OPUS 4 | Search

Elliptic flow in Au+Au collisions at sqrt sNN = 130 GeV (2001)

Clemens Adler J. Berger Dominik Bernhard Flierl M. Gazdzicki S. Lange Rainer Ernst Arno Renfordt D. Roehrich Reinhard Stock Herbert Ströbele Christof Struck

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt[sNN] = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Measurement of charged jet suppression in Pb-Pb collisions at √sNN = 2.76 TeV (2014)

B. Abelev J. Adam D. Adamová M. M. Aggarwal G. Aglieri Rinella M. Agnello A.i G. Agocs A. Agostinelli N. Agrawal Z. Ahammed N. Ahmad A. Ahmad Masoodi I. Ahmed S. U. Ahn S. A. Ahn I. Aimo S. Aiola M. Ajaz A. Akindinov D. Aleksandrov B. Alessandro D. Alexandre A. Alici A. Alkin J. Alme T. Alt V. Altini S. Altinpinar I. Altsybeev C. Alves Garcia Prado C. Andrei A. Andronic V. Anguelov J. Anielski T. Antičić F. Antinori P. Antonioli L. Aphecetche Harald Appelshäuser N. Arbor S. Arcelli N. Armesto R. Arnaldi T. Aronsson I. C. Arsene M. Arslandok A. Augustinus R. Averbeck T. C. Awes M. D. Azmi M. Bach A. Badalà Y. W. Baek S. Bagnasco R. Bailhache V. Bairathi R. Bala A. Baldisseri F. Baltasar Dos Santos Pedrosa J. Bán R. C. Baral R. Barbera F. Barile G. G. Barnaföldi L. S. Barnby V. Barret J. Bartke M. Basile N. Bastid S. Basu B. Bathen G. Batigne B. Batyunya P. C. Batzing C. Baumann I. G. Bearden H. Beck C. Bedda N. K. Behera I. Belikov F. Bellini R. Bellwied E. Belmont-Moreno G. Bencedi S. Beole I. Berceanu G. G. Barnaföldi L. S. Barnby V. Barret J. Bartke M. Basile N. Bastid S. Basu B. Bathen G. Batigne B. Batyunya P. C. Batzing C. Baumann I. G. Bearden H. Beck C. Bedda N. K. Behera I. Belikov F. Bellini R. Bellwied E. Belmont-Moreno G. Bencedi S. Beole I. Berceanu M. Bogolyubsky L. Boldizsár M. Bombara J. Book H. Borel A. Borissov J. Bornschein F. Bossú M. Botje E. Botta S. Böttger P. Braun-Munzinger M. Bregant T. Breitner T. A. Broker T. A. Browning M. Broz E. Bruna G. E. Bruno D. Budnikov H. Buesching S. Bufalino P. Buncic O. Busch Z. Buthelezi D. Caffarri X. Cai H. Caines A. Caliva E. Calvo Villar P. Camerini V. Canoa Roman F. Carena W. Carena F. Carminati A. Casanova Díaz J. Castillo Castellanos E. A. R. Casula V. Catanescu C. Cavicchioli C. Ceballos Sanchez J. Cepila P. Cerello B. Chang S. Chapeland J. L. Charvet S. Chattopadhyay S. Chattopadhyay M. Cherney C. Cheshkov B. Cheynis V. Chibante Barroso D. D. Chinellato P. Chochula M. Chojnacki S. Choudhury P. Christakoglou C. H. Christensen P. Christiansen T. Chujo S. U. Chung C. Cicalo L. Cifarelli F. Cindolo J. Cleymans F. Colamaria D. Colella A. Collu M. Colocci G. Conesa Balbastre Z. Conesa del Valle M. E. Connors G. Contin J. G. Contreras T. M. Cormier Y. Corrales Morales P. Cortese I. Cortés Maldonado M. R. Cosentino F. Costa P. Crochet R. Cruz Albino E. Cuautle L. Cunqueiro A. Dainese R. Dang A. Danu D. Das I. Das K. Das S. Das A. Dash S. Dash S. De H. Delagrange A. Deloff E. Dénes G. D’Erasmo G. O. V. de