WorldWideScience

Sample records for antibaryons

  1. Antibaryon Photoproduction using CLAS at Jefferson Lab

    Science.gov (United States)

    Phelps, William; CLAS Collaboration

    2017-09-01

    There is little known about the baryon-antibaryon photoproduction mechanism. Three reactions, γp -> pp p , γp -> pp n π- , and γp -> pn p π+ have been investigated for the photon energy range of 3.95-5.45 GeV. The data were from the g12 experiment taken with the CLAS detector using a liquid hydrogen target in Hall B at Thomas Jefferson National Accelerator Facility. This experiment had high statistics, with an integrated luminosity of 68 pb-1. General features of the data and preliminary cross sections for the p p system will be discussed.

  2. Unified origin for baryonic visible matter and antibaryonic dark matter.

    Science.gov (United States)

    Davoudiasl, Hooman; Morrissey, David E; Sigurdson, Kris; Tulin, Sean

    2010-11-19

    We present a novel mechanism for generating both the baryon and dark matter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable dark matter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of dark matter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

  3. Antibaryon production in AU+AU collisions at the AGS

    International Nuclear Information System (INIS)

    Heintzelman, G.A.; Back, B. B.; Betts, R. R.; Chang, J.; Chang, W. C.; Chi, C. Y.; Gillitzer, A.; Henning, W. F.; Hofman, D. J.; Nanal, V.; Wuosmaa, A. H.

    1999-01-01

    Experiment E917 at the Brookhaven AGS has made a measurement of near-mid-rapidity antibaryon production in both the antiproton and antilambda channel. Results on dN/dy and inverse slope parameters are shown. A preliminary measurement of the ratio bar Λ/bar p is also presented

  4. Baryon - antibaryon asymmetry in central rapidity region at LHC ALICE

    International Nuclear Information System (INIS)

    Broz, M.

    2008-01-01

    Study of asymmetry in number of baryons and antibaryons in central rapidity region is important for clarification of baryon number carriers character. Effect we are interested in is small, can be hidden by systematical processes of particle track reconstruction and identification. To make corrections on these effects is the aim of this thesis. (author)

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Holme, A.K.

    1995-11-01

    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.

  7. 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)

    Holme, A.K.

    1995-11-01

    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

  8. A Critical Examination of the Models Proposed to Account for Baryon-Antibaryon Segregation Following the Quark-Hadron Transition

    Science.gov (United States)

    Garfinkle, Moishe

    2015-04-01

    The major concern of the Standard Cosmological Model (SCM) is to account for the continuing existence of the universe in spite of the Standard Particle Model (SPM). According to the SPM below the quark-hadron temperature (~ 150 +/- 50 MeV) the rate of baryon-antibaryon pair creation from γ radiation is in equilibrium with rate of pair annihilation. At freeze-out (~ 20 +/- 10 MeV) the rate of pair creation ceases. Henceforth only annihilation occurs below this temperature, resulting in a terminal pair ratio B+/ γ = B-/ γ ~ 10-18, insufficient to account for the present universe which would require a pair ratio minimum of at least B+/ γ = B-/ γ ~ 10-10. The present universe could not exist according to the SPM unless a mechanism was devised to segregation baryons from antibaryon before freeze-out. The SPM can be tweaked to accommodate the first two conditions but all of the mechanisms proposed over the past sixty years for the third condition failed. All baryon-number excursions devised were found to be reversible. The major concern of the SCM is to account for the continuing existence of the universe in spite of the SPM. The present universe could not exist according to the SPM unless a mechanism was devised to segregation baryons from antibaryon before freeze-out. It is the examination of these possible mechanisms that is subject of this work.

  9. 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¯.

  10. Applications of the superflavor symmetry to heavy baryon-antibaryon pair production in electron-positron collision

    International Nuclear Information System (INIS)

    Guo Xinheng; Jin Hongying; Li Xueqian.

    1994-12-01

    The baryons containing two heavy quarks and a light quark are believed to have the diquark-quark structure and the diquark composed of the two heavy quarks behaves as a point-like color-triplet scalar or vector. The superflavor symmetry can associate productions of such heavy baryon-antibaryon pair with the heavy meson production. The whole scenario is discussed in some details in the work, and the observation prospect in the future experiments is stressed. (author). 21 refs, 1 fig

  11. Baryon-antibaryon systems

    International Nuclear Information System (INIS)

    Kahana, S.H.

    A few simple situations involving the anti-B--B and B-nucleus systems are discussed in the nonrelativistic dynamical treatment that is hopefully justified by the particular nature of the elementary two-body states considered. Of particular relevance is the spectroscopy of nucleons, isobars and mesons as three-quark or two-quark composites. Anti-B-B molecular states, bound and resonant anti-B--B states, and many-body systems are considered. 22 references

  12. Investigation of the source size and strong interaction with the femtoscopic correlations of baryons and antibaryons in heavy-ion collisions registered by ALICE

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00508100

    The strong interaction is one of the four fundamental forces of nature. It binds together quarks inside protons and neutrons (which are example of baryons - particles composed of three quarks) and assures the stability of the atomic nucleus. Parameters describing the strong potential are also crucial for the neutron stars models used in astrophysics. What is more, a precise study of strongly interacting particles may help to better understand the process of baryon annihilation. The current knowledge of the strong interactions between baryons other than nucle- ons is limited - there exist only a few measurements of the cross sections for pairs of (anti)baryons. The reason is that in many cases it is not possible to perform scattering experiments with beams of particles and antiparticles, as the exotic matter (such as Λ, Ξ or Σ baryons) is very shot-living. This issue can be solved thanks to the recent particle colliders like the Large Hadron Collider and experiments dedicated to study the heavy-ion collisio...

  13. 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, ...

  14. Production of strange baryons and antibaryons in relativistic ion collisions

    CERN Multimedia

    2002-01-01

    A new state of matter - the quark-gluon plasma - may be produced in $^{32}$S interactions with heavy nuclei A (Ag, Cu, Pb and S targets) at beam momenta up to 200 GeV/c per nucleon. A possible signature of this state is a strongly enhanced yield of strange quark pairs. The aim of the experiment is therefore a measurement of differential cross sections for production of neutral kaons, $\\Lambda, \\Xi, \\Omega$ and their antiparticles with high statistics. Furthermore charged particle trajectories will be reconstructed and the total energy flow and its fluctuations will be determined in the forward c.m.s. hemisphere. \\\\\\\\The experiment is performed with a modified EHS configuration; its characteristic features are:\\\\\\\\ - Tracking chambers.\\\\ - A Cerenkov counter.\\\\ - A TPC for 3-dimensional unambiguous space point tracking.\\\\ - A magnet to sweep most of the produced particles from the tracking devices.\\\\ - Hadronic and electromagnetic calorimeters covering hermetically the forward c.m.s. hemisphere.\\\\ - ...

