Photon-hadron jet correlations inp+pandAu+Aucollisions atsNN=200GeV

A Adare,S Kametani,K Okada,M Gonin,P Tarján,S D Rolnick,M Stepanov,Y Watanabe,A Enokizono,S Mioduszewski,R Averbeck,I Tserruya,C Vale,D Walker,M Germain,E Kistenev,K Hasuko,H W Van Hecke,F Staley,R P Pisani,L Kochenda,H Hamagaki,M Mitrovski,T K Shea,S Zhou,R K Choudhury,A A Bickley,N Kurihara,K Nakano,R Yang,H Valle,X R Wang,W C Chang,L Baksay,I Shein,Y Onuki,R S Towell,I Nakagawa,T Shohjoh,S K Tuli,I J Choi,H Buesching,Y Fukao,R Seto,H Qu,A Baldisseri,A K Mohanty,V Riabov,Y Nagata,S Kelly,D Roach,Y Miake,M Inaba,O Drapier,P Shukla,Y Cobigo,A Deshpande,K Reygers,K M Kijima,A Hadj Henni,D Ivanischev,D S Brown,J Park,K Fujiwara,T Sato,F Gastineau,K Boyle,C Haegemann,W C Smith,J E Frantz,M Csanád,H Hiejima,T Fusayasu,V Papavassiliou,V Baublis,P Constantin,V Samsonov,D Jouan,J Alexander,K F Read,X He,K Shoji,A Soldatov,W S Emam,T K Hemmick,Y Akiba,H Delagrange,B Espagnon,J Kubart,J Ying,M L Purschke,C Zhang,K Sedgwick,J M Moss,M J Leitch,M Kaneta,H Borel,I Ravinovich,T Horaguchi,V Bumazhnov,B M Johnson,K S Joo,W Holzmann,A Bazilevsky,J Nystrand,M X Liu,K S Sim,R Seidl,I V Sourikova,M Ishihara,M Hohlmann,B Fadem,D Dutta,T Hester,G Baksay,V Cianciolo,K Dehmelt,D Isenhower,H Lim,A Isupov,J Koster,R Tanabe,D Layton,Z Fraenkel,D Silvermyr,I Younus,I E Yushmanov,G C Mishra,D E Fields,E Kinney,L Mašek,H Masui,T Liška,J Imrek,Y V Efremenko,P Liebing,A D Frawley,D J Kim,A Kravitz,K Shigaki,P Mikeš,B Lenzi,R Ichimiya,A Drees,B Komkov,K Haruna,K Miki,A Denisov,M Shimomura,K Sakashita,C L Woody,T Niita,E J Desmond,M G Hur,S Takagi,Y Kwon,M Oka,T Kawagishi,J Jin,J Kamin,J Murata,T Sakaguchi,N Tyurin,M Holmes,M T Bjorndal,W Xie,D Winter,E Haslum,Z Yasin,K Kiriluk,V Pantuev,Y Morino,A K Dubey,J Chiba,M Reuter,A Glenn,R A Soltz,E T Atomssa,E Kim,N Saito,S Leckey,B Sahlmueller,T Gunji,P Rukoyatkin,T Nakamura,J P Sullivan,P J Kroon,S Huang,T V Moukhanova,T Isobe,I D Ojha,Y Inoue,J Velkovska,A Sukhanov,D Sharma,Y Nakamiya,S Gadrat,S Sawada,M D Malik,E P Hartouni,A Malakhov,M Mishra,S Bathe,A Ster,H Al-Bataineh,Y Mao,J Newby,M Finger,K Yamaura,A Lebedev,L Zolin,M K Lee,S Campbell,T Dahms,J M Burward-Hoy,K O Eyser,T Ichihara,A Churyn,P Chung,A Taketani,D H Kim,M Rosati,T Chujo,D Bucher,G J Kunde,F Ellinghaus,R Pak,V Kochetkov,P W Stankus,C Silvestre,J Sziklai,S Rembeczki,M J Tannenbaum,T Tabaru,J Kapustinsky,K Das,D M Lee,F Wei,B K Singh,J Seele,J T Mitchell,L Tomášek,T Hachiya,E M Takagui,A Durum,L Isenhower,K Tanida,I Garishvili,V Peresedov,G Bunce,A Franz,M Konno,O Zaudtke,C A Ogilvie,H Liu,K Kurita,B Hong,Y Le Bornec,R Hobbs,T C Awes,X Li,T Lee,D Kawall,M Connors,F Matathias,S Batsouli,J L Nagle,I Otterlund,H Tydesjö,S Butsyk,B Azmoun,B Forestier,V Vrba,M L Brooks,A V Kazantsev,H Pereira,S F Pate,K B Lee,T L Thomas,R Lacey,M Heffner,H Sakata,A Kozlov,S H Kim,K A Drees,C Pinkenburg,S Sakai,D Mukhopadhyay,R Hayano,M I Nagy,J Asai,M J Kweon,M Togawa,N Kamihara,A Dion,Y Ikeda,G S Kyle,M A L Leite,M Ouchida,O Dietzsch,D Pal,V Babintsev,M Chiu,A Veicht,A Taranenko,F Bauer,A Toia,S S Ryu,Y Tsuchimoto,B Love,Y S Lai,Y Tanaka,J Zimányi,K Imai,W E Sondheim,M P