Barros A. De Caro G. de Cataldo J. de Cuveland A. De Falco D. De Gruttola N. De Marco S. De Pasquale R. de Rooij M. A. Diaz Corchero T. Dietel R. Divià D. Di Bari S. Di Liberto A. Di Mauro P. Di Nezza Ø. Djuvsland A. Dobrin T. Dobrowolski D. Domenicis Gimenez B. Dönigus O. Dordic S. Dorheim A. K. Dubey A. Dubla L. Ducroux P. Dupieux A. K. Dutta Majumdar D. Elia H. Engel B. Erazmus H. A. Erdal D. Eschweiler B. Espagnon M. Estienne S. Esumi D. Evans S. Evdokimov G. Eyyubova D. Fabris J. Faivre D. Falchieri A. Fantoni M. Fasel D. Fehlker L. Feldkamp D. Felea A. Feliciello G. Feofilov J. Ferencei A. Fernández Téllez E. G. Ferreiro A. Ferretti A. Festanti J. Figiel M. A. S. Figueredo S. Filchagin D. Finogeev F. M. Fionda E. M. Fiore E. Floratos M. Floris S. Foertsch P. Foka S. Fokin E. Fragiacomo A. Francescon U. Frankenfeld U. Fuchs C. Furget M. Fusco Girard J. J. Gaardhøje M. Gagliardi M. Gallio D. R. Gangadharan P. Ganoti C. Garabatos E. Garcia-Solis C. Gargiulo I. Garishvili J. Gerhard M. Germain A. Gheata M. Gheata B. Ghidini P. Ghosh S.K. Ghosh P. Gianotti P. Giubellino E. Gladysz-Dziadus P. Glässel R. Gomez P. González-Zamora S. Gorbunov L. Görlich S. Gotovac L. K. Graczykowski R. Grajcarek A. Grelli A. Grigoras C. Grigoras V. Grigoriev A. Grigoryan S. Grigoryan B. Grinyov N. Grion J. F. Grosse-Oetringhaus J.-Y. Grossiord R. Grosso F. Guber R. Guernane B. Guerzoni M. Guilbaud K. Gulbrandsen H. Gulkanyan T. Gunji A. Gupta R. Gupta K. H. Khan R. Haake Ø. Haaland C. Hadjidakis M. Haiduc H. Hamagaki G. Hamar L. D. Hanratty A. Hansen John W. Harris H. Hartmann A. Harton D. Hatzifotiadou S. Hayashi A. Hayrapetyan S. T. Heckel M. Heide H. Helstrup A. Herghelegiu G. Herrera Corral B. A. Hess K. F. Hetland B. Hicks B. Hippolyte J. Hladky P. Hristov M. Huang T. J. Humanic D. Hutter D. S. Hwang J.-C. Ianigro R. Ilkaev I. Ilkiv M. Inaba E. Incani G. M. Innocenti C. Ionita M. Ippolitov M. Irfan M. Ivanov V. Ivanov O. Ivanytskyi A. Jacholkowski C. Jahnke H. J. Jang M. A. Janik P. H. S. Y. Jayarathna S. Jena R. T. Jimenez Bustamante P. G. Jones H. Jung A. Jusko S. Kalcher P. Kalinak A. Kalweit J. Kamin J. H. Kang V. Kaplin S. Kar A. Karasu Uysal O. Karavichev T. Karavicheva E. Karpechev U. Kebschull R. Keidel B. Ketzer M. Mohisin Khan P. Khan S. A. Khan A. Khanzadeev Y. Kharlov B. Kileng B. Kim D. W. Kim D. J. Kim J. S. Kim M. Kim M. Kim S. Kim T. Kim S. Kirsch I. Kisel S. Kiselev A. Kisiel G. Kiss J. L. Klay J. Klein C. Klein-Bösing A. Kluge M. L. Knichel A. G. Knospe C. Kobdaj M. K. Köhler Thorsten Kollegger A. Kolojvari V. Kondratiev N. Kondratyeva A. Konevskikh V. Kovalenko M. Kowalski S. Kox G. Koyithatta Meethaleveedu J. Kral I. Králik F. Kramer A. Kravčáková M. Krelina M. Kretz M. Krivda F. Krizek M. Krus E. Kryshen M. Krzewicki V. Kučera Y. Kucheriaev T. Kugathasan C. Kuhn P. G. Kuijer I. Kulakov J. Kumar P. Kurashvili A. Kurepin A. B. Kurepin A. Kuryakin S. Kushpil V. Kushpil M. J. Kweon Y. Kwon P. Ladron de Guevara C. Lagana Fernandes I. Lakomov R. Langoy C. Lara A. Lardeux A. Lattuca S. L. La Pointe P. La Rocca R. Lea G. R. Lee I. Legrand J. Lehnert R. C. Lemmon M. Lenhardt V. Lenti E. Leogrande M. Leoncino I. León Monzón P. Lévai S. Li J. Lien R. Lietava S. Lindal V. Lindenstruth C. Lippmann M. A. Lisa H. M. Ljunggren D. F. Lodato P. I. Loenne V. R. Loggins V. Loginov D. Lohner C. Loizides X. Lopez E. López Torres X.