  15. e+e--annihilation into baryon-antibaryon pairs

    International Nuclear Information System (INIS)

    Koerner, J.G.; Kuroda, M.

    1976-07-01

    Using GVDM-type form factors we calculate the e + -e - production cross sections for the reactions e + e - → 1 + /2 - anti(1 +- /2), 1 + /2 - anti(3 +- /2), 1 + /2 - anti(5 + /2) and 3 + /2 - anti(3 + /2) including all prominent baryon resonances at energies of present and planned e + -e - storage ring machines. We also evaluate the cross section of charmed baryon pair production. Near their respective thresholds charmed and uncharmed baryon pair production are predicted to constitute comparable fractions of the total hadronic cross section. The calculated cross sections indicate that the interference of direct and 1-photon decay of the PSI-particles into baryon pairs is small. (orig.) [de

  16. 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. \\\\ \\\\

  17. Antibaryon to Baryon Production Ratios in Pb-Pb and p-p collision at LHC energies of the DPMJET-III Monte Carlo

    CERN Document Server

    Bopp, Fritz W.; Ranft, J.; Roesler, S.

    2008-01-01

    A sizable component of stopped baryons is predicted for pp and P bP b collisions at LHC. Based on an analysis of RHIC data within framework of our multichain Monte Carlo DPMJET-III the LHC predictions are presented.

  18. 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

  19. Structure of superheavy elements with Meson field theory and beyond

    International Nuclear Information System (INIS)

    Walter Greiner

    2005-01-01

    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 with modern meson field theories are reviewed. Furtheron, different channels of nuclear decay are discussed including cluster radioactivity, cold fission and cold multifragmentation. A perspective for future research is given. We also study the possibility of producing a new kind of nuclear system that in addition to ordinary nucleons contains a few antibaryons. 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 4 He to 208 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 a factor of 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 owing to significant reduction of the reaction Q values, the in-medium annihilation rates should be strongly suppressed, leading to relatively long-lived antibaryon- nucleus systems. Multinucleon annihilation channels are analyzed too. We have also estimated formation probabilities of bound antibaryon-nucleus systems in antiproton- nucleus reactions and have found that their observation will be feasible at the future GSI antiproton facility. Several observable signatures are proposed. The possibility of producing cold multi-quark-antiquark clusters is discussed. This opens the possibility for cold compression of nuclear matter - in contrast to the creation of hot and dense nuclear matter in nuclear shock waves created in

  20. Cascade production in p+p, p+A and A+A interactions at 158 A.GeV

    CERN Document Server

    Susa, T

    2002-01-01

    The NA49 experiment has measured the strange and multistrange baryons in minimum bias p+p, centrality selected p+Pb and central Pb+Pb collisions. We observe that the yields increase faster than the number of wounded nucleons when comparing p+Pb to p+p. As already observed in A+A collisions, the increase is larger for multistrange than for strange baryons and for baryons than for antibaryons. The antibaryon to baryon ratio at mid-rapidity shows a smooth decrease from p+p to Pb+Pb collisions. (5 refs).

  1. Hydrodynamic modelling for relativistic heavy-ion collisions at RHIC ...

    Indian Academy of Sciences (India)

    antibaryon (B− ¯B) annihilations in the hadronic evolution play important roles for the baryon yields, reducing the ..... namic (MUSIC) simulations have nicely described the integrated and differential vn data with (η/s)RHIC = 0.12 for 200 ... MUSIC with (η/s)LHC = 0.2 for the selected centrality bins [6,32]. Although these calcu-.

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

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

    Roč. 33, s01 (2004), s618-s620 ISSN 1434-6044 R&D Projects: GA AV ČR KSK1048102 Keywords : NA57 experiment * strange baryons and antibaryons * heavy ion collisions * centrality range * transverse mass spectra * Pb collisions Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 3.486, year: 2004

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

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

    Roč. 595, - (2004), s. 68-74 ISSN 0370-2693 R&D Projects: GA AV ČR KSK1048102 Keywords : strange baryon * antibaryon production * Pb-Pb collisions * NA57 experiment * CERN SPS * hyperon yields * mid-rapidity * silicon telescope * pixel detector Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.619, year: 2004

  4. B decays to baryons

    Indian Academy of Sciences (India)

    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.

  5. Strange baryon production in Z hadronic decays

    CERN Document Server

    Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Anykeyev, V B; Apel, W D; Arnoud, Y; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barate, R; Bardin, Dimitri Yuri; Barker, G J; Baroncelli, A; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bocci, V; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brunet, J M; Brückman, P; Bugge, L; Buran, T; Buys, A; Bärring, O; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Cassio, V; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chikilev, O G; Chliapnikov, P V; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; D'Almagne, B; Da Silva, W; Dahl-Jensen, Erik; Dahm, J; Dam, M; Damgaard, G; Daum, A; Dauncey, P D; Davenport, Martyn; De Angelis, A; De Boeck, H; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Defoix, C; Della Ricca, G; Delpierre, P A; Demaria, N; Di Ciaccio, Lucia; Dijkstra, H; Djama, F; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Dönszelmann, M; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Föth, H; Fürstenau, H; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gillespie, D; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Gracco, Valerio; Grard, F; Graziani, E; Grosdidier, G; Gunnarsson, P; Guy, J; Guz, Yu; Górski, M; Günther, M; Haedinger, U; Hahn, F; Hahn, M; Hahn, S; Haider, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Ioannou, P; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Joram, Christian; Juillot, P; Jönsson, L B; Jönsson, P E; Kaiser, M; Kalmus, George Ernest; Kapusta, F; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Królikowski, J; Kubinec, P; Kucewicz, W; Kurvinen, K L; Kuznetsov, O; Köhne, J H; Köne, B; La Vaissière, C de; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lokajícek, M; Loken, J G; Loukas, D; Lutz, P; Lyons, L; López, J M; López-Aguera, M A; López-Fernandez, A; Lörstad, B; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martí i García, S; Martínez-Rivero, C; Martínez-Vidal, F; Maréchal, B; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Meroni, C; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Monge, M R; Morettini, P; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Mönig, K; Møller, R; Müller, H; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Némécek, S; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Pape, L; Parodi, F; Passeri, A; Pegoraro, M; Pennanen, J; Peralta, L; Pernegger, H; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rídky, J; Rückstuhl, W; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schyns, M A E; Sciolla, G; Scuri, F; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stepaniak, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Stäck, H; Szczekowski, M; Szeptycka, M; Sánchez, J; Tabarelli de Fatis, T; Tavernet, J P; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tuuva, T; Tyapkin, I A; Tyndel, M; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van Doninck, W K; Van Eldik, J; Van der Velde, C; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Voutilainen, M; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Wehr, A; Weierstall, M; Weilhammer, Peter; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wormser, G; Woschnagg, K; Yip, K; Yu, L; Yushchenko, O P; Zach, F; Zacharatou-Jarlskog, C; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zhigunov, V P; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; de Boer, Wim; van Apeldoorn, G W; van Dam, P; Åsman, B; Österberg, K; Überschär, B; Überschär, S

    1995-01-01

    A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the \\Sigma^\\pm average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models.

