Enhanced production of direct photons in Au + Au collisions at square root(S(NN)) = 200 GeV and implications for the initial temperature

A Adare; S Afanasiev; C Aidala; N N Ajitanand; Y Akiba; H Al-Bataineh; J Alexander; A Al-Jamel; K Aoki; L Aphecetche; R Armendariz; S H Aronson; J Asai; E T Atomssa; R Averbeck; T C Awes; B Azmoun; V Babintsev; G Baksay; L Baksay; A Baldisseri; K N Barish; P D Barnes; B Bassalleck; S Bathe; S Batsouli; V Baublis; F Bauer; A Bazilevsky; S Belikov; R Bennett; Y Berdnikov; A A Bickley; M T Bjorndal; J G Boissevain; H Borel; K Boyle; M L Brooks; D S Brown; D Bucher; H Buesching; V Bumazhnov; G Bunce; J M Burward-Hoy; S Butsyk; S Campbell; J-S Chai; B S Chang; J-L Charvet; S Chernichenko; J Chiba; C Y Chi; M Chiu; I J Choi; T Chujo; P Chung; A Churyn; V Cianciolo; C R Cleven; Y Cobigo; B A Cole; M P Comets; P Constantin; M Csanád; T Csörgo; T Dahms; K Das; G David; M B Deaton; K Dehmelt; H Delagrange; A Denisov; D d'Enterria; A Deshpande; E J Desmond; O Dietzsch; A Dion; M Donadelli; J L Drachenberg; O Drapier; A Drees; A K Dubey; A Durum; V Dzhordzhadze; Y V Efremenko; J Egdemir; F Ellinghaus; W S Emam; A Enokizono; H En'yo; B Espagnon; S Esumi; K O Eyser; D E Fields; M Finger; M Finger Jr; F Fleuret; S L Fokin; B Forestier; Z Fraenkel; J E Frantz; A Franz; A D Frawley; K Fujiwara; Y Fukao; S-Y Fung; T Fusayasu; S Gadrat; I Garishvili; F Gastineau; M Germain; A Glenn; H Gong; M Gonin; J Gosset; Y Goto; R Granier de Cassagnac; N Grau; S V Greene; M Grosse Perdekamp; T Gunji; H-A Gustafsson; T Hachiya; A Hadj Henni; C Haegemann; J S Haggerty; M N Hagiwara; H Hamagaki; R Han; H Harada; E P Hartouni; K Haruna; M Harvey; E Haslum; K Hasuko; R Hayano; M Heffner; T K Hemmick; T Hester; J M Heuser; X He; H Hiejima; J C Hill; R Hobbs; M Hohlmann; M Holmes; W Holzmann; K Homma; B Hong; T Horaguchi; D Hornback; M G Hur; T Ichihara; K Imai; M Inaba; Y Inoue; D Isenhower; L Isenhower; M Ishihara; T Isobe; M Issah; A Isupov; B V Jacak; J Jia; J Jin; O Jinnouchi; B M Johnson; K S Joo; D Jouan; F Kajihara; S Kametani; N Kamihara; J Kamin; M Kaneta; J H Kang; H Kanou; T Kawagishi; D Kawall; A V Kazantsev; S Kelly; A Khanzadeev; J Kikuchi; D H Kim; D J Kim; E Kim; Y-S Kim; E Kinney; A Kiss; E Kistenev; A Kiyomichi; J Klay; C Klein-Boesing; L Kochenda; V Kochetkov; B Komkov; M Konno; D Kotchetkov; A Kozlov; A Král; A Kravitz; P J Kroon; J Kubart; G J Kunde; N