-G. Lu P. Luettig M. Lunardon J. Luo G. Luparello C. Luzzi A. M. Gago P. M. Jacobs R. Ma A. Maevskaya M. Mager D. P. Mahapatra A. Maire M. Malaev I. Maldonado Cervantes L. Malinina D. Mal’Kevich P. Malzacher A. Mamonov L. Manceau V. Manko F. Manso V. Manzari M. Marchisone J. Mareš G. V. Margagliotti A. Margotti A. Marín C. Markert M. Marquard I. Martashvili N. A. Martin P. Martinengo M. I. Martínez G. Martínez García J. Martin Blanco Y. Martynov A. Mas S. Masciocchi M. Masera A. Masoni L. Massacrier A. Mastroserio A. Matyja C. Mayer J. Mazer R. Mazumder M. A. Mazzoni F. Meddi A. Menchaca-Rocha J. Mercado Pérez M. Meres Y. Miake K. Mikhaylov L. Milano J. Milosevic A. Mischke A. N. Mishra Dariusz Miśkowiec C. M. Mitu J. Mlynarz B. Mohanty L. Molnar L. Montaño Zetina E. Montes M. Morando D. A. Moreira De Godoy S. Moretto A. Morreale A. Morsch V. Muccifora E. Mudnic S. Muhuri M. Mukherjee H. Müller M. G. Munhoz S. Murray L. Musa J. Musinsky B. K. Nandi R. Nania E. Nappi C. Nattrass T. K. Nayak S. Nazarenko A. Nedosekin M. Nicassio M. Niculescu B. S. Nielsen S. Nikolaev S. Nikulin V. Nikulin B. S. Nilsen F. Noferini P. Nomokonov G. Nooren A. Nyanin A. Nyatha J. Nystrand Helmut Oeschler S. Oh S. K. Oh A. Okatan L. Olah J. Oleniacz A. C. Oliveira Da Silva J. Onderwaater C. Oppedisano A. Ortiz Velasquez A. Oskarsson J. Otwinowski K. Oyama Y. Pachmayer M. Pachr P. Pagano G. Paić F. Painke C. Pajares S. K. Pal A. Palmeri D. Pant V. Papikyan G. S. Pappalardo W. J. Park A. Passfeld D. I. Patalakha V. Paticchio B. Paul T. Pawlak T. Peitzmann H. Pereira Da Costa E. Pereira De Oliveira Filho D. Peresunko C. E. Pérez Lara W. Peryt A. Pesci Y. Pestov V. Petráček M. Petran M. Petris M. Petrovici C. Petta S. Piano M. Pikna P. Pillot O. Pinazza L. Pinsky D. B. Piyarathna M. Ploskon M. Planinic J. Pluta S. Pochybova P. L. M. Podesta-Lerma M. G. Poghosyan E. H. O. Pohjoisaho B. Polichtchouk N. Poljak A. Pop S. Porteboeuf-Houssais J. Porter V. Pospisil B. Potukuchi S. K. Prasad R. Preghenella F. Prino C. A. Pruneau I. Pshenichnov G. Puddu P. Pujahari V. Punin J. Putschke H. Qvigstad A. Rachevski S. Raha J. Rak A. Rakotozafindrabe L. Ramello R. Raniwala S. Raniwala S. S. Räsänen B. T. Rascanu D. Rathee A. W. Rauf V. Razazi K. F. Read J. S. Real K. Redlich R. J. Reed A. Rehman P. Reichelt M. Reicher F. Reidt Rainer Ernst Arno Renfordt A. R. Reolon A. Reshetin F. Rettig J.