  6. Fulltext PDF

    Indian Academy of Sciences (India)

    what we observe in the Universe today. Direct observation shows that the Universe around us contains no appreciable primordial antimatter. In addition, the stunning success of big bang nucleosynthesis rests on the requirement that, defining n () to be the number density of (anti)-baryons and s to be the entropy density,.

  7. Evidence for Leading Particle Production in e^+e^- arrowHadrons

    Science.gov (United States)

    Baird, Kenneth G.

    1996-05-01

    We present evidence for leading baryon production in hadronic decays of the Z^0 to light quark pairs using 150,000 events obtained in the SLD detector. The highly polarized electron beam produced by the SLC is used to tag q(barq)-jet hemispheres, and a signed impact parameter technique is used to reject heavy-flavor events. p(barp)'s are identified using the SLD Cherenkov Ring Imaging Detector, and Λ(barΛ)'s are detected by reconstructing the p(barp)π decay mode. We observe more high momentum baryons than antibaryons in the quark jets, and the opposite in antiquark jets. As an antibaryon is composed of valence antiquarks, this is direct evidence that high momentum (anti)particles in jets tend to contain the initial (anti)quark.

  8. Melting Hadrons, Boiling Quarks

    CERN Document Server

    Rafelski, Johann

    2015-09-22

    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.

  9. Baryon destruction by asymmetric dark matter

    International Nuclear Information System (INIS)

    Davoudiasl, Hooman; Morrissey, David E.; Tulin, Sean; Sigurdson, Kris

    2011-01-01

    We investigate new and unusual signals that arise in theories where dark matter is asymmetric and carries a net antibaryon number, as may occur when the dark matter abundance is linked to the baryon abundance. Antibaryonic dark matter can cause induced nucleon decay by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 10 29 -10 32 yrs in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic dark matter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter-induced baryon number violation. Finally, we discuss the effects of baryon-destroying dark matter on stellar systems and show that it can be consistent with existing observations.

  10. Cosmological baryon number domain structure from symmetry-breaking in grand unified field theories

    Science.gov (United States)

    Brown, R. W.; Stecker, F. W.

    1979-01-01

    It is suggested that grand unified field theories with spontaneous symmetry breaking in the very early big-bang can lead more naturally to a baryon symmetric cosmology with a domain structure than to a totally baryon asymmetric cosmology. The symmetry is broken in a randomized manner in causally independent domains, favoring neither a baryon nor an antibaryon excess on a universal scale. Arguments in favor of this cosmology and observational tests are discussed.

  11. Cosmological baryon-number domain structure from symmetry breaking in grand unified field theories

    Science.gov (United States)

    Brown, R. W.; Stecker, F. W.

    1979-01-01

    It is suggested that grand unified field theories with spontaneous symmetry breaking in the very early big bang can lead more naturally to a baryon-symmetric cosmology with a domain structure than to a totally baryon-asymmetric cosmology. The symmetry is broken in a randomized manner in causally independent domains, favoring neither a baryon nor an antibaryon excess on a universal scale. Arguments in favor of this cosmology and observational tests are discussed.

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

    International Nuclear Information System (INIS)

    Gaidos, J.A.; Koltick, D.S.; Loeffler, F.J.

    1983-01-01

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

    Energy Technology Data Exchange (ETDEWEB)

    Antinori, F.; Bacon, P.A.; Badala, 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.; Haas, A.P. de; Rijke, P.C. de; Di Bari, D.; Di Liberto, S.; Divia, R.; Elia, D.; 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.; Kolozhvari, A.A.; Kondratiev, V.; Kralik, I.; Kravcakova, A.; Kuijer, P.; Lenti, V.; Lietava, R.; Loevhoeiden, G.; Manzari, V.; Martinska, G.; Mazzoni, M.A.; Meddi, F.; Michalon, A.; Morando, M.; Nappi, E.; Navach, F.; Norman, P.I.; Palmeri, A.; Pappalardo, G.S.; Pastircak, B.; Pisut, J.; Posa, F.; Quercigh, E.; Riggi, F.; Roehrich, D.; Romano, G.; Safarik, K.; Sandor, L.; Schillings, E.; Segato, G.; Sene, M.; Sene, R.; Snoeys, W.; Soramel, F.; Spyropoulou-Stassinaki, M.; Staroba, P.; Toulina, T.A.; Turrisi, R.; Tveter, T.S.; Urban, J.; Valiev, F.; Brink, A. van den; Ven, P. van de; Vande Vyvre, P.; Eijndhoven, N. van; Hunen, J. van; Vascotto, A.; Vik, T.; Villalobos-Baillie, O.; Vinogradov, L.; Virgili, T.; Votruba, M.F.; Vrlakova, J.; Zavada, P

    2004-04-05

    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 mid-rapidity is discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Back, B. B.; Betts, R. R.; Chang, J.; Chang, W. C.; E917 Collaboration; Gillitzer, A.; Henning, W. F.; Hofman, D. J.; Nanal, V.; Wuosmaa, A. H.

    1999-08-04

    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.

  15. Cloudy bag model calculation of P11 πN scattering

    International Nuclear Information System (INIS)

    Rinat, A.S.

    1981-05-01

    πN, πΔ scattering in the cloudy bag model (CBM) is considered using an elementary π field and bare bag states for N, Δ, Nsup(*)(1470). The resulting 2-channel problem is solved neglecting intermediate states with anti-baryons and states with more than a single pion. It is shown that delta 11 may be reproduced for parameters close to their theoretical values. The fit thus provides a test for the CBM. (author)

  16. Local and nonlocal defect-mediated electroweak baryogenesis

    International Nuclear Information System (INIS)

    Brandenberger, R.; Davis, A.; Prokopec, T.; Trodden, M.