Comets,J Rak,V Semenov,A Khanzadeev,T Sugitate,P D Barnes,C P Singh,E Stenlund,G R Young,S Chernichenko,B Bassalleck,J H Kang,M C Mccain,T E Miller,A K Purwar,J C Hill,D Lynch,C Baumann,Y I Makdisi,M Kurosawa,H Themann,Y Berdnikov,H Gong,F Fleuret,A Yanovich,H Torii,M Mccumber,E Mannel,N Willis,O Jinnouchi,W A Zajc,K Homma,W J Park,D Kotchetkov,J G Boissevain,V L Rykov,S P Stoll,J L Drachenberg,S Nagamiya,D Yu Peressounko,H Okada,P L Mcgaughey,X H Li,M Donadelli,N N Ajitanand,S Esumi,O O Omiwade,M Naglis,A Romana,A Kiyomichi,B Meredith,S Dairaku,M Virius,E Vznuzdaev,Y Riabov,M Issah,N Means,J Egdemir,R Nouicer,S Afanasiev,M Wysocki,K Ozawa,J M Heuser,S Skutnik,A Berdnikov,M Slunečka,M B Deaton,C L Silva,S Yokkaichi,F Kajihara,A Morreale,V Dzhordzhadze,R Han,T Kempel,J S Haggerty,N Grau,A Al-Jamel,J Jia,A Litvinenko,S H Aronson,M Nguyen,B I Kim,M Harvey,G Roche,C R Cleven,C Suire,A Král,J Tojo,G David,A Milov,J G Lajoie,D P Morrison,K N Barish,A Shevel,P Rosnet,A Rakotozafindrabe,Y Goto,R Bennett,H Pei,R Granier De Cassagnac,T Engelmore,D Hornback,M Grosse Perdekamp,L Aphecetche,C A Aidala ,B Norman ,С Беликов ,R Vértesi ,Á Kiss ,J S Chai ,H Sato ,S Fokin ,T Csörgõ ,Susumu Sato ,S Sörensen ,B Jacak ,C Maguire ,A Semenov ,J C Peng ,T A Shibata ,Jun Kikuchi ,Yasuhiro Tomita ,V Manko ,H En’yo ,Kazuo Aoki ,S S.e Rosendahl ,S White ,J P Wessels ,Mathias Wagner ,A Öskarsson ,S Greene ,Hideaki Kano ,A Basye ,B Chang ,S Oda ,B Cole ,Hiroyuki Harada ,S Y Fung ,E O’brien ,J L Klay ,H Å Gustafsson ,Mei Bai ,Christian Klein-Boesing ,Masayuki Hagiwara ,А Виноградов ,A Nyanin ,Z H Citron ,Y S Kim ,Kazuhiro Tanaka ,C H Chen ,V N Tram ,V K Singh ,H Ohnìshì ,A M Sickles ,R Arméndariz ,C Y ,C Muñoz Camacho ,J Gösset ,A P.t Palounek ,Y Yamaguchi ,D D’enterria ,P Růžička ,J L Charvet

doi:10.1103/physrevc.80.024908

Abstract

We report the observation at the Relativistic Heavy Ion Collider (RHIC) of suppression of back-to-back correlations in the direct photon+jet channel in Au+Au relative to p+p collisions. Two-particle correlations of direct photon triggers with associated hadrons are obtained by statistical subtraction of the decay photon-hadron background. The initial momentum of the away-side parton is tightly constrained, because the parton-photon pair exactly balance in momentum at leading order in perturbative quantum chromodynamics (pQCD), making such correlations a powerful probe of the in-medium parton energy loss. The away-side nuclear suppression factor, I_AA, in central Au+Au collisions, is 0.32 +/- 0.12(stat) +/- 0.09(syst) for hadrons of 3 < p_T < 5 in coincidence with photons of 5 < p_T < 15 GeV/c. The suppression is comparable to that observed for high-p_T single hadrons and dihadrons. The direct photon associated yields in p+p collisions scale approximately with the momentum balance, z_T = p_T^hadron/p_T^photon, as expected for a measure of the away-side parton fragmentation function. We compare to Au+Au collisions for which the momentum balance dependence of the nuclear modification should be sensitive to the path-length dependence of parton energy loss.

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