-P. Revol K. Reygers V. Riabov R. A. Ricci T. Richert M. Richter P. Riedler W. Riegler F. Riggi A. Rivetti E. Rocco M. Rodríguez Cahuantzi A. Rodriguez Manso K. Røed E. Rogochaya S. Rohni D. Rohr D. Röhrich R. Romita F. Ronchetti L. Ronflette P. Rosnet S. Rossegger A. Rossi A. Roy C. Roy P. Roy A. J. Rubio Montero R. Rui R. Russo E. Ryabinkin Y. Ryabov A. Rybicki S. Sadovsky K. Šafařík B. Sahlmuller R. Sahoo P. K. Sahu J. Saini C. A. Salgado J. Salzwedel S. Sambyal V. Samsonov X. Sanchez Castro F. J. Sánchez Rodríguez L. Šándor Andres Sandoval M. Sano G. Santagati D. Sarkar E. Scapparone F. Scarlassara R. P. Scharenberg C. Schiaua R. Schicker C. Schmidt H. R. Schmidt S. Schuchmann J. Schukraft M. Schulc T. Schuster Y. Schutz K. Schwarz K. Schweda G. Scioli E. Scomparin P. A. Scott R. Scott G. Segato J. E. Seger I. Selyuzhenkov J. Seo E. Serradilla A. Sevcenco A. Shabetai G. Shabratova R. Shahoyan A. Shangaraev N. Sharma S. Sharma K. Shigaki K. Shtejer Y. Sibiriak S. Siddhanta T. Siemiarczuk D. Silvermyr C. Silvestre G. Simatovic R. Singaraju R. Singh S. Singha V. Singhal B. C. Sinha T. Sinha B. Sitar M. Sitta T. B. Skaali K. Skjerdal R. Smakal N. Smirnov R. J. M. Snellings C. Søgaard R. Soltz J. Song M. Song F. Soramel S. Sorensen M. Spacek I. Sputowska M. Spyropoulou-Stassinaki B. K. Srivastava J. Stachel I. Stan G. Stefanek M. Steinpreis E. Stenlund G. Steyn J. H. Stiller D. Stocco M. Stolpovskiy P. Strmen A. A. P. Suaide M. A. Subieta Vasquez T. Sugitate C. Suire M. Suleymanov R. Sultanov M. Šumbera T. Susa T. J. M. Symons A. Szanto de Toledo I. Szarka A. Szczepankiewicz M. Szymanski J. Takahashi M. A. Tangaro J. D. Tapia Takaki A. Tarantola Peloni A. Tarazona Martinez A. Tauro G. Tejeda Muñoz A. Telesca C. Terrevoli A. Ter Minasyan J. Thäder D. Thomas R. Tieulent A. R. Timmins A. Toia H. Torii V. Trubnikov W. H. Trzaska T. Tsuji A. Tumkin R. Turrisi T. S. Tveter J. Ulery K. Ullaland J. Ulrich A. Uras G. L. Usai M. Vajzer M. Vala L. Valencia Palomo S. Vallero P. Vande Vyvre L. Vannucci J. W. Van Hoorne M. van Leeuwen A. Vargas R. Varma M. Vasileiou A. Vasiliev V. Vechernin M. Veldhoen M. Venaruzzo E. Vercellin S. Vergara Limón R. Vernet M. Verweij L. Vickovic G. Viesti J. Viinikainen Z. Vilakazi O. Villalobos Baillie A. Vinogradov L. Vinogradov Y. Vinogradov T. Virgili Y. P. Viyogi A. Vodopyanov M. A. Völkl K. Voloshin S. A. Voloshin G. Volpe B. von Haller I. Vorobyev D. Vranic J. Vrláková B. Vulpescu A. Vyushin B. Wagner J. Wagner V. Wagner M. Wang Y. Wang D. Watanabe M. Weber J. P. Wessels U. Westerhoff J. Wiechula J. Wikne M. Wilde G. Wilk J. Wilkinson M. C. S. Williams B. Windelband M. Winn C. Xiang C. G. Yaldo Y. Yamaguchi H. Yang P. Yang S. Yang S. Yano S. Yasnopolskiy J. Yi Z. Yin I.-K. Yoo I. Yushmanov V. Zaccolo C. Zach A. Zaman C. Zampolli S. Zaporozhets A. Zarochentsev P. Závada N. Zaviyalov H. Zbroszczyk I. S. Zgura M. Zhalov F. Zhang H. Zhang X. Zhang Y. Zhang C. Zhao D. Zhou F. Zhou Y. Zhou H. Zhu J. Zhu J. Zhu X. Zhu A. Zichichi A. Zimmermann M. B. Zimmermann G. Zinovjev Y. Zoccarato M. Zynovyev M. Zyzak

