gross, E.; Kuhl, T.; Lanske, D.; Lellouch, D.; Meyer, N.; Quadt, A.; Wetterling, D.; Gagnon, P.; Geich-Gimbel, C.; Kobayashi, T.; Loebinger, F.K.; Ludwig, A.; Schieck, J.; Watson, N.K.; Ishii, K.; Landsman, H.; Pilcher, J.E.; Schoerner-Sadenius, T.; Sobie, R.; Michelini, A.; Seuster, R.; Nagai, K.; Pasztor, G.; Soeldner-Rembold, S.; Tasevsky, M.

    2009-01-01

    Data collected around √(s)=91 GeV by the OPAL experiment at the LEP e + e - collider are used to study the mechanism of baryon formation. As the signature, the fraction of Σ - hyperons whose baryon number is compensated by the production of a anti Σ - , anti Λ or anti Ξ - antihyperon is determined. The method relies entirely on quantum number correlations of the baryons, and not rapidity correlations, making it more model independent than previous studies. Within the context of the JETSET implementation of the string hadronization model, the diquark baryon production model without the popcorn mechanism is strongly disfavored with a significance of 3.8 standard deviations including systematic uncertainties. It is shown that previous studies of the popcorn mechanism with Λanti Λ and p anti p correlations are not conclusive, if parameter uncertainties are considered. (orig.)

  7. Study of $\\Sigma$(1385) and $\\Xi$(1321) hyperon and antihyperon production in deep inelastic muon scattering

    CERN Document Server

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

    2013-01-01

    Large samples of $\\Lambda$, $\\Sigma(1385)$ and $\\Xi(1321)$ hyperons produced in deep-inelastic muon scattering off a $^6$LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of $\\Sigma(1385)^+$, $\\Sigma(1385)^-$, $\\bar{\\Sigma}(1385)^-$, $\\bar{\\Sigma}(1385)^+$, $\\Xi(1321)^-$, and $\\bar{\\Xi}(1321)^+$ hyperons decaying into $\\Lambda(\\bar{\\Lambda})\\pi$ were measured. The heavy hyperon to $\\Lambda$ and heavy antihyperon to $\\bar{\\Lambda}$ yield ratios were found to be in the range 3.8% to 5.6% with a relative uncertainty of about 10%. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.