Kurihara; K Kurita; M J Kweon; Y Kwon; G S Kyle; R Lacey; Y-S Lai; J G Lajoie; A Lebedev; Y Le Bornec; S Leckey; D M Lee; M K Lee; T Lee; M J Leitch; M A L Leite; B Lenzi; H Lim; T Liska; A Litvinenko; M X Liu; X Li; X H Li; B Love; D Lynch; C F Maguire; Y I Makdisi; A Malakhov; M D Malik; V I Manko; Y Mao; L Masek; H Masui; F Matathias; M C McCain; M McCumber; P L McGaughey; Y Miake; P Mikes; K Miki; T E Miller; A Milov; S Mioduszewski; G C Mishra; M Mishra; J T Mitchell; M Mitrovski; A Morreale; D P Morrison; J M Moss; T V Moukhanova; D Mukhopadhyay; J Murata; S Nagamiya; Y Nagata; J L Nagle; M Naglis; I Nakagawa; Y Nakamiya; T Nakamura; K Nakano; J Newby; M Nguyen; B E Norman; A S Nyanin; J Nystrand; E O'Brien; S X Oda; C A Ogilvie; H Ohnishi; I D Ojha; H Okada; K Okada; M Oka; O O Omiwade; A Oskarsson; I Otterlund; M Ouchida; K Ozawa; R Pak; D Pal; A P T Palounek; V Pantuev; V Papavassiliou; J Park; W J Park; S F Pate; H Pei; J-C Peng; H Pereira; V Peresedov; D Yu Peressounko; C Pinkenburg; R P Pisani; M L Purschke; A K Purwar; H Qu; J Rak; A Rakotozafindrabe; I Ravinovich; K F Read; S Rembeczki; M Reuter; K Reygers; V Riabov; Y Riabov; G Roche; A Romana; M Rosati; S S E Rosendahl; P Rosnet; P Rukoyatkin; V L Rykov; S S Ryu; B Sahlmueller; N Saito; T Sakaguchi; S Sakai; H Sakata; V Samsonov; H D Sato; S Sato; S Sawada; J Seele; R Seidl; V Semenov; R Seto; D Sharma; T K Shea; I Shein; A Shevel; T-A Shibata; K Shigaki; M Shimomura; T Shohjoh; K Shoji; A Sickles; C L Silva; D Silvermyr; C Silvestre; K S Sim; C P Singh; V Singh; S Skutnik; M Slunecka; W C Smith; A Soldatov; R A Soltz; W E Sondheim; S P Sorensen; I V Sourikova; F Staley; P W Stankus; E Stenlund; M Stepanov; A Ster; S P Stoll; T Sugitate; C Suire; J P Sullivan; J Sziklai; T Tabaru; S Takagi; E M Takagui; A Taketani; K H Tanaka; Y Tanaka; K Tanida; M J Tannenbaum; A Taranenko; P Tarján; T L Thomas; M Togawa; A Toia; J Tojo; L Tomásek; H Torii; R S Towell; V-N Tram; I Tserruya; Y Tsuchimoto; S K Tuli; H Tydesjö; N Tyurin; C Vale; H Valle; H W van Hecke; J Velkovska; R Vertesi; A A Vinogradov; M Virius; V Vrba; E Vznuzdaev; M Wagner; D Walker; X R Wang; Y Watanabe; J Wessels; S N White; N Willis; D Winter; C L Woody; M Wysocki; W Xie; Y L Yamaguchi; A Yanovich; Z Yasin; J Ying; S Yokkaichi; G R Young; I Younus; I E Yushmanov; W A Zajc; O Zaudtke; C Zhang; S Zhou; J Zimányi; L Zolin; PHENIX Collaboration