A measurement of the transverse momentum spectra of jets in Pb-Pb collisions at sNN−−−√=2.76 TeV is reported. Jets are reconstructed from charged particles using the anti-kT jet algorithm with jet resolution parameters R of 0.2 and 0.3 in pseudo-rapidity |η|<0.5. The transverse momentum pT of charged particles is measured down to 0.15 GeV/c which gives access to the low pT fragments of the jet. Jets found in heavy-ion collisions are corrected event-by-event for average background density and on an inclusive basis (via unfolding) for residual background fluctuations and detector effects. A strong suppression of jet production in central events with respect to peripheral events is observed. The suppression is found to be similar to the suppression of charged hadrons, which suggests that substantial energy is radiated at angles larger than the jet resolution parameter R=0.3 considered in the analysis. The fragmentation bias introduced by selecting jets with a high pT leading particle, which rejects jets with a soft fragmentation pattern, has a similar effect on the jet yield for central and peripheral events. The ratio of jet spectra with R=0.2 and R=0.3 is found to be similar in Pb-Pb and simulated PYTHIA pp events, indicating no strong broadening of the radial jet structure in the reconstructed jets with R<0.3.

The ALICE TPC : a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events (2010)

Johan Alme Y. Andres Harald Appelshäuser Sebastian Bablok Norbert Bialas Rikard Bolgen Uwe Bonnes Roland Bramm Peter Braun-Munzinger Roberto Campagnolo Peter Christiansen Alexandru Florin Dobrin Claude Engster Dominik Fehlker Yiota Foka Uli Frankenfeld Jens Joergen Gaardhøje Chilo Garabatos Peter Glässel Carmen Gonzalez Gutierrez Philippe Gros Hans-Åke Gustafsson Haavard Helstrup Michael Hoch Marian Ivanov Rudolf Janik Antoine Junique Alexander Kalweit Ralf Keidel Stefan Kniege Marek Kowalski Dag Toppe Larsen Yannick Lesenechal Philippe Lenoir Niels Lindegaard Christian Lippmann Magnus Mager Manfred Mast Adam Matyja Magne Munkejord Luciano Musa Borge S. Nielsen Vedran Nikolic Helmut Oeschler E.K. Olsen Anders Oskarsson Lennart Osterman Miro Pikna Attiq Ur Rehman Gaël Renault Rainer Ernst Arno Renfordt Stefan Rossegger Dieter Röhrich Ketil Røed Mattias Richter G. Rueshmann Andrzej Rybicki Hans Sann Hans-Rudolf Schmidt Martin Siska Brano Sitár Carsten Soegaard Hans Kristian Soltveit Daniel Soyk Johanna Stachel Herbert Stelzer Evert Anders Stenlund Reinhard Stock Peter Strmeň Imrich Szarka Kjetil Ullaland Danilo Vranic Rob Veenhof Joern Westergaard Jens Wiechula Bernd Stefan Windelband

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb–Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.