  8. Study of {Sigma}(1385) and {Xi}(1321) hyperon and antihyperon production in deep inelastic muon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Adolph, C.; Braun, C.; Eyrich, W.; Lehmann, A.; Schmidt, A. [Universitaet Erlangen-Nuernberg, Physikalisches Institut, Erlangen (Germany); Alekseev, M.G.; Birsa, R.; Bravar, A.; Dalla Torre, S.; Dasgupta, S.S.; Gobbo, B.; Sozzi, F.; Steiger, L.; Tessaro, S.; Tessarotto, F. [Trieste Section of INFN, Trieste (Italy); Alexakhin, V.Y.; Alexeev, G.D.; Efremov, A.; Gavrichtchouk, O.P.; Gushterski, R.; Guskov, A.; Ivanshin, Y.; Kroumchtein, Z.V.; Kuchinski, N.; Meshcheryakov, G.; Nagaytsev, A.; Olshevsky, A.G.; Rodionov, V.; Rossiyskaya, N.S.; Sapozhnikov, M.G.; Savin, I.A.; Shevchenko, O.Y.; Zemlyanichkina, E.; Zhuravlev, N. [Joint Institute for Nuclear Research, Dubna, Moscow region (Russian Federation); Alexandrov, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Amoroso, A.; Balestra, F.; Bertini, R.; Chiosso, M.; Garfagnini, R.; Gnesi, I.; Grasso, A.; Kotzinian, A.M.; Parsamyan, B.; Piragino, G.; Sosio, S. [University of Turin, Department of Physics (Italy); Torino Section of INFN, Turin (Italy); Austregesilo, A.; Bicker, K. [CERN, Geneva 23 (Switzerland); Technische Universitaet Muenchen, Physik Department, Garching (Germany); Badelek, B. [University of Warsaw, Faculty of Physics, Warsaw (Poland); Barth, J.; Bieling, J.; Goertz, S.; Klein, F.; Panknin, R.; Pretz, J.; Windmolders, R. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Baum, G. [Universitaet Bielefeld, Fakultaet fuer Physik, Bielefeld (Germany); Bedfer, Y.; Burtin, E.; Capozza, L.; Ferrero, A.; Hose, N. d' ; Kunne, F.; Magnon, A.; Marchand, C.; Morreale, A.; Neyret, D.; Platchkov, S.; Thibaud, F.; Vandenbroucke, M.; Wollny, H. [CEA IRFU/SPhN Saclay, Gif-sur-Yvette (France); Berlin, A.; Gautheron, F.; Hess, C.; Kisselev, Y.; Koivuniemi, J.H.; Meyer, W.; Reicherz, G.; Wang, L. [Universitaet Bochum, Institut fuer Experimentalphysik, Bochum (Germany); Bernhard, J.; Harrach, D. von; Jasinski, P.; Kabuss, E.; Kang, D.; Ostrick, M.; Pochodzalla, J.; Weisrock, T.; Wilfert, M. [Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany); Bisplinghoff, J.; Eversheim, P.D.; Hinterberger, F.; Jahn, R.; Joosten, R.; Schmiden, H. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bordalo, P.; Franco, C.; Nunes, A.S.; Quaresma, M.; Quintans, C.; Ramos, S.; Silva, L.; Stolarski, M. [LIP, Lisbon (Portugal); Bradamante, F.; Bressan, A.; Duic, V.; Elia, C.; Giorgi, M.; Levorato, S.; Martin, A.; Sbrizzai, G.; Schiavon, P. [University of Trieste, Department of Physics (Italy); Trieste Section of INFN, Trieste (Italy); Buechele, M.; Fischer, H.; Guthoerl, T.; Heinsius, F.H.; Herrmann, F.; Koenigsmann, K.; Nerling, F.; Nowak, W.D.; Schill, C.; Schmidt, K.; Schopferer, S.; Sirtl, S.; Wolbeek, J. ter [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Chung, S.U.; Friedrich, J.M.; Grabmueller, S.; Grube, B.; Haas, F.; Hoeppner, C.; Huber, S.; Ketzer, B.; Kraemer, M.; Mann, A.; Nagel, T.; Neubert, S.; Paul, S.; Schmitt, L.; Uhl, S. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Cicuttin, A.; Crespo, M.L. [Abdus Salam ICTP, Trieste (Italy); Trieste Section of INFN, Trieste (Italy); Dasgupta, S.; Sarkar, S.; Sinha, L. [Matrivani Institute of Experimental Research and Education, Calcutta (India); Denisov, O.Y.; Maggiora, A.; Takekawa, S. [Torino Section of INFN, Turin (Italy); Donskov, S.V.; Filin, A.; Khaustov, G.V.; Khokhlov, Y.A.; Kolosov, V.N.; Konstantinov, V.F.; Lednev, A.A.; Mikhailov, Yu.V.; Nikolaenko, V.I.; Polyakov, V.A.; Ryabchikov, D.I.; Samoylenko, V.D. [State Research Center of the Russian Federation, Institute for High Energy Physics, Protvino (Russian Federation); Doshita, N.; Ishimoto, S.; Iwata, T.; Kondo, K.; Matsuda, H.; Michigami, T.; Miyachi, Y.; Suzuki, H. [Yamagata University, Yamagata (Japan); Duennweber, W.; Faessler, M.; Geyer, R.; Schlueter, T.; Uman, I. [Ludwig-Maximilians-Universitaet Muenchen, Department fuer Physik, Munich (Germany); Dziewiecki, M.; Kurjata, R.P.; Marzec, J.; Zaremba, K.; Ziembicki, M. [Warsaw University of Technology, Institute of Radioelectronics, Warsaw (Poland); Finger, M.; Finger, M.; Novy, J. [Charles University in Prague, Faculty of Mathematics and Physics, Prague (Czech Republic); Du Fresne von Hohenesche, N. [CERN, Geneva 23 (Switzerland); Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany); Frolov, V.; Mallot, G.K.; Rocco, E.; Schoenning, K.; Schott, M. [CERN, Geneva 23 (Switzerland); Gerassimov, S.; Konorov, I. [Lebedev Physical Institute, Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department, Garching (Germany); Horikawa, N. [Nagoya University, Nagoya (Japan); Jary, V.; Virius, M. [Czech Technical University in Prague, Prague (Czech Republic); Klimaszewski, K.; Kurek, K.; Rondio, E.; Sandacz, A.; Sulej, R.; Sznajder, P.; Wislicki, W. [National Centre for Nuclear Research, Warsaw (Poland); Kouznetsov, O. [Joint Institute for Nuclear Research, Dubna, Moscow region (Russian Federation); CEA IRFU/SPhN Saclay, Gif-sur-Yvette (France); Lichtenstadt, J. [Tel Aviv University, School of Physics and Astronomy, Tel Aviv (Israel); Makke, N. [CEA IRFU/SPhN Saclay, Gif-sur-Yvette (France); University of Trieste, Department of Physics (IT); Trieste Section of INFN, Trieste (IT); Matsuda, T. [University of Miyazaki, Miyazaki (JP); Panzieri, D. [University of Eastern Piedmont, Alessandria (IT); Polak, J. [Technical University in Liberec, Liberec (CZ); University of Trieste, Department of Physics (IT); Trieste Section of INFN, Trieste (IT); Srnka, A. [AS CR, Institute of Scientific Instruments, Brno (CZ); Sulc, M. [Technical University in Liberec, Liberec (CZ); Zavertyaev, M. [Lebedev Physical Institute, Moscow (RU)

    2013-10-15

    Large samples of {Lambda}, {Sigma}(1385) and {Xi}(1321) hyperons produced in the deep-inelastic muon scattering off a {sup 6}LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of {Sigma}(1385){sup +}, {Sigma}(1385){sup -}, anti {Sigma}(1385){sup -}, anti {Sigma}(1385){sup +}, {Xi}(1321){sup -}, and anti {Xi}(1321){sup +} hyperons decaying into {Lambda}(anti {Lambda}){pi} were measured. The ratios of heavy-hyperon to {Lambda} and heavy-antihyperon to anti {Lambda} were found to be in the range 3.8 % to 5.6 % with a relative uncertainty of about 10 %. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator. (orig.)

