Azimuthal anisotropy of direct photons in collisions at
N. J. Abdulameer15,22, U. Acharya19, A. Adare12, C. Aidala42, N. N. Ajitanand60,*, Y. Akiba55,56,†, M. Alfred21, S. Antsupov58, N. Apadula27,61 et al. (PHENIX Collaboration)
N. Apadula27,61, H. Asano34,55, B. Azmoun7, V. Babintsev23, M. Bai6, N. S. Bandara40, B. Bannier61, E. Bannikov58, K. N. Barish8, S. Bathe5,56, A. Bazilevsky7, M. Beaumier8, S. Beckman12, R. Belmont12,49, A. Berdnikov58, Y. Berdnikov58, L. Bichon66, B. Blankenship66, D. S. Blau33,46, J. S. Bok48, V. Borisov58, K. Boyle56, M. L. Brooks36, J. Bryslawskyj5,8, V. Bumazhnov23, S. Campbell13,27, C.-H. Chen56, D. Chen61, M. Chiu7, C. Y. Chi13, I. J. Choi24, J. B. Choi29,*, T. Chujo64, Z. Citron67, M. Connors19,56, R. Corliss61, M. Csanád16, T. Csörgő41,68, T. W. Danley50, A. Datta47, M. S. Daugherity1, G. David7,61, K. DeBlasio47, K. Dehmelt61, A. Denisov23, A. Deshpande56,61, E. J. Desmond7, A. Dion61, P. B. Diss39, V. Doomra61, J. H. Do69, A. Drees61, K. A. Drees6, J. M. Durham36, A. Durum23, A. Enokizono55,57, R. Esha61, B. Fadem44, W. Fan61, N. Feege61, D. E. Fields47, M. Finger, Jr.9, M. Finger9, D. Firak15,61, D. Fitzgerald42, S. L. Fokin33, J. E. Frantz50, A. Franz7, A. D. Frawley18, P. Gallus14, C. Gal61, P. Garg3,61, H. Ge61, M. Giles61, F. Giordano24, A. Glenn35, Y. Goto55,56, N. Grau2, S. V. Greene66, M. Grosse Perdekamp24, T. Gunji11, T. Guo61, T. Hachiya55,56, J. S. Haggerty7, K. I. Hahn17, H. Hamagaki11, H. F. Hamilton1, J. Hanks61, S. Y. Han17,32, S. Hasegawa28, T. O. S. Haseler19, K. Hashimoto55,57, T. K. Hemmick61, X. He19, J. C. Hill27, A. Hodges19,24, R. S. Hollis8, K. Homma20, B. Hong32, T. Hoshino20, N. Hotvedt27, J. Huang7, K. Imai28, M. Inaba64, A. Iordanova8, D. Isenhower1, D. Ivanishchev54, B. V. Jacak61, M. Jezghani19, X. Jiang36, Z. Ji61, B. M. Johnson7,19, D. Jouan52, D. S. Jumper24, S. Kanda11, J. H. Kang69, G. Kasza41,68, D. Kawall40, A. V. Kazantsev33, J. A. Key47, V. Khachatryan61, A. Khanzadeev54, B. Kimelman44, C. Kim32, D. J. Kim30, E.-J. Kim29, G. W. Kim17, M. Kim59, E. Kistenev7, R. Kitamura11, J. Klatsky18, D. Kleinjan8, P. Kline61, T. Koblesky12, B. Komkov54, D. Kotov54,58, L. Kovacs16, K. Kurita57, M. Kurosawa55,56, Y. Kwon69, J. G. Lajoie27,51, D. Larionova58, A. Lebedev27, S. Lee69, S. H. Lee27,61, M. J. Leitch36, S. H. Lim69, M. X. Liu36, X. Li10, X. Li36, D. A. Loomis42, D. Lynch7, S. Lökös68, Y. I. Makdisi6, M. Makek70, A. Manion61, V. I. Manko33, E. Mannel7, M. McCumber36, P. L. McGaughey36, D. McGlinchey12,36, C. McKinney24, A. Meles48, M. Mendoza8, A. C. Mignerey39, A. Milov67, D. K. Mishra4, J. T. Mitchell7, M. Mitrankova58,61, Iu. Mitrankov58,61, S. Miyasaka55,63, S. Mizuno55,64, A. K. Mohanty4, P. Montuenga24, T. Moon32,69, D. P. Morrison7, T. V. Moukhanova33, B. Mulilo32,55,71, T. Murakami34,55, J. Murata55,57, A. Mwai60, K. Nagashima20, J. L. Nagle12, M. I. Nagy16, I. Nakagawa55,56, H. Nakagomi55,64, K. Nakano55,63, C. Nattrass62, P. K. Netrakanti4, T. Niida64, S. Nishimura11, R. Nouicer7,56, N. Novitzky30,61, T. Novák41,68, G. Nukazuka55,56, A. S. Nyanin33, E. O'Brien7, C. A. Ogilvie27, J. D. Orjuela Koop12, M. Orosz15,22, J. D. Osborn42,51, A. Oskarsson37, K. Ozawa31,64, R. Pak7, V. Pantuev25, V. Papavassiliou48, J. S. Park59, S. Park43,55,59,61, M. Patel27, S. F. Pate48, J.-C. Peng24, D. V. Perepelitsa7,12, G. D. N. Perera48, D.Yu. Peressounko33, J. Perry27, R. Petti7,61, C. Pinkenburg7, R. Pinson1, R. P. Pisani7, M. Potekhin7, M. L. Purschke7, J. Rak30, B. J. Ramson42, I. Ravinovich67, K. F. Read51,62, D. Reynolds60, V. Riabov46,54, Y. Riabov54,58, D. Richford5,65, T. Rinn27, S. D. Rolnick8, M. Rosati27, Z. Rowan5, J. G. Rubin42, B. Sahlmueller61, N. Saito31, T. Sakaguchi7, H. Sako28, V. Samsonov46,54, M. Sarsour19, S. Sato28, B. Schaefer66, B. K. Schmoll62, K. Sedgwick8, R. Seidl55,56, A. Seleznev58, A. Sen27,62, R. Seto8, P. Sett4, A. Sexton39, D. Sharma61, I. Shein23, T.