Evidence for an exotic S=-2, Q=-2 baryon resonance in proton-proton collisions at the CERN SPS (2004)

Christopher Alt Latchezar Betev Anja Billmeier Christoph Blume Roland Bramm Predrag Buncic Peter Dinkelaker Dominik Bernhard Flierl Marek Gazdzicki Stefan Kniege Thorsten Kollegger Christine Meurer Michael Kosta Mitrovski Rainer Ernst Arno Renfordt Reinhard Stock Herbert Ströbele Alexander Albert Wetzler Jacek Zaranek et al. NA49 Collaboration

Results of resonance searches in the Xi - pi -, Xi - pi +, Xi -bar+ pi -, and Xi -bar+ 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/c2 and width below the detector resolution of about 0.018 GeV/c2. The significance is estimated to be above 4.2 sigma . This state is a candidate for the hypothetical exotic Xi --3/2 baryon with S=-2, I=3 / 2, and a quark content of (dsdsu-bar). At the same mass, a peak is observed in the Xi - pi + spectrum which is a candidate for the Xi 03/2 member of this isospin quartet with a quark content of (dsusd-bar). The corresponding antibaryon spectra also show enhancements at the same invariant mass.

System size and centrality dependence of the balance function in A+A collisions at sqrt[sNN]=17.2 GeV (2005)

Christopher Alt Tome Antičić B. Baatar Daniel Barna Jerzy Bartke Latchezar Betev Helena Białkowska Anja Billmeier Christoph Blume Bożena Boimska Michiel Botje Juraj Bracinik Roland Bramm René Brun Predrag Buncic Vladimir Cerny Panagiotis Christakoglou Ondrej Chvala John G. Cramer Péter Csató Nikolay Darmenov Anton Dimitrov Peter Dinkelaker Volker Eckardt Gerassimos Farantatos Dominik Bernhard Flierl Zoltan Fodor Panagiota Foka P. Freund Volker Friese József Gál Marek Gazdzicki George Georgopoulos Ewa Gładysz-Dziaduś Katarzyna Grebieszkow Sándor Hegyi Claudia Höhne Krešo Kadija A. Karev Michael Kliemant Stefan Kniege Vadim Ivanovith Kolesnikov Thorsten Kollegger Ewelina Kornas Robert Korus M. Kowalski Ingrid Kraus Michal Kreps Marco van Leeuwen Peter Lévai Leandr Litov Benjamin Lungwitz Martin Makariev Aleksandr I. Malakhov Christina Markert Matey Mateev Bill W. Mayes Gueordi L. Melkumov Christine Meurer André Mischke Michael Mitrovski J. Molnár Stanislaw Mrówczyński Gabriella Pálla Apostolos D. Panagiotou Dimitar Panayotov Athanasios Petridis Miro Pikna Lawrence Pinsky Falk Pühlhofer Jeffrey G. Reid Rainer Ernst Arno Renfordt A. Richard Christof Roland Gunther Roland Maciej Rybczynski Andrzej Rybicki Andres Sandoval Hans Sann Norbert Schmitz Peter Seyboth Ferenc Siklér Branislav Sitar Ewa Skrzypczak Grzegorz Stefanek Reinhard Stock Herbert Ströbele Tatjana Susa Imre Szentpétery János Sziklai Victor Trubnikov Dezso Varga Maria Vassiliou Gábor Veres Gyoergy Vesztergombi Danilo Vranic Alexander Albert Wetzler Zbigniew Włodarczyk In-Kwon Yoo Jacek Zaranek József Zimányi

Electric charge correlations were studied for p+p, C+C, Si+Si, and centrality selected Pb+Pb collisions at sqrt[sNN]=17.2 GeV with the NA49 large acceptance detector at the CERN SPS. In particular, long-range pseudorapidity correlations of oppositely charged particles were measured using the balance function method. The width of the balance function decreases with increasing system size and centrality of the reactions. This decrease could be related to an increasing delay of hadronization in central Pb+Pb collisions.

Charged particle spectra in central S+S collisions at 200 GeV/c per nucleon (1994)

J. Eschke M. Fuchs Marek Gazdzicki W. Heck S. Kabana A. Kühmichel M. Lahanas J. Y. Lee Rainer Ernst Arno Renfordt D. Röhrich G. Roland H. Rothard I. Schneider Reinhard Stock Herbert Ströbele S. Wenig

The transverse momentum and rapidity distributions of negative hadrons and participant protons have been measured for central 32S+ 32S collisions at plab=200 GeV/c per nucleon. The proton mean rapidity shift < Delta y>~1.6 and mean transverse momentum <pT>~0.6 GeV/c are much higher than in pp or peripheral AA collisions and indicate an increase in the nuclear stopping power. All pT spectra exhibit similar source temperatures. Including previous results for K0s Lambda , and Lambda -bar, we account for all important contributions to particle production.