  9. Study of Σ(1385) and Ξ(1321) hyperon and antihyperon production in deep inelastic muon scattering

    International Nuclear Information System (INIS)

    Adolph, C.; Braun, C.; Eyrich, W.; Lehmann, A.; Schmidt, A.; Alekseev, M.G.; Birsa, R.; Bravar, A.; Dalla Torre, S.; Dasgupta, S.S.; Gobbo, B.; Sozzi, F.; Steiger, L.; Tessaro, S.; Tessarotto, F.; Alexakhin, V.Y.; Alexeev, G.D.; Efremov, A.; Gavrichtchouk, O.P.; Gushterski, R.; Guskov, A.; Ivanshin, Y.; Kroumchtein, Z.V.; Kuchinski, N.; Meshcheryakov, G.; Nagaytsev, A.; Olshevsky, A.G.; Rodionov, V.; Rossiyskaya, N.S.; Sapozhnikov, M.G.; Savin, I.A.; Shevchenko, O.Y.; Zemlyanichkina, E.; Zhuravlev, N.; Alexandrov, Y.; Amoroso, A.; Balestra, F.; Bertini, R.; Chiosso, M.; Garfagnini, R.; Gnesi, I.; Grasso, A.; Kotzinian, A.M.; Parsamyan, B.; Piragino, G.; Sosio, S.; Austregesilo, A.; Bicker, K.; Badelek, B.; Barth, J.; Bieling, J.; Goertz, S.; Klein, F.; Panknin, R.; Pretz, J.; Windmolders, R.; Baum, G.; Bedfer, Y.; Burtin, E.; Capozza, L.; Ferrero, A.; Hose, N. d'; Kunne, F.; Magnon, A.; Marchand, C.; Morreale, A.; Neyret, D.; Platchkov, S.; Thibaud, F.; Vandenbroucke, M.; Wollny, H.; Berlin, A.; Gautheron, F.; Hess, C.; Kisselev, Y.; Koivuniemi, J.H.; Meyer, W.; Reicherz, G.; Wang, L.; Bernhard, J.; Harrach, D. von; Jasinski, P.; Kabuss, E.; Kang, D.; Ostrick, M.; Pochodzalla, J.; Weisrock, T.; Wilfert, M.; Bisplinghoff, J.; Eversheim, P.D.; Hinterberger, F.; Jahn, R.; Joosten, R.; Schmiden, H.; Bordalo, P.; Franco, C.; Nunes, A.S.; Quaresma, M.; Quintans, C.; Ramos, S.; Silva, L.; Stolarski, M.; Bradamante, F.; Bressan, A.; Duic, V.; Elia, C.; Giorgi, M.; Levorato, S.; Martin, A.; Sbrizzai, G.; Schiavon, P.; Buechele, M.; Fischer, H.; Guthoerl, T.; Heinsius, F.H.; Herrmann, F.; Koenigsmann, K.; Nerling, F.; Nowak, W.D.; Schill, C.; Schmidt, K.; Schopferer, S.; Sirtl, S.; Wolbeek, J. ter; Chung, S.U.; Friedrich, J.M.; Grabmueller, S.; Grube, B.; Haas, F.; Hoeppner, C.; Huber, S.; Ketzer, B.; Kraemer, M.; Mann, A.; Nagel, T.; Neubert, S.; Paul, S.; Schmitt, L.; Uhl, S.; Cicuttin, A.; Crespo, M.L.; Dasgupta, S.; Sarkar, S.; Sinha, L.; Denisov, O.Y.; Maggiora, A.; Takekawa, S.; Donskov, S.V.; Filin, A.; Khaustov, G.V.; Khokhlov, Y.A.; Kolosov, V.N.; Konstantinov, V.F.; Lednev, A.A.; Mikhailov, Yu.V.; Nikolaenko, V.I.; Polyakov, V.A.; Ryabchikov, D.I.; Samoylenko, V.D.; Doshita, N.; Ishimoto, S.; Iwata, T.; Kondo, K.; Matsuda, H.; Michigami, T.; Miyachi, Y.; Suzuki, H.; Duennweber, W.; Faessler, M.; Geyer, R.; Schlueter, T.; Uman, I.; Dziewiecki, M.; Kurjata, R.P.; Marzec, J.; Zaremba, K.; Ziembicki, M.; Finger, M.; Finger, M.; Novy, J.; Du Fresne von Hohenesche, N.; Frolov, V.; Mallot, G.K.; Rocco, E.; Schoenning, K.; Schott, M.; Gerassimov, S.; Konorov, I.; Horikawa, N.; Jary, V.; Virius, M.; Klimaszewski, K.; Kurek, K.; Rondio, E.; Sandacz, A.; Sulej, R.; Sznajder, P.; Wislicki, W.; Kouznetsov, O.; Lichtenstadt, J.; Makke, N.; Matsuda, T.; Panzieri, D.; Polak, J.; Srnka, A.; Sulc, M.; Zavertyaev, M.

    2013-01-01

    Large samples of Λ, Σ(1385) and Ξ(1321) hyperons produced in the deep-inelastic muon scattering off a 6 LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of Σ(1385) + , Σ(1385) - , anti Σ(1385) - , anti Σ(1385) + , Ξ(1321) - , and anti Ξ(1321) + hyperons decaying into Λ(anti Λ)π were measured. The ratios of heavy-hyperon to Λ and heavy-antihyperon to anti Λ were found to be in the range 3.8 % to 5.6 % with a relative uncertainty of about 10 %. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator. (orig.)

  10. Antihyperon-hyperon production in antiproton-proton annihilations with PANDA at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Papenbrock, Michael [Department of Nuclear Physics and Astronomy, Uppsala University, Uppsala (Sweden); Collaboration: PANDA-Collaboration

    2015-07-01

    The production of antihyperon-hyperon pairs in antiproton-proton annihilations involves the annihilation of at least one light (u,d) quark-antiquark pair and the creation of a heavier (s,c,b) pair. Production of strange hyperons occur in an energy region in which QCD is difficult to predict. By studying hyperon production we learn about the strong interaction in this energy region, i.e. the confinement domain. It is an open question what the relevant degrees of freedom are: quarks and gluons, or hadrons. Spin observables is an excellent tool in order to better understand the physical processes. These are accessible via the weak, parity violating decay of the hyperon which results in an angular asymmetry of the decay products. The future PANDA experiment at FAIR is going to be ideally suited to study spin physics on hyperons with both high precision and high statistics. Since hyperons decay weakly and thus have long life-times, their decay vertices are displaced with respect to the production point. This sets high demands on precise track reconstruction. A pattern recognition algorithm is currently under development, with the ability to reconstruct tracks originating in displaced vertices. Simulation studies done by the Uppsala group as well as the status of the development will be presented and discussed.