    1996-01-01

    We consider the effects of particle transport in topological defect-mediated electroweak baryogenesis scenarios. We analyze the cases of both thin and thick defects and demonstrate an enhancement of the original mechanism in both cases due to an increased effective volume in which baryogenesis occurs. This phenomenon is a result of an imperfect cancellation between the baryons and antibaryons produced on opposite faces of the defect. copyright 1996 The American Physical Society

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

    Energy Technology Data Exchange (ETDEWEB)

    Antinori, F.; Dainese, A. [University of Padua and INFN, Padua (Italy); Bacon, P.A.; Bhasin, A.; Bloodworth, I.J.; Bull, S.A.; Clarke, R.F. [School of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom); Badala, A.; Barbera, R. [University of Catania and INFN, Catania (Italy); Belogianni, A. [Physics Department, University of Athens, Athens (Greece); Bombara, M. [Institute of Experimental Physics, Slovak Academy of Science, Kosice (Slovakia); Bruno, G.E.; Caliandro, R.; Bari, D.Di [Dipartimento IA di Fisica dell' Universita e del Politecnico and INFN, Bari (Italy); Campbell, M.; Carena, W.; Carrer, N. [CERN, European Laboratory for Particle Physics, Geneva (Switzerland); Haas, A.P. de; Rijke, P.C. de [Utrecht University and NIKHEF, Utrecht (Netherlands); Liberto, S. Di [University ' ' La Sapienza' ' and INFN, Rome (Italy); Divia, R.; Elia, D.; 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.; Kolozhvari, A.A.; Kondratiev, V.; Kralik, I.; Kravcakova, A.; Kuijer, P.; Lenti, V.; Lietava, R.; Loevhoeiden, G.; Manzari, V.; Martinska, G.; Mazzoni, M.A.; Meddi, F.; Michalon, A.; Morando, M.; Nappi, E.; Navach, F.; Norman, P.I.; Palmeri, A.; Pappalardo, G.S.; Pastircak, B.; Pisut, J.; Pisutova, N.; Posa, F.; Quercigh, E.; Riggi, F.; Roehrich, D.; Romano, G.; Safarik, K.; Sandor, L.; Schillings, E.; Segato, G.; Sene, M.; Sene, R.; Snoeys, W.; Soramel, F.; Spyropoulou-Stassinaki, M.; Staroba, P.; Toulina, T.A.; Turrisi, R.; Tveter, T.S.; Urban, J.; Valiev, F.; Brink, A. van den; Ven, P. van de; Vyvre, P. Vande; Eijndhoven, N. van; Hunen, J. van; Vascotto, A.; Vik, T.; Baillie, O.Villalobos; Vinogradov, L.; Virgili, T.; Votruba, M.F.; Vrlakova, J.; Zav

    2004-07-01

    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.)

  18. Study of panti p and Λanti Λ production in π+-p reactions at 18.5 GeV/c

    International Nuclear Information System (INIS)

    Lichtman, S.; Bishop, J.M.; Biswas, N.N.; Cason, N.M.; Harrington, E.A. Jr.; Kenney, V.P.; Shephard, W.D.; Stuntebeck, P.H.

    1976-01-01

    Studies have been made of the rare reactions π + p→π + ppanti p and Λ+anti Λ+ anything, and of π - p→π - ppanti p and Λ+anti Λ+ anything, with cross sections of 18.5+-5.5, 10.7+-3.0, 12.0+-5.0, and 19.7+-4.8μb, respectively. Production characteristics of these reactions are examined and effective-mass spectra are presented. There is no significant evidence in the data for production of PSI (3095) in the baryon-antibaryon system, or for any other high-mass resonances. (Auth.)

  19. The impact of particle production on gravitational baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.A.S., E-mail: jas.lima@iag.usp.br [Departamento de Astronomia, Universidade de São Paulo, Rua do Matão 1226, 05508-900, São Paulo (Brazil); Singleton, D., E-mail: dougs@csufresno.edu [Department of Physics, California State University Fresno, Fresno, CA 93740-8031 (United States); ICTP South American Institute for Fundamental Research, UNESP – Univ. Estadual Paulista, Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Institute of Experimental and Theoretical Physics Al-Farabi KazNU, Almaty, 050040 (Kazakhstan)

    2016-11-10

    Baryogenesis driven by curvature effects is investigated by taking into account gravitationally induced particle production in the very early Universe. In our scenario, the baryon asymmetry is generated dynamically during an inflationary epoch powered by ultra-relativistic particles. The adiabatic particle production rate provides both the needed negative pressure to accelerate the radiation dominated Universe and a non-zero chemical potential which distinguishes baryons and anti-baryons thereby producing a baryon asymmetry in agreement with the observed value. Reciprocally, the present day asymmetry may be used to determine the inflationary scale at early times. Successful gravitational baryogenesis is dynamically generated for many different choices of the relevant model parameters.

  20. 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.

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

    International Nuclear Information System (INIS)

    Gaidos, J.A.; Koltick, D.S.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Willmann, R.B.

    1982-01-01

    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

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

    International Nuclear Information System (INIS)

    Sorge, H.

    1995-09-01

    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.)

  3. Baryogenesis from oscillations of charmed or beautiful baryons

    Science.gov (United States)

    Aitken, Kyle; McKeen, David; Neder, Thomas; Nelson, Ann E.

    2017-10-01

    We propose a model for C P -violating oscillations of neutral, heavy-flavor baryons into antibaryons at rates which are within a few orders of magnitude of their lifetimes. The flavor structure of the baryon violation suppresses neutron oscillations and baryon-number-violating nuclear decays to experimentally allowed rates. We also propose a scenario for producing such baryons in the early Universe via the out-of-equilibrium decays of a neutral particle, after hadronization but before nucleosynthesis. We find parameters where C P -violating baryon oscillations at a temperature of a few MeV could result in the observed asymmetry between baryons and antibaryons. Furthermore, part of the relevant parameter space for baryogenesis is potentially testable at Belle II via decays of heavy-flavor baryons into an exotic neutral fermion. The model introduces four new particles: three light Majorana fermions and a colored scalar. The lightest of these fermions is typically long lived on collider time scales and may be produced in decays of bottom and possibly charmed hadrons.

  4. 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.

  5. Inclusive spectra of hadron resonances in the framework of multiparton recombination model: 2. Pion and kaon fragmentation

    International Nuclear Information System (INIS)

    Badalyan, N.N.; Badalyan, R.G.; Gulkanyan, G.R.

    1986-01-01

    Inclusive spectra of ''direct'' fragmentation of pion and kaon into meson and baryon resonances are obtained in the framework of multiparton recombination model. The parameters of distribution of sea partons in pion and kaon are estimated from the comparison of model predictions with the experimental data. Satisfactorily are described the inclusive spectra of meson ρ 0 , φ, K ±,0 (890), K ±,0 (1430) and antibaryon Σ-bar ± (1385) resonances in a wide range over the Feynman variable x, and also baryon resonances Σ ± (1385), Δ ++ (1232) at x>0.4 in the fragmentation region of pion and kaon in πP- and KP-interactions at high energies

  6. 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.