Pion production in high-energy nucleus-nucleus collisions (1987)

John W. Harris Grazyna Odyniec Howel G. Pugh Lee S. Schroeder Mark L. Tincknell Wolfgang Rauch Reinhard Stock Rudolf Bock Robert Brockmann Andres Sandoval Herbert Ströbele Rainer Ernst Arno Renfordt Dietmar Schall Dieter Bangert John P. Sullivan Kevin L. Wolf Ángel Dacal C. Guerra Maria Esther Ortiz

Collective motion in nucleus-nucleus collisions at 800 MeV/nucleon (1988)

Pawel Danielewicz Herbert Ströbele Grazyna Odyniec Dietmar Bangert Rudolf Bock Robert Brockmann John W. Harris Howel G. Pugh Wolfgang Rauch Rainer Ernst Arno Renfordt Andres Sandoval Dietmar Schall Lee S. Schroeder Reinhard Stock

Semicentral Ar+KCl, La+La, and Ar+Pb collisions at 800 MeV/nucleon were studied using a streamer chamber. The results are analyzed in the framework of the transverse momentum analysis and in terms of the average sphericity matrix. A critical examination of the analysis procedures, both experimental and theoretical, is given. New procedures are described to account for overall momentum conservation in the reaction, and to correct for azimuthal variations in the detection efficiency. Average transverse momenta per nucleon in the reaction plane are presented for deuterons emitted in the forward hemisphere, as these provide the most reliable information. A Vlasov-Uehling-Uhlenbeck calculation with a stiff equation of state gives a good fit to the momenta in the Ar+Pb reaction. Flow effects parametrized further using the sphericity tensor are found stronger than in the cascade model and consistently weaker than predicted by hydrodynamics. Parameters from the sphericity tensor exhibit a larger variation as a function of multiplicity than do the average momenta per nucleon.

Collective motion in Ar+Pb collision at beam energies between 400 and 1800 MeV/nucleon (1992)

Dana Richard Beavis Rudolf Bock Robert Brockmann Pawel Danielewicz Sun-Yiu Fung John W. Harris Declan Keane Y. M. Liu Grazyna Odyniec Howel G. Pugh Rainer Ernst Arno Renfordt Andres Sandoval Dietmar Schall Lee S. Schroeder Reinhard Stock Herbert Ströbele M. A. Vient

The energy dependence of rapidity distributions and flow effects was studied in central Ar+Pb collisions at 400, 800, and 1800 MeV/nucleon using a streamer chamber. Rapidity distributions for proton and pions are found to have a Gaussian shape whereas those for deuterons exhibit a two-peak structure at the two higher energies. The average in-plane transverse momentum per/nucleon and per/event shows saturation of flow around 800 MeV/nucleon for this asymmetric system. The aspect ratio of the sphericity tensor is closely correlated with the flow angle. This correlation appears to be independent of beam energy. The number of participating nucleons in central collisions varies from 213 at 400 to 135 at 1800 MeV/nucleon indicating that at the lowest energy almost the entire target nucleus participates in the collision.

Pion and proton "temperatures" in relativistic heavy-ion reactions (1984)

Robert Brockmann John W. Harris Andres Sandoval Reinhard Stock Herbert Ströbele Grazyna Odyniec Howel G. Pugh Lee S. Schroeder Rainer Ernst Arno Renfordt Dietmar Schall Dieter Bangert Wolfgang Rauch Kevin L. Wolf

Pion and proton production are measured to investigate thermal equilibrium in central collisions of 40Ar+KCl at 1.8 GeV/nucleon. The bulk of the pion yield is isotropic in the c.m. system, with an apparent temperature of 58±3 MeV, much lower than the 118±2 MeV of the protons. It is shown that the low pion "temperature" can be explained by the decay kinematics of delta resonances in thermal equilibrium. A (5±1)% component in the pion spectrum is, however, found to have a temperature of 110±10 MeV. The effect on the spectra of possible contributions from collective radial flow is discussed.

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