  11. Antihyperon-hyperon production in the meson exchange framework

    International Nuclear Information System (INIS)

    Haidenbauer, J.; Holinde, K.; Speth, J.

    1992-01-01

    Strangeness production processes bar pp→ bar YY (Y=Λ,Σ) have been studied near threshold in a full coupled-channel calculation. The transition interactions are based on K- and K * -meson exchange. The elastic part of the bar pp and bar YY interactions has been derived from a one-boson-exchange version of the Bonn NN potential and a corresponding extension to the hyperon-nucleon case whereas the annihilation part is taken into account by introducing phenomenological optical potentials. First results are presented for the reactions bar pp→ bar ΛΣ 0 +bar Σ 0 Λ as well as bar pp→ bar Σ ± Σ ± , bar Σ 0 Σ 0 , which agree with existing data. As in bar pp→ bar ΛΛ, tensor and spin-triplet dominance is realized in bar pp→ bar Σ Σ but is somewhat reduced in bar pp→ bar Λ Σ 0 +bar Σ 0 Λ. Although bar Σ - Σ - cannot be reached from bar pp by a single transition, the corresponding cross section is only slightly smaller than for bar Σ + Σ + . Initial-and final-state effects play a decisive role, even in cross section ratios

  12. Study of Sigma(1385) and Xi(1321) hyperon and antihyperon production in deep inelastic muon scattering

    Czech Academy of Sciences Publication Activity Database

    Adolph, C.; Alekseev, M.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Austregisilio, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bertini, R.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Donskov, S.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.V.; Elia, C.; Eversheim, P.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmüller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthörl, T.; Haas, F.; von Harrach, D.; Heinsius, F.; Herrmann, F.; Hess, C.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joosten, R.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.; Kolosov, V.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.; Kotzinian, A.; Kouznetsov, O.; Krämer, M.; Kroumchtein, Z.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.; Mann, A.; Marchand, C.; Martin, A.; Marzec, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Y.; Miyachi, Y.; Morreale, A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Reicherz, G.; Rocco, E.; Rodionov, V. K.; Rondio, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Samoylenko, V.; Sandacz, A.; Sapozhnikov, M.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlütter, T.; Schmidt, A.; Schmidt, K.; Schmiden, H.; Schmitt, L.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.; Silva, L.; Sinha, L.; Sirtl, S.; Sosio, S.; Sozzi, F.; Srnka, Aleš; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

    2013-01-01

    Roč. 73, č. 10 (2013), 2581:1-9 ISSN 1434-6044 Institutional support: RVO:68081731 Keywords : charged current interactions * nomad experiment * (lambda) over-bar polarization * compass Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 5.436, year: 2013

  13. Recent results on (anti)nucleus and (anti)hyperon production in nucleus-nucleus collisions at CERN SPS energies

    CERN Document Server

    Melkumov, G L; Anticic, T; Baatar, B; Barna, D; Bartke, J; Betev, L; Bialkowska, H; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chung, P; Chvala, O; Cramer, J G; Csató, P; Dinkelaker, P; Eckardt, V; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gál, J; Gazdzicki, M; Genchev, V; Georgopoulos, G; Grebieszkow, K; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kikola, D; Gladysz-Dziadus, E; Kliemant, M; Kniege, S; Kolesnikov, V I; Kornas, E; Korus, R; Kowalski, M; Kraus, I; Kreps, M; Laszlo, A; Lacey, R; Van Leeuwen, M; Lvai, P; Litov, L; Lungwitz, B; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mischke, A; Mitrovski, M; Molnár, J; Mrówczynski, S; Nicolic, V; Pálla, G; Panagiotou, A D; Panayotov, D; Petridis, A; Peryt, W; Pikna, M; Pluta, J; Prindle, D; Pühlhofer, F; Renfordt, R; Roland, C; Roland5, G; Rybczynski, M; Rybicki, A; Sandoval, A; Schmitz, N; Schuster, T; Siklér, F; Sitár, B; Skrzypczak, E; Slodkowski, M; Stefanek, G; Stock, R; Seyboth, P; Strabel, C; Ströbele, H; Susa, T; Szentpetery, I; Sziklai, J; Szuba, M; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranic, D; Wlodarczyk, Z; Wojtaszek11, A; Yoo, I K; Zimnyi, J; Wetzler, A

    2007-01-01

    The NA49 experiment has collected comprehensive data on particle production in nucleus-nucleus collisions over the whole SPS beam energies range, the critical energy domain where the expected phase transition to a deconfined phase is expected to occur. The latest results from Pb+Pb collisions between 20$A$ GeV and 158$A$ GeV on baryon stopping and light nuclei production as well as those for strange hyperons are presented. The measured data on $p$, $\\bar{p}$, $\\Lambda$, $\\bar{\\Lambda}$, $\\Xi^-$ and $\\bar{\\Xi}^+$ production were used to evaluate the rapidity distributions of net-baryons at SPS energies and to compare with the results from the AGS and the RHIC for central Pb+Pb (Au+Au) collisions. The dependence of the yield ratios and the inverse slope parameter of the $m_t$ spectra on the collision energy and centrality, and the mass number of the produced nuclei $^3He$, $t$, $d$ and $\\bar{d}$ are discussed within coalescence and statistical approaches. Analysis of the total multiplicity exhibits remarkable a...