doi:10.1103/PhysRevLett.104.132301

Enhanced production of direct photons in Au + Au collisions at square root(S(NN)) = 200 GeV and implications for the initial temperature

Phys Rev Lett. 2010 Apr 2;104(13):132301. doi: 10.1103/PhysRevLett.104.132301. Epub 2010 Mar 29.

Authors

A Adare¹, S Afanasiev, C Aidala, N N Ajitanand, Y Akiba, H Al-Bataineh, J Alexander, A Al-Jamel, K Aoki, L Aphecetche, R Armendariz, S H Aronson, J Asai, E T Atomssa, R Averbeck, T C Awes, B Azmoun, V Babintsev, G Baksay, L Baksay, A Baldisseri, K N Barish, P D Barnes, B Bassalleck, S Bathe, S Batsouli, V Baublis, F Bauer, A Bazilevsky, S Belikov, R Bennett, Y Berdnikov, A A Bickley, M T Bjorndal, J G Boissevain, H Borel, K Boyle, M L Brooks, D S Brown, D Bucher, H Buesching, V Bumazhnov, G Bunce, J M Burward-Hoy, S Butsyk, S Campbell, J-S Chai, B S Chang, J-L Charvet, S Chernichenko, J Chiba, C Y Chi, M Chiu, I J Choi, T Chujo, P Chung, A Churyn, V Cianciolo, C R Cleven, Y Cobigo, B A Cole, M P Comets, P Constantin, M Csanád, T Csörgo, T Dahms, K Das, G David, M B Deaton, K Dehmelt, H Delagrange, A Denisov, D d'Enterria, A Deshpande, E J Desmond, O Dietzsch, A Dion, M Donadelli, J L Drachenberg, O Drapier, A Drees, A K Dubey, A Durum, V Dzhordzhadze, Y V Efremenko, J Egdemir, F Ellinghaus, W S Emam, A Enokizono, H En'yo, B Espagnon, S Esumi, K O Eyser, D E Fields, M Finger, M Finger Jr, F Fleuret, S L Fokin, B Forestier, Z Fraenkel, J E Frantz, A Franz, A D Frawley, K Fujiwara, Y Fukao, S-Y Fung, T Fusayasu, S Gadrat, I Garishvili, F Gastineau, M Germain, A Glenn, H Gong, M Gonin, J Gosset, Y Goto, R Granier de Cassagnac, N Grau, S V Greene, M Grosse Perdekamp, T Gunji, H-A Gustafsson, T Hachiya, A Hadj Henni, C Haegemann, J S Haggerty, M N Hagiwara, H Hamagaki, R Han, H Harada, E P Hartouni, K Haruna, M Harvey, E Haslum, K Hasuko, R Hayano, M Heffner, T K Hemmick, T Hester, J M Heuser, X He, H Hiejima, J C Hill, R Hobbs, M Hohlmann, M Holmes, W Holzmann, K Homma, B Hong, T Horaguchi, D Hornback, M G Hur, T Ichihara, K Imai, M Inaba, Y Inoue, D Isenhower, L Isenhower, M Ishihara, T Isobe, M Issah, A Isupov, B V Jacak, J Jia, J Jin, O Jinnouchi, B M Johnson, K S Joo, D Jouan, F Kajihara, S Kametani, N Kamihara, J Kamin, M Kaneta, J H Kang, H Kanou, T Kawagishi, D Kawall, A V Kazantsev, S Kelly, A Khanzadeev, J Kikuchi, D H Kim, D J Kim, E Kim, Y-S Kim, E Kinney, A Kiss, E Kistenev, A Kiyomichi, J Klay, C Klein-Boesing, L Kochenda, V Kochetkov, B Komkov, M Konno, D Kotchetkov, A Kozlov, A Král, A Kravitz, P J Kroon, J Kubart, G J Kunde, N Kurihara, K Kurita, M J Kweon, Y Kwon, G S Kyle, R Lacey, Y-S Lai, J G Lajoie, A Lebedev, Y Le Bornec, S Leckey, D M Lee, M K Lee, T Lee, M J Leitch, M A L Leite, B Lenzi, H Lim, T Liska, A Litvinenko, M X Liu, X Li, X H Li, B Love, D Lynch, C F Maguire, Y I Makdisi, A Malakhov, M D Malik, V I Manko, Y Mao, L Masek, H Masui, F