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Detailed measurement of the e(+)e(-) pair continuum in p plus p and Au plus Au collisions at root s(NN)=200 GeV and implications for direct photon production

Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Alexander, J.; Al-Jamel, A.; Aoki, K. and Aphecetche, L., et al. (2010) In Physical Review C (Nuclear Physics) 81(3).
Abstract
PHENIX has measured the e(+)e(-) pair continuum in root s(NN) = 200 GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e(+)e(-) yield is compared to the expectations from hadronic sources, based on PHENIX measurements. In the intermediate-mass region, between the masses of the phi and the J/psi meson, the yield is consistent with expectations from correlated c (c) over bar production, although other mechanisms are not ruled out. In the low-mass region, below the phi, the p+p inclusive mass spectrum is well described by known contributions from light meson decays. In contrast, the Au+Au minimum bias inclusive mass spectrum in this region shows an enhancement by a factor of 4.7 +/- 0.4(stat) +/- 1.5(syst) +/-... (More)
PHENIX has measured the e(+)e(-) pair continuum in root s(NN) = 200 GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e(+)e(-) yield is compared to the expectations from hadronic sources, based on PHENIX measurements. In the intermediate-mass region, between the masses of the phi and the J/psi meson, the yield is consistent with expectations from correlated c (c) over bar production, although other mechanisms are not ruled out. In the low-mass region, below the phi, the p+p inclusive mass spectrum is well described by known contributions from light meson decays. In contrast, the Au+Au minimum bias inclusive mass spectrum in this region shows an enhancement by a factor of 4.7 +/- 0.4(stat) +/- 1.5(syst) +/- 0.9(model). At low mass (m(ee) < 0.3 GeV/c(2)) and high p(T) (1 < p(T) < 5 GeV/c) an enhanced e(+)e(-) pair yield is observed that is consistent with production of virtual direct photons. This excess is used to infer the yield of real direct photons. In central Au+Au collisions, the excess of the direct photon yield over the p+p is exponential in p(T), with inverse slope T = 221 +/- 19(stat) +/- 19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T-init similar or equal to 300-600 MeV at times of 0.6-0.15 fm/c after the collision are in qualitative agreement with the direct photon data in Au+Au. For low p(T) < 1 GeV/c the low-mass region shows a further significant enhancement that increases with centrality and has an inverse slope of T similar or equal to 100 MeV. Theoretical models underpredict the low-mass, low-p(T) enhancement. (Less)
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Physical Review C (Nuclear Physics)
volume
81
issue
3
publisher
American Physical Society
external identifiers
  • wos:000276769400063
  • scopus:77950936872
ISSN
0556-2813
DOI
10.1103/PhysRevC.81.034911
language
English
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yes
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0f082ee8-16d3-4f41-94b4-610c1cabade2 (old id 1602117)
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2010-05-19 10:42:35
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@article{0f082ee8-16d3-4f41-94b4-610c1cabade2,
  abstract     = {PHENIX has measured the e(+)e(-) pair continuum in root s(NN) = 200 GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e(+)e(-) yield is compared to the expectations from hadronic sources, based on PHENIX measurements. In the intermediate-mass region, between the masses of the phi and the J/psi meson, the yield is consistent with expectations from correlated c (c) over bar production, although other mechanisms are not ruled out. In the low-mass region, below the phi, the p+p inclusive mass spectrum is well described by known contributions from light meson decays. In contrast, the Au+Au minimum bias inclusive mass spectrum in this region shows an enhancement by a factor of 4.7 +/- 0.4(stat) +/- 1.5(syst) +/- 0.9(model). At low mass (m(ee) &lt; 0.3 GeV/c(2)) and high p(T) (1 &lt; p(T) &lt; 5 GeV/c) an enhanced e(+)e(-) pair yield is observed that is consistent with production of virtual direct photons. This excess is used to infer the yield of real direct photons. In central Au+Au collisions, the excess of the direct photon yield over the p+p is exponential in p(T), with inverse slope T = 221 +/- 19(stat) +/- 19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T-init similar or equal to 300-600 MeV at times of 0.6-0.15 fm/c after the collision are in qualitative agreement with the direct photon data in Au+Au. For low p(T) &lt; 1 GeV/c the low-mass region shows a further significant enhancement that increases with centrality and has an inverse slope of T similar or equal to 100 MeV. Theoretical models underpredict the low-mass, low-p(T) enhancement.},
  articleno    = {034911},