  14. WA97 results on strangeness production in lead lead collisions at 158 A GeV/c

    Czech Academy of Sciences Publication Activity Database

    Andersen, E.; Andrighetto, A.; Antinori, F.; Böhm, Jan; Píška, Karel; Staroba, Pavel; Šťastný, Jan; Vaníčková, Marcela; Závada, Petr

    1996-01-01

    Roč. 610, - (1996), 165c-174c ISSN 0375-9474 R&D Projects: GA ČR GA202/95/0217 Keywords : hyperon * antihyperon production * yield (Lambda Antilambda) * yield (Omega- Xi-) * mass spectrum * CERN SPS * 158 GeV/c/nucleon Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.825, year: 1996

  15. Enhancement of hyperon production at central rapidity in 158 A GeV/c Pb-Pb collisions

    Czech Academy of Sciences Publication Activity Database

    Antinori, F.; Bacon, P.; Balada, A.; Staroba, Pavel; Závada, Petr

    2006-01-01

    Roč. 32, - (2006), s. 427-441 ISSN 0954-3899 Institutional research plan: CEZ:AV0Z10100502 Keywords : central Pb-Pb * hyperon * antihyperon * yield * rapidity * transverse momentum Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.781, year: 2006

  16. Experimental medium energy physics

    International Nuclear Information System (INIS)

    1989-01-01

    This report discusses the following topics: search for the ξ(2230) at LEAR; hyperon-antihyperon production studies at LEAR; relativistic proton-nucleus and heavy ion-nucleus collisions at the SPS; search for the H dibaryon at the AGS; hypernuclear physics research; CEBAF activities; pion physics at PSI; and H particle experiment design and development

  17. Strangeness production with antiprotons

    International Nuclear Information System (INIS)

    Barnes, P.D.; Maher, C.J.

    1986-05-01

    New data from LEAR on the production of hyperon-antihyperon pairs in strong interactions is reported. The possibility of checking CP invariance in the anti ΛΛ system is reviewed together with plans to search for the ξ(2230) in the rho + anti rho → K/sub s/ + anti K/sub s/ reaction. 21 refs., 9 figs., 1 tab

  18. Experimental medium energy physics

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1990-01-01

    This report discusses the following topics: search for the H-dibaryon at the AGS; weak interaction studies with hypernuclear decays at the AGS; search for the ξ(2230) at LEAR; relativistic proton-nucleus and heavy ion-nucleus collisions at the SPS; hyperon-antihyperon production studies at LEAR; photoproduction of strange CEBAF; and experiment design development

  19. Mass determination of Λ 0 and anti-Λ0 produced by pp reactions

    International Nuclear Information System (INIS)

    Buenrostro C, E.A.; Quintero G, G.I.; Felix, J.

    1997-01-01

    It was determined the mass of the hyperon Λ 0 and of the anti-hyperon anti-Λ 0 , during the second scientific research summer. Both hyperons were collected from inclusive and exclusive proton-proton collisions. The results are in excellent agreement with the universally accepted values. In this paper we compare both values and discuss their theoretical consequences. (Author)

  20. Experimental medium energy physics: Annual progress report June 1987--May 1988

    International Nuclear Information System (INIS)

    1988-01-01

    This report discusses progress in experimental medium energy physics at Carnegie Mellon University. Some of the topics covered are: search for the ξ(2230); hyperon-antihyperon production studies; relativistic proton-nucleus and heavy ion-nucleus collisions; H dibaryon physics; hypernuclear physics research; pion physics; H particle experiment design and development; and electron scattering

  1. Experimental medium energy physics

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1991-01-01

    This report discusses the following topics: Search for the H Dibaryon at the AGS; Hypernuclear Weak Decay Studies at the AGS; Relativistic Proton-Nucleus and Heavy Ion-Nucleus Collisions at the SPS; Hyperon-Antihyperon Production studies at LEAR; Hyperon Photoproduction at CEBAF; Double Lambda Hypernuclei; Weak Decay of Light Hypernuclei; and π 0 /γDetection with the CMU Scintillator Arrays

  2. Lambda-antilambda decay asymmetries and CP violation

    International Nuclear Information System (INIS)

    Hertzog, D.W.; Barnes, P.D.; Birien, P.

    1988-01-01

    The exclusive reaction /bar p/p → /bar Lambda/Λ is an interesting laboratory in which to study both spin physics and fundamental symmetries. The PS185 collaboration at LEAR has been exploiting this fact for the last few years in an ongoing program of hyperon-antihyperon production. The motivation for this study will be outlined and the experimental technique will be described. Spin physics aspects such as the measurements of the outgoing hyperon polarization and preliminary determinations of spin correlation coefficients will be presented. Fundamental symmetry checks such as lifetime differences between Λ and /bar Lambda/ (CPT) and decay properties (CP) will be discussed. A future experiment which is quite sensitive to CP violation in a hyperon-antihyperon system will be mentioned. 15 refs., 4 figs

  3. Study of Threshold Production of $\\overline{p}p \\rightarrow \\overline{Y}Y$ at LEAR

    CERN Multimedia

    2002-01-01

    Y bar Y $. The channels $ \\bar{\\Lambda} \\Lambda $, $ \\bar{\\Lambda} Sigma ^0 $+c.c., $ Sigma bar sup + Sigma sup + $ and $ Sigma bar sup - Sigma sup - $ are studied. Our aim is to determine quantum numbers of the strange-antistrange quark pair creation which is embedded in these different $ Y bar Y $ channels. In addition, total and differential cross-sections for $\\bar{p}$p$\\rightarrow$ $ K _{s} K _{s} $ are measured.\\\\ \\\\ The data allow for a comparison of decay-asymmetry parameters, partial decay branching ratios and lifetimes of hyperon and antihyperon non-leptonic decays, which can provide tests of fundamental symmetries CP and CPT, respectively. We study also aspects of low-energy $ Y bar Y $ final-state interactions. We can obtain information on hyperon and antihyperon scattering on protons and carbon, including the spin dependence of the cross-section. \\\\ \\\\ The signature of delayed hyperon decays Y$\\rightarrow$N$\\pi$ (or $ K _{s} $ $\\rightarrow