  7. 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.)

  8. On the Feasibility of a Stop NLSP in Gravitino Dark Matter Scenarios

    CERN Document Server

    Díaz-Cruz, J L; Olive, K A; Santoso, Y; Ellis, John; Olive, Keith A.; Santoso, Yudi

    2007-01-01

    We analyze the possibility that the lighter stop {\\tilde t_1} could be the next-to-lightest supersymmetric particle (NLSP) in models where the gravitino is the lightest supersymmetric particle (LSP). We do not find any possibility for a stop NLSP in the constrained MSSM with universal input soft supersymmetry-breaking masses at the GUT scale (CMSSM), but do find small allowed regions in models with non-universal Higgs masses (NUHM). We discuss the cosmological evolution of stop hadrons. Most {\\tilde t_1}qq `sbaryons' and the corresponding `antisbaryons' annihilate with conventional antibaryons and baryons into {\\tilde t_1}{\\bar q} `mesinos' and the corresponding `antimesinos', respectively, shortly after the quark-hadron transition in the early Universe, and most mesinos and antimesinos subsequently annihilate. As a result, insufficient metastable charged stop hadrons survive to alter Big Bang nucleosynthesis.

  9. Production of multi-strange baryons in 7 TeV proton-proton collisions with ALICE

    CERN Document Server

    Maire, Antonin

    2012-01-01

    In the perspective of comparisons between proton-proton and heavy-ion physics, understanding the production mechanisms (soft and hard) in pp that lead to strange particles is of importance. Measurements of charged multi-strange (anti-)baryons (Omega and Xi) are presented for pp collisions at sqrt(s) = 7 TeV. This report is based on results obtained by ALICE (A Large Ion Collider Experiment) from the 2010 data-taking. Taking advantage of the characteristic cascade-decay topology, the identification of Xi-, anti-Xi+, Omega- and anti-Omega+ can be performed, over a wide range of momenta (e.g. from 0.6 to 8.5 GeV/c for Xi-, with the present statistics analysed). The production at central rapidity (|y| < 0.5) as a function of transverse momentum, dN/dptdy, is presented. These results are compared to PYTHIA Perugia 2011 predictions.

  10. Novel mechanisms of baryon number flow over large rapidity gap

    International Nuclear Information System (INIS)

    Kopeliovich, B.Z.; Zakharov, B.G.

    1988-01-01

    It is shown that slow valence quark in the wave function of high energy proton can fragment into a baryon if the fast diquark-spectator is disintegrated, i.e. is turned from the antitriplet to the sextet colour state. The cross section of the baryon number flow to the central rapidly region using the perturbutive QCD are estimated. It depends on the rapidly gap δ y as exp(-δ y/2 ) and nicely agrees with the data at ISR energies. There exists also an intriguing possibillity of tranfering baryon number by means of gluonic exchanges only. This contribution does not depend on rapidity at all and becomes sizable in TeV energy region. New mechanisms for baryon-antibaryon production from vacuum, transfer of polarization over large rapidity intervals, and nuclear stopping power are propsed

  11. 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...

  12. Some aspects of matter-antimatter asymmetry and states in the Universe

    International Nuclear Information System (INIS)

    Braghin, Fabio L.

    2011-01-01

    Full text: Matter-antimatter asymmetry observed in our Universe is discussed considering different aspects. The usual baryogenesis mechanism proposed by Sakharov is described and and few other mechanisms are analyzed. Furthermore, the possibility of the existence of antimatter islands is discussed in view of different observational results and plans for future observations. For the different mechanisms of producing such asymmetry, besides the breaking of CP, particular attention is given to CPT , considering both its possible breakdown in different systems and the framework of the CPT theorem, and to few other different effects which are (or might be) present in the (extended) phase diagram of strong interacting systems and which might not rely on non-equilibrium conditions. Some ideas of relevance for finite (anti)baryonic density systems are discussed as well. (author)

  13. The HIBEAM Experiment at the ESS

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The European Spallation Source (ESS) offers an opportunity for a fundamental physics program with a unique reach which is complementary to that at other facilities. In this talk, the HIBEAM project is described. The HIBEAM collaboration has proposed a suite of searches and measurements which would use the Large ESS Beam Port with a high cold neutron flux. The program includes searches for conversions of free neutrons to antineutrons and to mirror neutrons with regeneration, as well as precision measurements of parity violation in nucleon-nucleon interactions. The high cold neutron intensity at HIBEAM would provide a higher sensitivity for the searches and measurements than was achieved at earlier experiments. The physics program addresses some of the central unresolved questions in particle physics and cosmology such as the energy scale and mechanism for baryon number violation, the origin of the baryon-antibaryon asymmetry of the universe, the composition of dark matter, and the mechanism for neutrino mass...

  14. 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.

  15. 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)

    Tortorella, D.

    2007-01-01

    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 A ), the neutron lifetime (τ 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.)

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

    Directory of Open Access Journals (Sweden)

    Ya-Hui Chen

    2015-01-01

    Full Text Available The transverse momentum and rapidity distributions of net-baryons (baryons minus antibaryons 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 analyses of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

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

    International Nuclear Information System (INIS)

    Abelev, B. I.; Baumgart, S.; Bielcik, J.; Bielcikova, J.; Caines, H.; Catu, O.; Chikanian, A.; Du, F.; Finch, E.; Harris, J. W.; Heinz, M.; Knospe, A. G.; Lamont, M. A. C.; Lin, G.; Majka, R.; Nattrass, C.; Salur, S.; Sandweiss, J.; Smirnov, N.; Witt, R.

    2007-01-01

    We present STAR measurements of the azimuthal anisotropy parameter v 2 for pions, kaons, protons, Λ,Λ,Ξ+Ξ, and Ω+Ω, along with v 4 for pions, kaons, protons, and Λ+Λ at midrapidity for Au+Au collisions at √(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 √(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 nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon v 2 is larger than antibaryon v 2 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 v 2 or that antibaryon and baryon annihilation is larger in the in-plane direction

  18. Challenging the Standard Model: High-Precision Comparisons of the Fundamental Properties of Protons and Antiprotons

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    The Baryon Antibaryon Symmetry Experiment (BASE-CERN) at CERN’s antiproton decelerator facility is aiming at high-precision comparisons of the fundamental properties of protons and antiprotons, such as charge-to-mass ratios, magnetic moments and lifetimes. Such experiments provide sensitive tests of the fundamental charge-parity-time invariance in the baryon sector. BASE was approved in 2013 and has measured since then, utilizing single-particle multi-Penning-trap techniques, the antiproton-to-proton charge-to-mass ratio with a fractional precision of 69 p.p.t. [1], as well as the antiproton magnetic moment with fractional precisions of 0.8 p.p.m. and 1.5 p.p.b., respectively [2]. At our matter companion experiment BASE-Mainz, we have performed proton magnetic moment measurements with fractional uncertainties of 3.3 p.p.b. [3] and 0.3 p.p.b. [4]. By combining the data of both experiments we provide a baryon-magnetic-moment based CPT test gpbar/gp = 1.000 000 000 2(15), which improves the uncertainty of p...