Matathias, M C McCain, M McCumber, P L McGaughey, Y Miake, P Mikes, K Miki, T E Miller, A Milov, S Mioduszewski, G C Mishra, M Mishra, J T Mitchell, M Mitrovski, A Morreale, D P Morrison, J M Moss, T V Moukhanova, D Mukhopadhyay, J Murata, S Nagamiya, Y Nagata, J L Nagle, M Naglis, I Nakagawa, Y Nakamiya, T Nakamura, K Nakano, J Newby, M Nguyen, B E Norman, A S Nyanin, J Nystrand, E O'Brien, S X Oda, C A Ogilvie, H Ohnishi, I D Ojha, H Okada, K Okada, M Oka, O O Omiwade, A Oskarsson, I Otterlund, M Ouchida, K Ozawa, R Pak, D Pal, A P T Palounek, V Pantuev, V Papavassiliou, J Park, W J Park, S F Pate, H Pei, J-C Peng, H Pereira, V Peresedov, D Yu Peressounko, C Pinkenburg, R P Pisani, M L Purschke, A K Purwar, H Qu, J Rak, A Rakotozafindrabe, I Ravinovich, K F Read, S Rembeczki, M Reuter, K Reygers, V Riabov, Y Riabov, G Roche, A Romana, M Rosati, S S E Rosendahl, P Rosnet, P Rukoyatkin, V L Rykov, S S Ryu, B Sahlmueller, N Saito, T Sakaguchi, S Sakai, H Sakata, V Samsonov, H D Sato, S Sato, S Sawada, J Seele, R Seidl, V Semenov, R Seto, D Sharma, T K Shea, I Shein, A Shevel, T-A Shibata, K Shigaki, M Shimomura, T Shohjoh, K Shoji, A Sickles, C L Silva, D Silvermyr, C Silvestre, K S Sim, C P Singh, V Singh, S Skutnik, M Slunecka, W C Smith, A Soldatov, R A Soltz, W E Sondheim, S P Sorensen, I V Sourikova, F Staley, P W Stankus, E Stenlund, M Stepanov, A Ster, S P Stoll, T Sugitate, C Suire, J P Sullivan, J Sziklai, T Tabaru, S Takagi, E M Takagui, A Taketani, K H Tanaka, Y Tanaka, K Tanida, M J Tannenbaum, A Taranenko, P Tarján, T L Thomas, M Togawa, A Toia, J Tojo, L Tomásek, H Torii, R S Towell, V-N Tram, I Tserruya, Y Tsuchimoto, S K Tuli, H Tydesjö, N Tyurin, C Vale, H Valle, H W van Hecke, J Velkovska, R Vertesi, A A Vinogradov, M Virius, V Vrba, E Vznuzdaev, M Wagner, D Walker, X R Wang, Y Watanabe, J Wessels, S N White, N Willis, D Winter, C L Woody, M Wysocki, W Xie, Y L Yamaguchi, A Yanovich, Z Yasin, J Ying, S Yokkaichi, G R Young, I Younus, I E Yushmanov, W A Zajc, O Zaudtke, C Zhang, S Zhou, J Zimányi, L Zolin; PHENIX Collaboration

Affiliation

¹ University of Colorado, Boulder, Colorado 80309, USA.

PMID: 20481877
DOI: 10.1103/PhysRevLett.104.132301

Abstract

The production of e+ e- pairs for m(e+ e-)<0.3 GeV/c2 and 1<p(T)<5 GeV/c is measured in p+p and Au+Au collisions at square root(S(NN))=200 GeV. An enhanced yield above hadronic sources is observed. Treating the excess as photon internal conversions, the invariant yield of direct photons is deduced. In central Au+Au collisions, the excess of the direct photon yield over p+p is exponential in transverse momentum, with an inverse slope T=221+/-19(stat)+/-19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T(init) approximately 300-600 MeV at times of approximately 0.6-0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition to quark gluon plasma at approximately 170 MeV.