  4. Hyperon production in Pb + Pb collisions at 158 A GeV/c

    Czech Academy of Sciences Publication Activity Database

    Andersen, E.; Andrighetto, A.; Antinori, F.; Böhm, Jan; Píška, Karel; Staroba, Pavel; Šťastný, Jan; Vaníčková, Marcela; Závada, Petr

    1996-01-01

    Roč. 4, - (1996), s. 97-103 ISSN 1219-7580. [Workshop on strangeness in Hadronic Matter ( Strangeness 96). Budapest, 15.05.1996-17.05.1996] R&D Projects: GA ČR GA202/95/0217 Keywords : heavy ion collision * lead-lead * hyperon * antihyperon production * yield * (Omega- Xi- Lambda) * enhancement * (Omega- Xi-) * mass spectrum * magnetic spectrometer * OMEGA * CERN SPS * 158 GeV/c/nucleon Subject RIV: BF - Elementary Particles and High Energy Physics

  5. Baryon-antibaryon dynamics in relativistic heavy-ion collisions

    Science.gov (United States)

    Seifert, E.; Cassing, W.

    2018-04-01

    The dynamics of baryon-antibaryon annihilation and reproduction (B B ¯↔3 M ) is studied within the Parton-Hadron-String Dynamics (PHSD) transport approach for Pb+Pb and Au+Au collisions as a function of centrality from lower Super Proton Synchrotron (SPS) up to Large Hadron Collider (LHC) energies on the basis of the quark rearrangement model. At Relativistic Heavy-Ion Collider (RHIC) energies we find a small net reduction of baryon-antibaryon (B B ¯ ) pairs while for the LHC energy of √{sN N}=2.76 TeV a small net enhancement is found relative to calculations without annihilation (and reproduction) channels. Accordingly, the sizable difference between data and statistical calculations in Pb+Pb collisions at √{sN N}=2.76 TeV for proton and antiproton yields [ALICE Collaboration, B. Abelev et al., Phys. Rev. C 88, 044910 (2013), 10.1103/PhysRevC.88.044910], where a deviation of 2.7 σ was claimed by the ALICE Collaboration, should not be attributed to a net antiproton annihilation. This is in line with the observation that no substantial deviation between the data and statistical hadronization model (SHM) calculations is seen for antihyperons, since according to the PHSD analysis the antihyperons should be modified by the same amount as antiprotons. As the PHSD results for particle ratios are in line with the ALICE data (within error bars) this might point towards a deviation from statistical equilibrium in the hadronization (at least for protons and antiprotons). Furthermore, we find that the B B ¯↔3 M reactions are more effective at lower SPS energies where a net suppression for antiprotons and antihyperons up to a factor of 2-2.5 can be extracted from the PHSD calculations for central Au+Au collisions.

  6. 1-4 Strangeness Production in Antiproton Induced Nuclear Reactions.

    Institute of Scientific and Technical Information of China (English)

    Feng; Zhaoqing[1

    2014-01-01

    More localized energy deposition is able to be produced in antiproton-nucleus collisions in comparison withheavy-ion collisions due to annihilation reactions. Searching for the cold quark-gluon plasma (QGP) with antiprotonbeamshas been considered as a hot topic both in experiments and in theretical calculations over the past severaldecades. Strangeness production and hypernucleus formation in antiproton-induced nuclear reactions are importancein exploring the hyperon (antihyperon)-nucleon (HN) potential and the antinucleon-nucleon interaction, whichhave been hot topics in the forthcoming experiments at PANDA in Germany.

  7. CP violation in hyperon decays: the case p-bar p → Λ-bar Λ → p-bar π+ pπ-

    International Nuclear Information System (INIS)

    Hamann, N.; He, X.G.; Landua, R.; Ohlsson, S.; Steger, H.; Valencia, G.; Fischer, H.; Geyer, R.; Hertzog, D.; Kolo, B.; Miller, J.P.; Rohrich, K.

    1992-01-01

    An account is given of the experimental status of CP violation and of the phenomenology of hyperon non-leptonic decays. Updated information on the estimate of CP-violating observable in these decays is presented. An experimental programme is outlined, which aims to pursue the search for direct CP violation in hyperon-antihyperon decays by means of the reaction p-bar p → Λ-bar Λ → p-bar π + pπ - . The experiment as well as analysis methods are described. Alternative approaches employing hyperons are also discussed. 54 refs., 1 tab., 13 figs

  8. Estudo da Polarizacao dos Hiperons $\\Xi^-$ E $\\Omega^-$

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho De Gouvea, Andre Luiz [Pontifical Catholic Univ., Rio de Janeiro (Brazil)

    1995-01-01

    ln this thesis the polarization of the $\\Xi^-$ hyperon and the $\\Xi^+$ antihyperon produced in the Fermilab Experiment E791 was determined by the analysis of the weak decay $\\Xi^- \\to \\Lambda^0 + \\pi^-$. For $\\Xi^-$ produced in the interaction between a 500 GeV/c $\\pi^-$ beam and a unpolarized carbon (platinum) target in the region $p_t$ > 0.8 GeV/c and $X_F$ > 0, -10.9% ± 1.5% (-14.7% ± 3.1%) polarization was obtained perpendicular to the production plane and -5.92% ± 1.69% (-2.41%±3.53% $\\approx O$) polarization was measured for $\\Xi^+$. Evidence was also found for a polarized $\\Omega^-$ hyperon produced in the same experiment in the region $X_F$ >0, after analysis of the weak decay $\\Omega^- \\to \\Lambda^0 + K^-$.