-A. Shibata55,63, K. Shigaki20, M. Shimomura27,45, P. Shukla4, A. Sickles7,24, C. L. Silva36, D. Silvermyr37,51, B. K. Singh3, C. P. Singh3,*, V. Singh3, M. Slunečka9, K. L. Smith18,36, M. Snowball36, R. A. Soltz35, W. E. Sondheim36, S. P. Sorensen62, I. V. Sourikova7, P. W. Stankus51, M. Stepanov40,*, S. P. Stoll7, T. Sugitate20, A. Sukhanov7, T. Sumita55, J. Sun61, Z. Sun15,22,61, J. Sziklai68, A. Taketani55,56, K. Tanida28,56,59, M. J. Tannenbaum7, S. Tarafdar66,67, A. Taranenko46,60, R. Tieulent19,38, A. Timilsina27, T. Todoroki55,56,64, M. Tomášek14, C. L. Towell1, R. Towell1, R. S. Towell1, I. Tserruya67, B. Ujvari15,22, H. W. van Hecke36, J. Velkovska66, M. Virius14, V. Vrba14,26, X. R. Wang48,56, Z. Wang5, Y. Watanabe55,56, Y. S. Watanabe11,31, F. Wei48, A. S. White42, C. L. Woody7, M. Wysocki51, B. Xia50, L. Xue19, S. Yalcin61, Y. L. Yamaguchi11,61, A. Yanovich23, I. Yoon59, J. H. Yoo32, I. E. Yushmanov33, H. Yu48,53, W. A. Zajc13, A. Zelenski6, S. Zhou10, and L. Zou8 (PHENIX Collaboration)
- 1Abilene Christian University, Abilene, Texas 79699, USA
- 2Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
- 3Department of Physics, Banaras Hindu University, Varanasi 221005, India
- 4Bhabha Atomic Research Centre, Bombay 400 085, India
- 5Baruch College, City University of New York, New York, New York, 10010 USA
- 6Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
- 7Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
- 8University of California-Riverside, Riverside, California 92521, USA
- 9Charles University, Faculty of Mathematics and Physics, 180 00 Troja, Prague, Czech Republic
- 10Science and Technology on Nuclear Data Laboratory, China Institute of Atomic Energy, Beijing 102413, People's Republic of China
- 11Center for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
- 12University of Colorado, Boulder, Colorado 80309, USA
- 13Columbia University, New York, New York 10027 and Nevis Laboratories, Irvington, New York 10533, USA
- 14Czech Technical University, Zikova 4, 166 36 Prague 6, Czech Republic
- 15Debrecen University, H-4010 Debrecen, Egyetem tér 1, Hungary
- 16ELTE, Eötvös Loránd University, H-1117 Budapest, Pázmány P. s. 1/A, Hungary
- 17Ewha Womans University, Seoul 120-750, Korea
- 18Florida State University, Tallahassee, Florida 32306, USA
- 19Georgia State University, Atlanta, Georgia 30303, USA
- 20Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- 21Department of Physics and Astronomy, Howard University, Washington, DC 20059, USA
- 22HUN-REN ATOMKI, H-4026 Debrecen, Bem tér 18/c, Hungary
- 23IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, Russia
- 24University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- 25Institute for Nuclear Research of the Russian Academy of Sciences, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, Russia
- 26Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech Republic
- 27Iowa State University, Ames, Iowa 50011, USA
- 28Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan
- 29Jeonbuk National University, Jeonju, 54896, Korea
- 30Helsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI-40014 Jyväskylä, Finland
- 31KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
- 32Korea University, Seoul 02841, Korea
- 33National Research Center “Kurchatov Institute”, Moscow, 123098 Russia
- 34Kyoto University, Kyoto 606-8502, Japan
- 35Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- 36Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- 37Department of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden
- 38IPNL, CNRS/IN2P3, Univ Lyon, Université Lyon 1, F-69622, Villeurbanne, France
