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Measurement of Direct Photons in Au plus Au Collisions at root s(NN)=200 GeV

Afanasiev, S. ; Aidala, C. ; Ajitanand, N. N. ; Akiba, Y. ; Al-Jamel, A. ; Alexander, J. ; Aoki, K. ; Aphecetche, L. ; Armendariz, R. and Aronson, S. H. , et al. (2012) In Physical Review Letters 109(15).
Abstract
We report the measurement of direct photons at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c < pT < 22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R-AA was calculated as a function of p(T) for different Au + Au collision centralities using the measured p + p direct photon spectrum and compared to theoretical predictions. R-AA was found to be consistent with unity for all centralities over the entire measured pT range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution... (More)
We report the measurement of direct photons at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c < pT < 22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R-AA was calculated as a function of p(T) for different Au + Au collision centralities using the measured p + p direct photon spectrum and compared to theoretical predictions. R-AA was found to be consistent with unity for all centralities over the entire measured pT range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R-AA from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Letters
volume
109
issue
15
article number
152302
publisher
American Physical Society
external identifiers
  • wos:000309590300014
  • scopus:84867370476
ISSN
1079-7114
DOI
10.1103/PhysRevLett.109.152302
language
English
LU publication?
yes
id
1ebbead6-7795-4663-8796-c8a7df616868 (old id 3174574)
date added to LUP
2016-04-01 09:52:29
date last changed
2023-04-03 00:58:43
@article{1ebbead6-7795-4663-8796-c8a7df616868,
  abstract     = {{We report the measurement of direct photons at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c &lt; pT &lt; 22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R-AA was calculated as a function of p(T) for different Au + Au collision centralities using the measured p + p direct photon spectrum and compared to theoretical predictions. R-AA was found to be consistent with unity for all centralities over the entire measured pT range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R-AA from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.}},
  author       = {{Afanasiev, S. and Aidala, C. and Ajitanand, N. N. and Akiba, Y. and Al-Jamel, A. and Alexander, J. and Aoki, K. and Aphecetche, L. and Armendariz, R. and Aronson, S. H. and Averbeck, R. and Awes, T. C. and Azmoun, B. and Babintsev, V. and Baldisseri, A. and Barish, K. N. and Barnes, P. D. and Bassalleck, B. and Bathe, S. and Batsouli, S. and Baublis, V. and Bauer, F. and Bazilevsky, A. and Belikov, S. and Bennett, R. and Berdnikov, Y. and Bjorndal, M. T. and Boissevain, J. G. and Borel, H. and Boyle, K. and Brooks, M. L. and Brown, D. S. and Bucher, D. and Buesching, H. and Bumazhnov, V. and Bunce, G. and Burward-Hoy, J. M. and Butsyk, S. and Campbell, S. and Chai, J. -S. and Chernichenko, S. and Chi, C. Y. and Chiba, J. and Chiu, M. and Choi, I. J. and Chujo, T. and Cianciolo, V. and Cleven, C. R. and Cobigo, Y. and Cole, B. A. and Comets, M. P. and Connors, M. and Constantin, P. and Csanad, M. and Csoergo, T. and Dahms, T. and Das, K. and David, G. and Delagrange, H. and Denisov, A. and d'Enterria, D. and Deshpande, A. and Desmond, E. J. and Dietzsch, O. and Dion, A. and Drachenberg, J. L. and Drapier, O. and Drees, A. and Dubey, A. K. and Durum, A. and Dzhordzhadze, V. and Efremenko, Y. V. and Egdemir, J. and Enokizono, A. and En'yo, H. and Espagnon, B. and Esumi, S. and Fields, D. E. and Fleuret, F. and Fokin, S. L. and Forestier, B. and Fraenkel, Z. and Frantz, J. E. and Franz, A. and Frawley, A. D. and Fukao, Y. and Fung, S. -Y. and Gadrat, S. and Gastineau, F. and Germain, M. and Glenn, A. and Gonin, M. and Gosset, J. and Goto, Y. and de Cassagnac, R. Granier and Grau, N. and Greene, S. V. and Perdekamp, M. Grosse and Gunji, T. and Gustafsson, Hans-Åke and Hachiya, T. and Henni, A. Hadj and Haggerty, J. S. and Hagiwara, M. N. and Hamagaki, H. and Harada, H. and Hartouni, E. P. and Haruna, K. and Harvey, M. and Haslum, Eva and Hasuko, K. and