  9. Reconstructing Hyperons with the ANDA Detector at FAIR

    International Nuclear Information System (INIS)

    Ikegami Andersson, W

    2016-01-01

    Hyperon production and the study of their properties is an important part of the physics programme of the future ANDA experiment at FAIR. Antihyperon-hyperon pairs will be produced in antiproton-proton collisions through the annihilation of at least one light antiquark-quark ( u, d ) pair and the creation of a corresponding number of antiquark-quark s pairs. By measuring the decay products of the hyperons, spin observables such as the polarisation can be measured. Many hyperons have a long life-time which gives rise to final state particles originating from displaced vertices. A pattern recognition algorithm using information from the ANDA Straw Tube Tracker is extended to reconstruct not only the transversal, but also the longitudinal components of charged tracks. A Hough transform and a path finding method as tools to extract the longitudinal components are being developed. (paper)

  10. HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

    International Nuclear Information System (INIS)

    Burnstein, R.A.; Chakravorty, A.; Chan, A.; Chen, Y.C.; Choong, W.-S.; Clark, K.; Dukes, E.C.; Durandet, C.; Felix, J.; Fuzesy, R.; Gidal, G.; Gu, P.; Gustafson, H.R.; Ho, C.; Holmstrom, T.; Huang, M.; James, C.; Jenkins, C.M.; Jones, T.D.; Kaplan, D.M.; Lederman, L.M.; Leros, N.; Longo, M.J.; Lopez, F.; Lu, L.C.; Luebke, W.; Luk, K.-B.; Nelson, K.S.; Park, H.K.; Perroud, J.-P.; Rajaram, D.; Rubin, H.A.; Teng, P.K.; Turko, B.; Volk, J.; White, C.G.; White, S.L.; Zyla, P.

    2005-01-01

    The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in Ξ and Λ hyperon decays with a sensitivity of 10 -4 . Intense charged secondary beams were produced by 800GeV/c protons and momentum selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in 12 months of data-taking

  11. Bell's theorem, the measurement problem, Newton's self-gravitation and its connections to violations of the discrete symmetries C, P, T

    International Nuclear Information System (INIS)

    Hiesmayr, Beatrix C

    2015-01-01

    About 50 years ago John St. Bell published his famous Bell theorem that initiated a new field in physics. This contribution discusses how discrete symmetries relate to the big open questions of quantum mechanics, in particular:(i) how correlations stronger than those predicted by theories sharing randomness (Bell's theorem) relate to the violation of the CP symmetry and the P symmetry; and its relation to the security of quantum cryptography,(ii) how the measurement problem (“why do we observe no tables in superposition?”) can be polled in weakly decaying systems,(iii) how strongly and weakly interacting quantum systems are affected by Newton's self gravitation.These presented preliminary results show that the meson-antimeson systems and the hyperon- antihyperon systems are a unique laboratory to tackle deep fundamental questions and to contribute to the understand what impact the violation of discrete symmetries has. (paper)

  12. Bell's theorem, the measurement problem, Newton's self-gravitation and its connections to violations of the discrete symmetries C, P, T

    Science.gov (United States)

    Hiesmayr, Beatrix C.

    2015-07-01

    About 50 years ago John St. Bell published his famous Bell theorem that initiated a new field in physics. This contribution discusses how discrete symmetries relate to the big open questions of quantum mechanics, in particular: (i) how correlations stronger than those predicted by theories sharing randomness (Bell's theorem) relate to the violation of the CP symmetry and the P symmetry; and its relation to the security of quantum cryptography, (ii) how the measurement problem (“why do we observe no tables in superposition?”) can be polled in weakly decaying systems, (iii) how strongly and weakly interacting quantum systems are affected by Newton's self gravitation. These presented preliminary results show that the meson-antimeson systems and the hyperon- antihyperon systems are a unique laboratory to tackle deep fundamental questions and to contribute to the understand what impact the violation of discrete symmetries has.

  13. Polarization in heavy-ion collisions: magnetic field and vorticity

    Science.gov (United States)

    Baznat, M.; Gudima, K.; Prokhorov, G.; Sorin, A.; Teryaev, O.; Zakharov, V.

    2017-12-01

    The polarization of hyperons due to axial chiral vortical effect is discussed. The effect is proportional to (strange) chemical potential and is pronounced at lower energies, contrary to that of magnetic field. The polarization of antihyperons has the same sign and larger magnitude. The emergence of vortical structures is observed in kinetic QGSM models. The hydrodynamical helicity separation receives the contribution of longitudinal velocity and vorticity implying the quadrupole structure of the latter. The transition from the quark vortical effects to baryons in confined phase may be achieved by exploring the axial charge. At the hadronic level the polarization corresponds to the cores of quantized vortices in pionic superfluid. The chiral vortical effects may be also studied in the frmework of Wigner function establishing the relation to the thermodynamical approach to polarization.