  19. 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)

  20. 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...

  1. Beam energy dependence of d and d ‾ production in Au+Au collisions at RHIC

    Science.gov (United States)

    Yu, Ning; STAR Collaboration

    2017-11-01

    The binding energy of light nuclei is small compared to the temperature of the system created in heavy-ion collisions. Consequently, the yields of light nuclei can be used to probe the freeze-out properties, such as correlation volume and local baryon density of the medium created in high-energy nuclear collisions. In this paper, we report the results of deuteron and anti-deuteron production in Au+Au collision at √{sNN} = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, measured by STAR at RHIC. The collision energy, centrality and transverse momentum dependence of the coalescence parameter B2 for deuteron and anti-deuteron production are discussed. We find the values of B2 for anti-deuterons are systematically lower than those for deuterons indicating the correlation volume of anti-baryon are larger than that of baryon. In addition, the values of B2 are found to vary with collision energy and show a broad minimum around √{sNN} = 20GeV, implying a change of the equation of state of the medium in these collisions.

  2. 13th Workshop on What Comes Beyond the Standard Models

    CERN Document Server

    Nielsen, Holger Bech; Lukman, Dragan; What Comes Beyond the Standard Models

    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...

  3. 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 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Abelev, B.I.; Adams, J.; 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.; Bystersky, M.; Cadman, R.V.; Cai,X.Z.; Caines, H.; Calderon 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.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, 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 Mazumdar, 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, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti,M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos,H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo,Y.; Gupta,N.; Gutierrez, 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.; et al.

    2006-07-31

    We present strange particle spectra and yields measured atmid-rapidity in sqrt text s=200 GeV proton-proton (p+p) collisions atRHIC. We find that the previously observed universal transverse mass(mathrm mT \\equiv\\sqrt mathrm p_T 2+\\mathrm m2) scaling of hadronproduction in p+p collisions seems to break down at higher \\mt and thatthere is a difference in the shape of the \\mt spectrum between baryonsand mesons. We observe mid-rapidity anti-baryon to baryon ratios nearunity for Lambda and Xi baryons and no dependence of the ratio ontransverse momentum, indicating that our data do not yet reach thequark-jet dominated region. We show the dependence of the mean transversemomentum (\\mpt) on measured charged particle multiplicity and on particlemass and infer that these trends are consistent with gluon-jet dominatedparticle production. The data are compared to previous measurements fromCERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next toLeading order (NLO) string fragmentation model predictions. We infer fromthese comparisons that the spectral shapes and particle yields from $p+p$collisions at RHIC energies have large contributions from gluon jetsrather than quark jets.

  5. 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, John; 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.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sancez, M.; Castillo, J.; Catu, O.; Cebra, D.A.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Chen, Y.; Cheng, J.; Cherney, Michael G.; 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.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, 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 Mazumdar, 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, Y.; Fornazier, K.S.F.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Gans, J.; Ganti, M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Gorbunov, Y.G.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guo, Y.; Gupta, A.; Gupta, N.; Gutierrez, 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.; Kramer, M.; Kravtsov, P.; Kravtsov, V.I.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kuznetsov, A.A.; Lamont, M.A.C.; Landgraf, J.M.; Lange, S.; LaPointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.H.; Lehocka, S.; LeVine, Micheal J.; 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.; Lopez-Noriega, M.; Love, W.A.; Lu, Y.; Ludlam, T.; Lynn, D.; 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.; Matis, H.S.; Matulenko, Yu.A.; McClain, C.J.; McShane, T.S.; Melnick, Yu.; Meschanin, A.; Miller, M.L.; Milos, M.; Minaev, N.G.; Mioduszewski, S.; Mironov, C.; Mischke, A.; Mishra, D.K.; Mitchell, J.; Mohanty, B.; Molnar, L.; Moore, C.F.; Morozov, D.A.; Munhoz, M.G.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Nelson, J.M.; Netrakanti, P.K.; Nikitin, V.A.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pal, S.K.; Panebratsev, Y.; Panitkin, S.Y.; Pavlinov, A.I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Petrov, V.A.; Phatak, S.C.; Picha, R.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Porter, J.; Poskanzer, A.M.; Potekhin, M.; Potrebenikova, E.; 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.; Retiere, F.; Ridiger, A.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, 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, Igor A.; 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.; Shimanskiy, S.S.; Sichtermann, E; Simon, F.; Singaraju, R.N.; Smirnov, N.; Snellings, R.; Sood, G.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H.M.; Srivastava, B.; Stadnik, A.; Stanislaus, T.D.S.; Stock, R.; Stolpovsky, A.; Strikhanov, M.; Stringfellow, B.; Suaide, A.A.P.; Sugarbaker, E.; 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.; 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, David G.; Van Buren, G.; van der Kolk, N.; van Leeuwen, M.; Vander Molen, A.M.; Varma, R.; Vasilevski, I.M.; Vasiliev, 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., Jr.; 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.; Zborovsky, 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.; Braem, A.; Davenport, M.; De Cataldo, G.; Di Bari, D.; Di Mauro, A.; Kunde, G.J.; Martinengo, P.; Nappi, E.; Paic, G.; Posa, E.; Piuz, F.; Schyns, E.

    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.

