Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

L Adamczyk,A Ohlson,E Sangaline,J Konzer,T D S Stanislaus,J H Chen,P V Shanmuganathan,C Markert,J Butterworth,C K Riley,P Djawotho,H W Ke,Y Xu,D Cebra,J H Thomas,D Solanki,M A Lisa,M M Aggarwal,S Heppelmann,A R Timmins,T Pawlak,F Liu,C Li,G Nigmatkulov,H F Chen,R Haque,J K Adkins,Y Pandit,S Kabana,G Van Nieuwenhuizen,Md Nasim,R Bellwied,P Chaloupka,K D Landry,J Seger,T P Burton,P Yepes,L C Bland,D N Svirida,N Schmitz,A V Brandin,M Tokarev,R Fatemi,L G Efimov,Y Panebratsev,G W Hoffmann,X Li,J Bouchet,N Yu,W Borowski,H Masui,Y X Pan,A Aparin,J Lauret,P Bhattarai,X L Wang,R S Longacre,C Dilks,H Bichsel,A A Derevschikov,P K Sahu,J R Stevens,G Eppley,A Quintero,J E Draper,H Z Huang,S Horvat,S Zhang,I Koralt,L Didenko,J Takahashi,W Peryt,J Putschke,D Mcdonald,D P Mahapatra,K Xin,S Raniwala,Y Zoulkarneeva,Y Fisyak,W B Schmidke,H Wieman,B Sharma,R P Scharenberg,Y Zhang,B Pawlik,E C Aschenauer,D J Hofman,X Cui,J G Cramer,J H Lee,S K Pal,J S Wang,S Mioduszewski,L Greiner,Y Li,W Christie,G Contin,T S Mcshane,P Pile,A Hirsch,M J Skoby,A M Poskanzer,A Vossen,H M Spinka,B Surrow,R Majka,J L Romero,S G Brovko,Y Sun,M J M Codrington,W Guryn,D Arkhipkin,O D Tsai,A Gibson,B Di Ruzza,J M Nelson,R Stock,G D Westfall,D Tlusty,W J Llope,D Keane,J Zhao,A Sarkar,R Raniwala,N Xu,J Porter,K S Engle,M Calderón De La Barca Sánchez,V Okorokov,R A Kycia,N G Minaev,P Huck,S Salur,J C Dunlop,S Ramachandran,G S Averichev,A Kechechyan,E Shahaliev,A Lebedev,M Cherney,T Ullrich,O Eyser,G Webb,K Kang,S Chattopadhyay,A Roy,L K Kosarzewski,G Wang,X Huang,L Yi,A Ogawa,J B Zhang,M Vandenbroucke,L C De Silva,A Gupta,J A Vanfossen,I Kulakov,J Pluta,A H Tang,L E Dunkelberger,J Turnau,W Xie,S Dhamija,E Finch,T Tarnowsky,X Zhu,A Chikanian,M K Mustafa,Y Wang,O V Rogachevskiy,L V Nogach,M Shao,M M Mondal,J F Ross,H Caines,S S Shi,H Wang,I Bunzarov,B Srivastava,M J Levine,P Filip,W Li,S Trentalange,M Strikhanov,J Cheng,B K Nandi,P Sorensen,B A Trzeciak,E G Judd,D Grosnick,D G Underwood,X Luo,Z Chang,C Perkins,Q H Xu,X Dong,S Fazio,M C Cervantes,I G Bordyuzhin,T Kollegger,W Zha,A Banerjee,R L Ray,D Garand,Z M Li,D S Gunarathne,J Engelage,G Van Buren,S Gliske,J Schambach,N Smirnov,H Zbroszczyk,B Stringfellow,Z Ahammed,L Chen,D R Gangadharan,Y Zawisza,M Lomnitz,X P Zhang,H J Crawford,J M Landgraf,K Poniatowska,H Pei,J Alford,J C Webb,S W Wissink,O Rusnakova,K Kauder,N Poljak,D M M D Madagodagettige Don,F Ding,I Sakrejda,H S Matis,B Mohanty,B Huang,A Kisiel,S Das,D Smirnov,G Igo,W Q Shen,S B Nurushev,Z Ye,D Kalinkin,A K Bhati,Y P Viyogi,T G Dedovich,G Agakishiev,A Kesich,S Bültmann,Z P Zhang,R Witt,K Oh,C A Gagliardi,J L Zhang,S Gupta,G Odyniec,I Alekseev,H Qiu,P Tribedy,N Shah,Y Guo,L Kumar,A F Kraishan,L Kotchenda,R Derradi De Souza,T J M Symons,E P Sichtermann,B Haag,J L Drachenberg,Z Sun,N K Pruthi,K Krueger,B S Page,P R Pujahari,S Margetis,O Evdokimov,J W Harris,M Pachr,Z Tang,A Hamed,S Y Noh,I Kisel,L Eun,T K Nayak,F Wang,R Cendejas,M Wada,J Sandweiss,E W Oldag,K Yip,Z Xu,M Zyzak,A Bhasin,F Videbæk,T J Humanic,Z H Khan,A Davila Leyva,R Varma,C M Du,X M Sun,L Ruan,J Deng,R E Tribble,A M Schmah,W W Jacobs,P Seyboth,D D Koetke,H S Xu ,M Przybycień ,D Olvitt ,M A.c Lamont ,D P Kikoła ,A Vasiliev ,M Fusco Girard ,Jun Xu ,J Fedorišin ,J Rusňák ,Feng Zhao ,Y G ,D Beavis ,П Кравцов ,J Novák ,S Vokál ,J Bielčíková ,Y Zhu ,C Flores ,Д А Морозов ,T Ljubičić ,Xiao Zhang ,Michal Szelezniak ,R Debbe ,H J Jang ,R Singaraju ,I K Yoo ,C B Yang ,C Anson ,J Bielčík ,Yan Wang ,G L ,J J Chwastowski ,M Planinić ,R Vértesi ,G M.s Vasconcelos ,F J M Geurts ,H.g Ritter ,Q Shou ,N Sahoo ,L Han ,Y Wu ,R Lednický ,Yang Yu ,M Šumbera ,J Roberts ,Zhong Chen

doi:10.1103/physrevc.92.014904

Abstract

We present results of analyses of two-pion interferometry in Au+Au collisions at sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown–Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.21 MoreReceived 30 January 2015DOI:https://doi.org/10.1103/PhysRevC.92.014904©2015 American Physical Society

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