Nuclear-modification factor of charged hadrons at forward and backward rapidity in p + Al and p + Au collisions at sNN=200GeV

C A Aidala ,C Nattrass,J Perry,R Seto,K Sedgwick,K Kurita,A D Frawley,B Kurgyis,B K Schmoll,M Rosati,A Yanovich,A Dion,S Y Han,B Azmoun,S Lee,T Sakaguchi,I Tserruya,K Dehmelt,J Sziklai,A Iordanova,V Riabov,A Bazilevsky,M X Liu,I Nakagawa,I J Choi,M Kim,R Petti,X He,M J Leitch,A Sukhanov,G David,C P Wong,H W Van Hecke,N Hotvedt,C A Ogilvie,S Hasegawa,Iu Mitrankov,W J Metzger,A Hodges,J Hanks,B M Johnson,R S Towell,J Huang,H Guragain,H Yu,P L Mcgaughey,C Mckinney,S Nelson,R A Soltz,K N Barish,Y Fukuda,A Sen,T Sumita,K Nakano,M Patel,V Papavassiliou,S D Rolnick,M Mccumber,Y I Makdisi,D K Mishra,C E Perezlara,M J Skoby,A Khanzadeev,M Shimomura,J Runchey,R Belmont,I V Sourikova,S Tarafdar,K Deblasio,D Jouan,S Bathe,Y Riabov,C Gal,H F Hamilton,K A Drees,J D Orjuela Koop,N Novitzky,K Nagashima,D Lynch,D S Jumper,Y Berdnikov,M I Nagy,N Cronin,D Kincses,G D N Perera,R P Pisani,I Shein,T Hoshino,S Zharko,H Ge,P Kline,N Feege,L Zou,D Kawall,R Cervantes,B Schaefer,M Mendoza,S Campbell,S F Pate,A Pun,M Snowball,M L Brooks,S Yalcin,D Sharma,A Durum,R Seidl,R Nishitani,M J Tannenbaum,J L Nagle,X Jiang,X Li,V Khachatryan,W Fan,D Ivanishchev,P V Radzevich,T W Danley,A Milov,C Kim,M L Purschke,J C Hill,D P Morrison,T Majoros,B Fadem,A Denisov,A Enokizono,P W Stankus,A Berdnikov,K Imai,J H Kang,B Hong,Z Rowan,R S Hollis,N Grau,A Drees,M Chiu,K I Hahn,A Sexton,W A Zajc,A Taranenko,T Koblesky,J Murata,S I Morrow,J D Osborn,F Giordano,S Esumi,V Bumazhnov,J S Haggerty,D Richford,E J Desmond,R Tieulent,T Moon,T Todoroki,A Deshpande,D Silvermyr,A V Kazantsev,M Sarsour,T O S Haseler,V.-R Loggins,V Vrba,M Finger,J Sun,A Franz,Y Goto,D Reynolds,T Niida,K Tanida,D Isenhower,C L Towell,N Apadula,P Garg,P Montuenga,Y Ueda,Y Akiba,M Virius,N A Lewis,H Hamagaki,A Khatiwada,C P Singh,T K Hemmick,D E Fields,A Timilsina,S Mizuno,T Murakami,T Novák,S H Lee,N Vukman,V Babintsev,W E Sondheim,V Canoa Roman,I Yoon,D Kotov,C Pinkenburg,J E Frantz,E A Gamez,M Makek,L Xue,S Karthas,A Lebedev,I E Yushmanov,M Grosse Perdekamp,M Jezghani,N S Bandara,W Peng,M Beaumier,T Hachiya,S Suzuki,V Andrieux,S P Stoll,Y Kwon,G Mitsuka,T Shioya,J Bryslawskyj,P Shukla,D Kapukchyan,M Slunečka,J Klatsky,R Nouicer,G Tarnai,J G Lajoie,E Kistenev,C L Silva,A C Mignerey,S Miyasaka,M Tomášek,T Gunji,S Kudo,A Zelenski,V Pantuev,Z H Citron ,J M Durham,T Csörgõ ,Hiroshi Yamamoto ,A Safonov ,Y H Leung,A Öskarsson ,Y Watanabe ,D Yu Peressounko ,M Connors,K F Read,E.-J Kim,Z Wang,K Lovász ,B Ujvári ,D Blau ,K Shigaki,Jeongsu Bok ,Z Sun,T Nagashima,C Y ,X R Wang,B Jacak ,K Smith ,S Fokin ,H En’yo ,H Sako,J Velkovska,Sanghoon Lim ,Z Ji,M Daugherity ,J Yoo ,Timothy Thomas Rinn ,D V Perepelitsa,K Ozawa,J Choi ,J H ,K Homma,Y Yamaguchi ,Qingyang Xu ,M W Phipps ,J S Park,B K Singh,Soren Pontoppidan Sorensen ,S Lökòs ,Dhruv Utpalkumar Dixit ,M Csanád,K K Hill ,S Park,S Ishimaru,S Greene ,C Scarlett ,A Nyanin ,G J Ottino,C Woody ,M Alfred,E O’brien ,A M Sickles ,V Manko ,M Inaba,Y Zhai,J T Mitchell,V K Singh ,V Samsonov,T Sugitate,C J Xu ,P Gallus,K Nagai,E Mannel,T A Shibata ,H Asano,S Huang,D Mcglinchey,Susumu Sato

doi:10.1103/physrevc.101.034910

Abstract

The PHENIX experiment has studied nuclear effects in $p$$+$Al and $p$$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV on charged hadron production at forward rapidity ($1.4<\eta<2.4$, $p$-going direction) and backward rapidity ($-2.2<\eta<-1.2$, $A$-going direction). Such effects are quantified by measuring nuclear modification factors as a function of transverse momentum and pseudorapidity in various collision multiplicity selections. In central $p$$+$Al and $p$$+$Au collisions, a suppression (enhancement) is observed at forward (backward) rapidity compared to the binary scaled yields in $p$+$p$ collisions. The magnitude of enhancement at backward rapidity is larger in $p$$+$Au collisions than in $p$$+$Al collisions, which have a smaller number of participating nucleons. However, the results at forward rapidity show a similar suppression within uncertainties. The results in the integrated centrality are compared with calculations using nuclear parton distribution functions, which show a reasonable agreement at the forward rapidity but fail to describe the backward rapidity enhancement.

Highlights

Measurements of particle production in heavy-ion collisions enable the study of properties of a hot and dense nuclear medium called the quark-gluon plasma (QGP) [1,2,3,4]
We present nuclear modification factors of charged hadron in p + Al and production at forward p + Au collisions at a√ndsNbNa=ckw20a0rd rapidity GeV of various multiplicities
There is no significant modification of charged hadron production observed in peripheral p + Al and p + Au collisions in either rapidity region

Summary

Introduction

Measurements of particle production in heavy-ion collisions enable the study of properties of a hot and dense nuclear medium called the quark-gluon plasma (QGP) [1,2,3,4]. An initial striking observation at the Relativistic Heavy Ion Collider (RHIC) was that production of high transverse momentum (pT ) hadrons in Au + Au collisions is strongly suppressed compared to that in p + p collisions scaled by the number of binary collisions. This suppression indicates that partons experience substantial energy loss as they traverse the QGP, a phenomenon called jet-quenching [5]. A control experiment involving a deuteron projectile on a heavy-ion target, d + Au, was carried out to test whether the feature of strong energy loss is still present in a collision system of much smaller size. In the ten years because these initial measurements, indications of QGP formation in smaller collision systems including d + Au have been found, though without evidence of jet quenching phenomena [7]

Methods

Results

Conclusion