  author       = {Adare, A. and Afanasiev, S. and Aidala, C. and Ajitanand, N. N. and Akiba, Y. and Al-Bataineh, H. and Alexander, J. and Al-Jamel, A. and Aoki, K. and Aphecetche, L. and Armendariz, R. and Aronson, S. H. and Asai, J. and Atomssa, E. T. and Averbeck, R. and Awes, T. C. and Azmoun, B. and Babintsev, V. and Baksay, G. and Baksay, L. 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 Bickley, A. A. 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 Chang, B. S. and Charvet, J-L. and Chernichenko, S. and Chiba, J. and Chi, C. Y. and Chiu, M. and Choi, I. J. and Chujo, T. and Chung, P. and Churyn, A. and Cianciolo, V. and Cleven, C. R. and Cobigo, Y. and Cole, B. A. and Comets, M. P. and Constantin, P. and Csanad, M. and Csorgo, T. and Dahms, T. and Das, K. and David, G. and Deaton, M. B. and Dehmelt, K. and Delagrange, H. and Denisov, A. and d'Enterria, D. and Deshpande, A. and Desmond, E. J. and Dietzsch, O. and Dion, A. and Donadelli, M. 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 Ellinghaus, F. and Emam, W. S. and Enokizono, A. and En'yo, H. and Espagnon, B. and Esumi, S. and Eyser, K. O. and Fields, D. E. and Finger, M., Jr. and Finger, M. 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 Fujiwara, K. and Fukao, Y. and Fung, S-Y. and Fusayasu, T. and Gadrat, S. and Garishvili, I. and Gastineau, F. and Germain, M. and Glenn, A. and Gong, H. 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 Haegemann, C. and Haggerty, J. S. and Hagiwara, M. N. and Hamagaki, H. and Han, R. and Harada, H. and Hartouni, E. P. and Haruna, K. and Harvey, M. and Haslum, Eva and Hasuko, K. and Hayano, R. and Heffner, M. and Hemmick, T. K. and Hester, T. and Heuser, J. M. and He, X. and Hiejima, H. and Hill, J. C. and Hobbs, R. and Hohlmann, M. and Holmes, M. and Holzmann, W. and Homma, K. and Hong, B. and Horaguchi, T. and Hornback, D. and Hur, M. G. and Ichihara, T. and Imai, K. and Inaba, M. and Inoue, Y. 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 Kamin, J. and Kaneta, M. and Kang, J. H. and Kanou, H. and Kawagishi, T. and Kawall, D. and Kazantsev, A. V. and Kelly, S. and Khanzadeev, A. and Kikuchi, J. and Kim, D. H. and Kim, D. J. and Kim, E. and Kim, Y-S. and Kinney, E. and Kiss, A. and Kistenev, E. and Kiyomichi, A. and Klay, J. and Klein-Boesing, C. and Kochenda, L. and Kochetkov, V. and Komkov, B. and Konno, M. and Kotchetkov, D. and Kozlov, A. and Kral, A. and Kravitz, A. and Kroon, P. J. and Kubart, 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 Lai, Y-S. and Lajoie, J. G. and Lebedev, A. and Le Bornec, Y. and Leckey, S. and Lee, D. M. and Lee, M. K. and Lee, T. and Leitch, M. J. and Leite, M. A. L. and Lenzi, B. and Lim, H. and Liska, T. and Litvinenko, A. and Liu, M. X. and Li, X. and Li, X. H. and Love, B. and Lynch, D. and Maguire, C. F. and Makdisi, Y. I. and Malakhov, A. and Malik, M. D. and Manko, V. I. and Mao, Y. and Masek, L. and Masui, H. and Matathias, F. and McCain, M. C. and McCumber, M. and McGaughey, P. L. and Miake, Y. and Mikes, P. and Miki, K. and Miller, T. E. and Milov, A. and Mioduszewski, S. and Mishra, G. C. and Mishra, M. and Mitchell, J. T. and Mitrovski, M. and Morreale, A. 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 Nakagawa, I. and Nakamiya, Y. and Nakamura, T. and Nakano, K. and Newby, J. and Nguyen, M. and Norman, B. E. and Nouicer, R. and Nyanin, A. S. and Nystrand, Joakim and O'Brien, E. and Oda, S. X. and Ogilvie, C. A. and Ohnishi, H. and Ojha, I. D. and Okada, H. and Okada, K. and Oka, M. and Omiwade, O. O. and Oskarsson, Anders and Otterlund, Ingvar and Ouchida, M. 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 Rakotozafindrabe, A. and Ravinovich, I. and Read, K. F. and Rembeczki, S. 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 Sakata, H. and Samsonov, V. and Sato, H. D. and Sato, S. and Sawada, S. and Seele, J. and Seidl, R. and Semenov, V. and Seto, R. and Sharma, D. and Shea, T. K. and Shein, I. and Shevel, A. 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 Silvestre, C. and Sim, K. S. and Singh, C. P. and Singh, V. and Skutnik, S. and Slunecka, M. 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 Toia, A. and Tojo, J. and Tomasek, L. 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 Virius, M. and Vrba, V. and Vznuzdaev, E. and Wagner, M. and Walker, D. 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 Yamaguchi, Y. L. and Yanovich, A. and Yasin, Z. and Ying, J. 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 Zhou, S. and Zimanyi, J. and Zolin, L.},
  issn         = {0556-2813},
  language     = {eng},
  number       = {3},
  publisher    = {American Physical Society},
  series       = {Physical Review C (Nuclear Physics)},
  title        = {Detailed measurement of the e(+)e(-) pair continuum in p plus p and Au plus Au collisions at root s(NN)=200 GeV and implications for direct photon production},
  url          = {http://dx.doi.org/10.1103/PhysRevC.81.034911},
  volume       = {81},
  year         = {2010},
}