  6. Evidence for an exotic S= -2, Q= -2 baryon resonance in proton-proton collisions at the CERN SPS.

    Science.gov (United States)

    Alt, C; Anticic, T; Baatar, B; Barna, D; Bartke, J; Betev, L; Białkowska, H; Billmeier, A; Blume, C; Boimska, B; Botje, M; Bracinik, J; Bramm, R; Brun, R; Buncić, P; Cerny, V; Christakoglou, P; Chvala, O; Cramer, J G; Csató, P; Darmenov, N; Dimitrov, A; Dinkelaker, P; Eckardt, V; Farantatos, G; Filip, P; Flierl, D; Fodor, Z; Foka, P; Freund, P; Friese, V; Gál, J; Gaździcki, M; Georgopoulos, G; Gładysz, E; Hegyi, S; Höhne, C; Kadija, K; Karev, A; Kniege, S; Kolesnikov, V I; Kollegger, T; Korus, R; Kowalski, M; Kraus, I; Kreps, M; van Leeuwen, M; Lévai, P; Litov, L; Makariev, M; Malakhov, A I; Markert, C; Mateev, M; Mayes, B W; Melkumov, G L; Meurer, C; Mischke, A; Mitrovski, M; Molnár, J; Mrówczyński, St; Pálla, G; Panagiotou, A D; Panayotov, D; Perl, K; Petridis, A; Pikna, M; Pinsky, L; Pühlhofer, F; Reid, J G; Renfordt, R; Retyk, W; Roland, C; Roland, G; Rybczyński, M; Rybicki, A; Sandoval, A; Sann, H; Schmitz, N; Seyboth, P; Siklér, F; Sitar, B; Skrzypczak, E; Stefanek, G; Stock, R; Ströbele, H; Susa, T; Szentpétery, I; Sziklai, J; Trainor, T A; Varga, D; Vassiliou, M; Veres, G I; Vesztergombi, G; Vranić, D; Wetzler, A; Włodarczyk, Z; Yoo, I K; Zaranek, J; Zimányi, J

    2004-01-30

    Results of resonance searches in the Xi(-)pi(-), Xi(-)pi(+), Xi;(+)pi(-), and Xi;(+)pi(+) invariant mass spectra in proton-proton collisions at sqrt[s]=17.2 GeV are presented. Evidence is shown for the existence of a narrow Xi(-)pi(-) baryon resonance with mass of 1.862+/-0.002 GeV/c(2) and width below the detector resolution of about 0.018 GeV/c(2). The significance is estimated to be above 4.2sigma. This state is a candidate for the hypothetical exotic Xi(--)(3/2) baryon with S=-2, I=3 / 2, and a quark content of (dsdsū). At the same mass, a peak is observed in the Xi(-)pi(+) spectrum which is a candidate for the Xi(0)(3/2) member of this isospin quartet with a quark content of (dsus[-]d). The corresponding antibaryon spectra also show enhancements at the same invariant mass.

  7. 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.)

  8. Measurement of baryon production in B-meson decay

    International Nuclear Information System (INIS)

    Crawford, G.; Fulton, R.; Jensen, T.; Johnson, D.R.; Kagan, H.; Kass, R.; Malchow, R.; Morrow, F.; Whitmore, J.; Wilson, P.; Bortoletto, D.; Brown, D.; Dominick, J.; McIlwain, R.L.; Miller, D.H.; Modesitt, M.; Ng, C.R.; Schaffner, S.F.; Shibata, E.I.; Shipsey, I.P.J.; Battle, M.; Kroha, H.; Sparks, K.; Thorndike, E.H.; Wang, C.; Alam, M.S.; Kim, I.J.; Li, W.C.; Lou, X.C.; Nemati, B.; Romero, V.; Sun, C.R.; Wang, P.; Zoeller, M.M.; Goldberg, M.; Haupt, T.; Horwitz, N.; Jain, V.; Kennett, R.; Mestayer, M.D.; Moneti, G.C.; Rozen, Y.; Rubin, P.; Skwarnicki, T.; Stone, S.; Thusalidas, M.; Yao, W.; Zhu, G.; Barnes, A.V.; Bartelt, J.; Csorna, S.E.; Letson, T.; Alexander, J.; Artuso, M.; Bebek, C.; Berkelman, K.; Besson, D.; Browder, T.; Cassel, D.G.; Cheu, E.; Coffman, D.M.; Drell, P.S.; Ehrlich, R.; Galik, R.S.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Honscheid, K.; Kandaswamy, J.; Katayama, N.; Kreinick, D.L.; Lewis, J.D.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Nandi, S.; Nordberg, E.; O'Grady, C.; Patterson, J.R.; Peterson, D.; Pisharody, M.; Riley, D.; Sapper, M.; Selen, M.; Silverman, A.; Worden, H.; Worris, M.; Sadoff, A.J.; Avery, P.; Freyberger, A.; Rodriguez, J.; Yelton, J.; Henderson, S.; Kinoshita, K.; Pipkin, F.; Procario, M.; Saulnier, M.; Wilson, R.; Wolinski, J.; Xiao, D.; Yamamoto, H.; Ammar, R.; Baringer, P.; Coppage, D.; Davis, R.; Haas, P.; Kelly, M.; Kwak, N.; Lam, H.; Ro, S.; Kubota, Y.; Nelson, J.K.; Perticone, D.; Poling, R.; Schrenk, S.

    1992-01-01

    Using the CLEO detector at the Cornell Electron Storage Ring, we observe B-meson decays to Λ c + and report on improved measurements of inclusive branching fractions and momentum spectra of other baryons. For the inclusive decay bar B→Λ c + X with Λ c + →pK - π + , we find that the product branching fraction B(bar B→Λ c + X)B(Λ c + →pK - π + )=(0.273±0.051± 0.039)%. Our measured inclusive branching fractions to noncharmed baryons are B(B→pX)=(8.0±0.5±0.3)%, B(B→ΛX)=(3.8±0.4±0.6)%, and B(B→Ξ - X)=(0.27±0.05±0.04)%. From these rates and studies of baryon-lepton and baryon-antibaryon correlations in B decays, we have estimated the branching fraction B(bar B→Λ c + X) to be (6.4±0.8±0.8)%. Combining these results, we calculate B(Λ c + →pK - π + ) to be (4.3±1.0±0.8)%

  9. Strange particle production in p+p, p+Pb and Pb+Pb interactions from NA49

    CERN Document Server

    Kadija, K

    2002-01-01

    Recent NA49 results on Lambda , Lambda , Xi /sup -/ and Xi /sup +/ production in minimum-bias p+p and centrality-selected p+Pb collisions at 158 GeV/c, and the results on Lambda , Lambda , K/sup + / and K/sup -/ production in central Pb+Pb collisions at 40, 80 and 158 A GeV are discussed and compared with other available data. By comparing the energy dependence of Lambda and Lambda production at mid-rapidity a striking similarity is observed between p+p and A+A data. This is also seen in the energy dependence of the Lambda / pi ratio. K/sup +// pi at mid-rapidity is affected in a similar way, due to the associated production of K/sup +/ together with Lambda particles. The observed yields increase faster than the number of wounded nucleons when comparing p+Pb to p+p. As already observed in A+A collisions, the increase is larger for multistrange than for strange baryons and for baryons than for anti-baryons. (11 refs).

