1. Disentangling Centrality Bias and Final-State Effects in the Production of High-p_{T} Neutral Pions Using Direct Photon in d+Au Collisions at sqrt[s_{NN}]=200 GeV.
- Author
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Abdulameer NJ, Acharya U, Aidala C, Akiba Y, Alfred M, Aoki K, Apadula N, Ayuso C, Babintsev V, Barish KN, Bathe S, Bazilevsky A, Belmont R, Berdnikov A, Berdnikov Y, Bichon L, Blankenship B, Blau DS, Boer M, Bok JS, Borisov V, Brooks ML, Bryslawskyj J, Bumazhnov V, Butler C, Campbell S, Canoa Roman V, Chiu M, Connors M, Corliss R, Corrales Morales Y, Csanád M, Csörgő T, Liu LD, Danley TW, Daugherity MS, David G, Dean CT, DeBlasio K, Dehmelt K, Denisov A, Deshpande A, Desmond EJ, Doomra V, Do JH, Drees A, Drees KA, Dumancic M, Durham JM, Durum A, Elder T, Enokizono A, Esha R, Fadem B, Fan W, Feege N, Finger M, Finger M, Firak D, Fitzgerald D, Fokin SL, Frantz JE, Franz A, Frawley AD, Fukuda Y, Gal C, Garg P, Ge H, Giles M, Goto Y, Grau N, Greene SV, Gunji T, Hachiya T, Haggerty JS, Hahn KI, Han SY, Harvey M, Hasegawa S, Haseler TOS, Hemmick TK, He X, Hill K, Hodges A, Homma K, Hong B, Hoshino T, Hotvedt N, Huang J, Imrek J, Inaba M, Isenhower D, Ito Y, Ivanishchev D, Jacak BV, Ji Z, Johnson BM, Jorjadze V, Jouan D, Jumper DS, Kang JH, Kapukchyan D, Karthas S, Kazantsev AV, Khachatryan V, Khanzadeev A, Khatiwada A, Kim C, Kim DJ, Kim EJ, Kim M, Kim MH, Kim T, Kincses D, Kingan A, Kistenev E, Koblesky T, Kotov D, Kovacs L, Kudo S, Kurgyis B, Kurita K, Lajoie JG, Lallow EO, Larionova D, Lebedev A, Lee SH, Leitch MJ, Leung YH, Lewis NA, Lim SH, Liu MX, Li X, Loggins VR, Loomis DA, Lynch D, Lökös S, Majoros T, Makek M, Malaev M, Manko VI, Mannel E, Masuda H, McCumber M, McGlinchey D, Mignerey AC, Mihalik DE, Milov A, Mishra DK, Mitchell JT, Mitrankova M, Mitrankov I, Mitsuka G, Mondal MM, Moon T, Morrison DP, Morrow SI, Muhammad A, Mulilo B, Murakami T, Murata J, Nagai K, Nagashima K, Nagashima T, Nagle JL, Nagy MI, Nakagawa I, Nakagomi H, Nakano K, Nattrass C, Nelson S, Nouicer R, Novitzky N, Novotny R, Novák T, Nukazuka G, Nyanin AS, O'Brien E, Ogilvie CA, Oh J, Orjuela Koop JD, Orosz M, Osborn JD, Oskarsson A, Ozawa K, Pantuev V, Papavassiliou V, Park JS, Park S, Patel M, Pate SF, Peng W, Perepelitsa DV, Perera GDN, PerezLara CE, Petti R, Phipps M, Pinkenburg C, Potekhin M, Pun A, Purschke ML, Radzevich PV, Ramasubramanian N, Read KF, Riabov V, Riabov Y, Richford D, Rinn T, Rosati M, Rowan Z, Runchey J, Sakaguchi T, Sako H, Samsonov V, Sarsour M, Sato K, Sato S, Schaefer B, Schmoll BK, Seidl R, Sen A, Seto R, Sexton A, Sharma D, Shein I, Shibata M, Shibata TA, Shigaki K, Shimomura M, Shi Z, Silva CL, Silvermyr D, Slunečka M, Smith KL, Sorensen SP, Sourikova IV, Stankus PW, Stoll SP, Sugitate T, Sukhanov A, Sun Z, Syed S, Takahama R, Takeda A, Tanida K, Tannenbaum MJ, Tarafdar S, Taranenko A, Tarnai G, Tieulent R, Timilsina A, Todoroki T, Tomášek M, Towell CL, Towell RS, Tserruya I, Ueda Y, Ujvari B, van Hecke HW, Vazquez-Carson S, Velkovska J, Virius M, Vrba V, Wang XR, Wang Z, Watanabe Y, Wong CP, Xu C, Xu Q, Yamaguchi YL, Yanovich A, Yin P, Yoon I, Yoo JH, Yushmanov IE, Yu H, Zajc WA, and Zou L
- Abstract
PHENIX presents a simultaneous measurement of the production of direct γ and π^{0} in d+Au collisions at sqrt[s_{NN}]=200 GeV over a p_{T} range of 7.5 to 18 GeV/c for different event samples selected by event activity, i.e., charged-particle multiplicity detected at forward rapidity. Direct-photon yields are used to empirically estimate the contribution of hard-scattering processes in the different event samples. Using this estimate, the average nuclear-modification factor, R_{dAu,EXP}^{π^{0}}, is 0.925±0.023(stat)±0.15(scale), consistent with unity for minimum-bias (MB) d+Au collisions. For event classes with low and moderate event activity, R_{dAu,EXP}^{π^{0}} is consistent with the MB value within 5% uncertainty. This result confirms that the previously observed enhancement of high-p_{T} π^{0} production found in small-system collisions with low event activity is a result of a bias in interpreting event activity within the Glauber framework. In contrast, for the top 5% of events with the highest event activity, R_{dAu,EXP}^{π^{0}} is suppressed by 20% relative to the MB value with a significance of 4.5σ, which may be due to final-state effects. This suppression corresponds to a p_{T} shift of δp_{T}=0.213±0.055 Gev/c at 9 Gev/c.
- Published
- 2025
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