  14. 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. \\\\ \\\\

  15. Milla Baldo Ceolin (1924-2011)

    CERN Multimedia

    2012-01-01

    At the end of November the particle physics community lost one of its most inquisitive, enthusiastic and active members when Milla Baldo Ceolin, emeritus professor at the University of Padua, passed away after several months of disabling illness.   After graduating from Padua in 1952, Milla began her scientific career in research with balloon-borne nuclear emulsions exposed to cosmic rays in the high atmosphere. Using a pion beam from the Bevatron at Berkeley, in 1958 Milla and D J Prowse discovered the first antihyperon: the antilambda. At the beginning of the 1960s she decided to change detection technique and began experiments with bubble chambers at Argonne, CERN and the Institute for Theoretcial and Experimental Physics (ITEP) in Moscow to investigate selection rules and conservation laws in the kaon system with higher statistics. In the meantime, her group in Padua grew steadily, working in international collaborations. The main field of her investigations changed to neutrino physics ...

  16. The anti pp yields anti λ λ reaction near threshold

    International Nuclear Information System (INIS)

    Maher, C.J.

    1986-06-01

    Measurements of differential and integrated cross sections as well as final state polarizations for the anti p p → anti Λ Λ reaction are presented. The reaction was studied at two incident antiproton momenta (1476.5 MeV/c and 1507.5 MeV/c) corresponding to total center of mass energies of 15.5 MeV and 26.4 MeV above the reaction threshold. The trajectories of charged decay products of the anti Λ and Λ were observed in a multiwire proportional chamber and in two sets of drift chambers. The data were analyzed with a computer program which reconstructed anti p p → anti Λ Λ → anti p π + pπ - events and performed kinematic fitting. The results are compared to several recent meson exchange calculations, and a one-gluon exchange calculation. The experiment was performed at the Low Energy Antiproton Ring (LEAR) at CERN. The data presented represent the first results of the PS185 collaboration's study of the threshold production of hyperon-antihyperon states

  17. Baryon-antibaryon annihilation and reproduction in relativistic heavy-ion collisions

    Science.gov (United States)

    Seifert, E.; Cassing, W.

    2018-02-01

    The quark rearrangement model for baryon-antibaryon annihilation and reproduction (B B ¯↔3 M )—incorporated in the Parton-Hadron-String Dynamics (PHSD) transport approach—is extended to the strangeness sector. A derivation of the transition probabilities for the three-body processes is presented and a strangeness suppression factor for the invariant matrix element squared is introduced to account for the higher mass of the strange quark compared to the light up and down quarks. In simulations of the baryon-antibaryon annihilation and reformation in a box with periodic boundary conditions, we demonstrate that our numerical implementation fulfills detailed balance on a channel-by-channel basis for more than 2000 individual 2 ↔3 channels. Furthermore, we study central Pb+Pb collisions within PHSD from 11.7 A GeV to 158 A GeV and investigate the impact of the additionally implemented reaction channels in the strangeness sector. We find that the new reaction channels have a visible impact essentially only on the rapidity spectra of antibaryons. The spectra with the additional channels in the strangeness sector are closer to the experimental data than without for all antihyperons. Due to the chemical redistribution between baryons-antibaryons and mesons we find a slightly larger production of antiprotons thus moderately overestimating the available experimental data. We additionally address the question if the antibaryon spectra (with strangeness) from central heavy-ion reactions at these energies provide further information on the issue of chiral symmetry restoration and deconfinement. However, by comparing transport results with and without partonic phase as well as including and excluding effects from chiral symmetry restoration we find no convincing signals in the strange antibaryon sector for either transition due to the strong final-state interactions.

  18. Gravitational constant is likely dependent on the absolute velocity of galaxy

    Science.gov (United States)

    Chen, Shao-Guang

    quantized inconsecutive time-space-spin using momentum and turn-quantity as the coordinates drawing the momentum-turn graphics are some points with certain distance. The rest mass m _{0} is the lowest energy state advance-back neutrinos pair, when j direction have 2n nuυ _{0} or nuυ (0) , the i , k directions must have (2n-1), (2n+1) nuυ _{0} or nuυ (0) for i, j, k three directions all matching into pair to eliminate the external interaction of electric quantity q (0) in nuυ _{0}. The spatial rest mass is: (n) m _{0} = (2n-1) 2n (2n+1) m (0) = 6, 60, 210, 504, 990 and 1716 m (0) . According to the uncertainty principle n large rest mass layer is more little and at the inside layer of particle. The spatial unit charge quanta e or \\underline{e} are composed by nine one-dimensional unit charge quanta _{0}nuυnuυ (0) or nuυ _{0} (0) nuυ because of the vertical polarization at each spatial direction there is only three states: the left, the right and the middle of left-right balance. With nuυ _{0} ( _{0}nuυ), e (\\underline{e}) and (n) m _{0} ((n) \\underline{m} _{0}) to constitute the muμ antineutrino, muμ neutrino, electro e (-) , and positive electro e (+) . With neutral electron ne(0) ((0) ne) as new unit compose the elementary particles masses (n) m((n) \\underline{m}) = (2n -1) 2n (2n +1) me (\\underline{m}e). The ne(0) ((0) ne) with the rest mass of electron me (\\underline{m}e). The nuυ _{0} ( _{0}nuυ), e ( \\underline{e} ) and (n) m ( (n) \\underline{m} ) to constitute the meson piπ (0) , piπ (-) , piπ (+) , K (0) , \\underline{K} (0) , K (+) , K (-) , nucleons p, \\underline{p}, n , \\underline{n}, hyperons LambdaΛ (0) ,Sigma∑ (0) , Sigma∑ (+) ,Sigma∑ (-) , XiΞ (-) , XiΞ (0) and six anti-hyperons. These particles outside layer at least has one ({2) -1} m ( ({2) -1} \\underline{m}) = 66 me (\\underline{m}e ) of piπ mesons outside layer. The nuclear force is just the direct strong interaction between _{0}nuυ, nuυ_{0}, (0) nuυ, nuυ(0) of