- 39University of Maryland, College Park, Maryland 20742, USA
- 40Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337, USA
- 41MATE, Institute of Technology, Laboratory of Femtoscopy, Károly Róbert Campus, H-3200 Gyöngyös, Mátrai út 36, Hungary
- 42Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
- 43Mississippi State University, Mississippi State, Mississippi 39762, USA
- 44Muhlenberg College, Allentown, Pennsylvania 18104-5586, USA
- 45Nara Women's University, Kita-uoya Nishi-machi Nara 630-8506, Japan
- 46National Research Nuclear University, MEPhI, Moscow Engineering Physics Institute, Moscow, 115409, Russia
- 47University of New Mexico, Albuquerque, New Mexico 87131, USA
- 48New Mexico State University, Las Cruces, New Mexico 88003, USA
- 49Physics and Astronomy Department, University of North Carolina at Greensboro, Greensboro, North Carolina 27412, USA
- 50Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
- 51Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- 52IPN-Orsay, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, BP1, F-91406, Orsay, France
- 53Peking University, Beijing 100871, People's Republic of China
- 54PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region 188300, Russia
- 55RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan
- 56RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
- 57Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan
- 58Saint Petersburg State Polytechnic University, St. Petersburg 195251, Russia
- 59Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea
- 60Chemistry Department, Stony Brook University, SUNY, Stony Brook, New York 11794-3400, USA
- 61Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, New York 11794-3800, USA
- 62University of Tennessee, Knoxville, Tennessee 37996, USA
- 63Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan
- 64Tomonaga Center for the History of the Universe, University of Tsukuba, Tsukuba, Ibaraki 305, Japan
- 65United States Merchant Marine Academy, Kings Point, New York 11024, USA
- 66Vanderbilt University, Nashville, Tennessee 37235, USA
- 67Weizmann Institute, Rehovot 76100, Israel
- 68Institute for Particle and Nuclear Physics, HUN-REN Wigner Research Centre for Physics, (HUN-REN Wigner RCP, RMI), H-1525 Budapest 114, POBox 49, Budapest, Hungary
- 69Yonsei University, IPAP, Seoul 120-749, Korea
- 70Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32 HR-10002 Zagreb, Croatia
- 71Department of Physics, School of Natural Sciences, University of Zambia, Great East Road Campus, Box 32379, Lusaka, Zambia
- *Deceased.
- †PHENIX Spokesperson: akiba@rcf.rhic.bnl.gov
Phys. Rev. C 114, 024903 – Published 7 August, 2026
DOI: https://doi.org/10.1103/21nh-lrvx
Abstract
The PHENIX experiment at the Relativistic Heavy Ion Collider measured the second Fourier component of the direct-photon azimuthal anisotropy at midrapidity in collisions at . The results are presented in 10% wide bins of collision centrality and cover the transverse-momentum range of , and are in quantitative agreement with findings published earlier, but provide better granularity and higher reach. Above a of , where hard scattering dominates the direct-photon production, is consistent with zero. At lower , direct photon as a function of is comparable to the anisotropy over all centralities, albeit being overall slightly smaller. The results are compared to recent theory calculations that include, in addition to thermal radiation from the quark-gluon plasma and hadron gas, sources of photons from preequilibrium, strong magnetic fields, or radiative hadronization. While the newer theoretical calculations describe the data better than previous models, none of them alone can fully explain the results.