Hayano, R. and He, X. and Heffner, M. and Hemmick, T. K. and Heuser, J. M. and Hiejima, H. and Hill, J. C. and Hobbs, R. and Holmes, M. and Holzmann, W. and Homma, K. and Hong, B. and Horaguchi, T. and Hur, M. G. and Ichihara, T. and Iinuma, H. and Imai, K. and Imrek, J. and Inaba, M. and Isenhower, D. and Isenhower, L. and Ishihara, M. and Isobe, T. and Issah, M. and Isupov, A. and Jacak, B. V. and Jia, J. and Jin, J. and Jinnouchi, O. and Johnson, B. M. and Joo, K. S. and Jouan, D. and Kajihara, F. and Kametani, S. and Kamihara, N. and Kaneta, M. and Kang, J. H. and Kawagishi, T. and Kazantsev, A. V. and Kelly, S. and Khanzadeev, A. and Kim, D. J. and Kim, E. and Kim, Y. -S. and Kinney, E. and Kiss, A. and Kistenev, E. and Kiyomichi, A. and Klein-Boesing, C. and Kochenda, L. and Kochetkov, V. and Komkov, B. and Konno, M. and Kotchetkov, D. and Kozlov, A. and Kroon, P. J. and Kunde, G. J. and Kurihara, N. and Kurita, K. and Kweon, M. J. and Kwon, Y. and Kyle, G. S. and Lacey, R. and Lajoie, J. G. and Lebedev, A. and Le Bornec, Y. and Leckey, S. and Lee, D. M. and Lee, M. K. and Leitch, M. J. and Leite, M. A. L. and Li, X. H. and Lim, H. and Litvinenko, A. and Liu, M. X. and Maguire, C. F. and Makdisi, Y. I. and Malakhov, A. and Malik, M. D. and Manko, V. I. and Masui, H. and Matathias, F. and McCain, M. C. and McGaughey, P. L. and Miake, Y. and Miller, T. E. and Milov, A. and Mioduszewski, S. and Mishra, G. C. and Mitchell, J. T. and Morrison, D. P. and Moss, J. M. and Moukhanova, T. V. and Mukhopadhyay, D. and Murata, J. and Nagamiya, S. and Nagata, Y. and Nagle, J. L. and Naglis, M. and Nakamura, T. and Newby, J. and Nguyen, M. and Norman, B. E. and Nyanin, A. S. and Nystrand, Joakim and O'Brien, E. and Ogilvie, C. A. and Ohnishi, H. and Ojha, I. D. and Okada, K. and Omiwade, O. O. and Oskarsson, Anders and Otterlund, Ingvar and Ozawa, K. and Pak, R. and Pal, D. and Palounek, A. P. T. and Pantuev, V. and Papavassiliou, V. and Park, J. and Park, W. J. and Pate, S. F. and Pei, H. and Peng, J. -C. and Pereira, H. and Peresedov, V. and Peressounko, D. Yu. and Pinkenburg, C. and Pisani, R. P. and Purschke, M. L. and Purwar, A. K. and Qu, H. and Rak, J. and Ravinovich, I. and Read, K. F. and Reuter, M. and Reygers, K. and Riabov, V. and Riabov, Y. and Roche, G. and Romana, A. and Rosati, M. and Rosendahl, Sarah and Rosnet, P. and Rukoyatkin, P. and Rykov, V. L. and Ryu, S. S. and Sahlmueller, B. and Saito, N. and Sakaguchi, T. and Sakai, S. and Samsonov, V. and Sato, H. D. and Sato, S. and Sawada, S. and Semenov, V. and Seto, R. and Sharma, D. and Shea, T. K. and Shein, I. and Shibata, T. -A. and Shigaki, K. and Shimomura, M. and Shohjoh, T. and Shoji, K. and Sickles, A. and Silva, C. L. and Silvermyr, D. and Sim, K. S. and Singh, C. P. and Singh, V. and Skutnik, S. and Smith, W. C. and Soldatov, A. and Soltz, R. A. and Sondheim, W. E. and Sorensen, S. P. and Sourikova, I. V. and Staley, F. and Stankus, P. W. and Stenlund, Evert and Stepanov, M. and Ster, A. and Stoll, S. P. and Sugitate, T. and Suire, C. and Sullivan, J. P. and Sziklai, J. and Tabaru, T. and Takagi, S. and Takagui, E. M. and Taketani, A. and Tanaka, K. H. and Tanaka, Y. and Tanida, K. and Tannenbaum, M. J. and Taranenko, A. and Tarjan, P. and Thomas, T. L. and Togawa, M. and Tojo, J. and Torii, H. and Towell, R. S. and Tram, V-N. and Tserruya, I. and Tsuchimoto, Y. and Tuli, S. K. and Tydesjö, Henrik and Tyurin, N. and Vale, C. and Valle, H. and van Hecke, H. W. and Velkovska, J. and Vertesi, R. and Vinogradov, A. A. and Vznuzdaev, E. and Wagner, M. and Wang, X. R. and Watanabe, Y. and Wessels, J. and White, S. N. and Willis, N. and Winter, D. and Woody, C. L. and Wysocki, M. and Xie, W. and Yanovich, A. and Yokkaichi, S. and Young, G. R. and Younus, I. and Yushmanov, I. E. and Zajc, W. A. and Zaudtke, O. and Zhang, C. and Zimanyi, J. and Zolin, L.}},
  issn         = {{1079-7114}},
  language     = {{eng}},
  number       = {{15}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Letters}},
  title        = {{Measurement of Direct Photons in Au plus Au Collisions at root s(NN)=200 GeV}},
  url          = {{http://dx.doi.org/10.1103/PhysRevLett.109.152302}},
  doi          = {{10.1103/PhysRevLett.109.152302}},
  volume       = {{109}},
  year         = {{2012}},
}