  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. Research in Theoretical High Energy Nuclear Physics at the University of Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Rafelski, Johann [Univ. of Arizona, Tucson, AZ (United States). Dept. of Physics

    2016-03-28

    In the past decade (2004-2015) we addressed the quest for the understanding of how quark confinement works, how it can be dissolved in a limited space-time domain, and what this means: i) for the paradigm of the laws of physics of present day; and, ii) for our understanding of cosmology. The focus of our in laboratory matter formation work has been centered on the understanding of the less frequently produced hadronic particles (e.g. strange antibaryons, charmed and beauty hadrons, massive resonances, charmonium, Bc). We have developed a public analysis tool, SHARE (Statistical HAdronization with REsonances) which allows a precise model description of experimental particle yield and fluctuation data. We have developed a charm recombination model to allow for off-equilibrium rate of charmonium production. We have developed methods and techniques which allowed us to study the hadron resonance yield evolution by kinetic theory. We explored entropy, strangeness and charm as signature of QGP addressing the wide range of reaction energy for AGS, SPS, RHIC and LHC energy range. In analysis of experimental data, we obtained both statistical parameters as well as physical properties of the hadron source. The following pages present listings of our primary writing on these questions. The abstracts are included in lieu of more detailed discussion of our research accomplishments in each of the publications.

  12. Study ofe+e- to Lambda anti-Lambda, Lambda anti-Sigma^0,Sigma^0 anti-Sigma^0 using Initial State Radiation with BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.

    2007-09-14

    We study the e+e- --> Lambda anti-Lambda gamma, Lambda anti-Sigma0 gamma, Sigma0 anti-Sigma0 gamma processes using 230 fb-1 of integrated luminosity collected by the BaBar detector at e+e- center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 are measured in the dibaryon mass range from threshold up to 3 GeV/c{sup 2}. The ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for e+e- --> Lambda anti-Lambda, and limits on the relative phase between Lambda form factors are obtained. We also measure the J/psi --> Lambda anti-Lambda, Sigma0 anti-Sigma0 and psi(2S) --> Lambda anti-Lambda branching fractions.

  13. 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.

  14. 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; 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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; 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Zyzak, Maksym

    2015-08-17

    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...

  15. Hadron production in light and heavy, quark and antiquark jets

    International Nuclear Information System (INIS)

    Baird, K.G.

    1996-08-01

    The authors review four hadronization studies performed by the SLD experiment at SLAC, involving separation of light (Z 0 → u anti u, d anti d, s anti s), c, and b flavors using precision vertexing, and separation of q- and anti q-jets using the highly polarized SLC electron beam. They measured the differences between the average charged multiplicities in Z 0 → light, → c anti c, and →b anti b events, and found that the results were consistent with predictions of perturbative QCD. Next, they measured π/Κ/p/Κ 0 /Λ 0 production in light events for the first time, and compared with production in c- and b-flavor events. They then examined particle production differences in light quark and antiquark hemispheres, and observed more high momentum baryons and K - 's than antibaryons and K + 's in quark hemispheres, consistent with the leading particle hypothesis. Lastly, they performed a search for jet handedness in light q- and anti q-jets. Assuming Standard Model values of quark polarization in Z 0 decays, they have set an improved upper limit on the analyzing power of the handedness method

  16. Jet Hadronization via Recombination of Parton Showers in Vacuum and in Medium

    Energy Technology Data Exchange (ETDEWEB)

    Fries, Rainer J.; Han, Kyongchol; Ko, Che Ming

    2016-12-15

    We introduce a hadronization algorithm for jet parton showers based on a hybrid approach involving recombination of quarks and fragmentation of strings. The algorithm can be applied to parton showers from a shower Monte Carlo generator at the end of their perturbative evolution. The algorithm forces gluon decays and then evaluates the recombination probabilities for quark-antiquark pairs into mesons and (anti)quark triplets into (anti)baryons. We employ a Wigner phase space formulation based on the assumption of harmonic oscillator wave functions for stable hadrons and resonances. Partons too isolated in phase space to find recombination partners are connected by QCD strings to other quarks. Fragmentation of those remnant strings and the decay of all hadron resonances complete the hadronization process. We find that our model applied to parton showers from the PYTHIA Monte Carlo event generator leads to results very similar to pure Lund string fragmentation. We suggest that our algorithm can be readily generalized to jets embedded in quark-gluon plasma by adding sampled thermal partons from the phase transition hypersurface. The recombination of thermal partons and shower partons leads to an enhancement of pions and protons at intermediate momentum at both RHIC and LHC.

  17. CRN: 1987 Progress Report

    International Nuclear Information System (INIS)

    1988-01-01

    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 [fr

  18. Some cosmological consequences of primordial black-hole evaporations

    International Nuclear Information System (INIS)

    Carr, B.J.

    1976-01-01

    According to Hawking, primordial black holes of less than 10 15 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 10 15 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 10 15 g. Primordial black holes of less than 10 14 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 10 15 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

  19. 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.

  20. 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.

  1. The PANDA detector and its physics program at FAIR

    International Nuclear Information System (INIS)

    Brinkmann, K.

    2005-01-01

    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

  2. SOLAR CONSTRAINTS ON ASYMMETRIC DARK MATTER

    International Nuclear Information System (INIS)

    Lopes, Ilídio; Silk, Joseph

    2012-01-01

    The dark matter content of the universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the universe, the dark matter particles are produced in a process similar to baryogenesis, and dark matter freezeout depends on the dark matter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels) of particles and antiparticles. In these η-parameterized asymmetric dark matter (ηADM) models, the dark matter particles have an annihilation cross section close to the weak interaction cross section, and a value of dark matter asymmetry η close to the baryon asymmetry η B . Furthermore, we assume that dark matter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT, and CRESST experiments. Here, we constrain ηADM by investigating the impact of such a type of dark matter on the evolution of the Sun, namely, the flux of solar neutrinos and helioseismology. We find that dark matter particles with a mass smaller than 15 GeV, a spin-independent scattering cross section on baryons of the order of a picobarn, and an η-asymmetry with a value in the interval 10 –12 -10 –10 , would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct dark matter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological ηADM scenarios that we discuss have a relic dark matter density Ωh 2 and baryon asymmetry η B in agreement with the current WMAP measured values, Ω DM h 2 = 0

  3. SQUIDs as detectors in a new experiment to measure the neutron electric dipole moment

    International Nuclear Information System (INIS)

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

    1998-01-01

    A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10 -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 (∼100 cm 2 ) pick-up coils to measure the precision frequency of the spin-polarized 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 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 ∼2x10 -16 Tm 2 (0.1 Φ 0 ) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of dΦ SQ = 2x10 -6 Φ 0 /√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 the authors designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and they developed a two-SQUID readout system that will reduce SQUID noise in the experiment. They present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. The authors also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique