Nuclear modification factors of phi mesons in d plus Au, Cu plus Cu, and Au plus Au collisions at root s(NN)=200 GeV

Date
2011-02-18
Authors
Adare, Andrew
Belikov, Sergey
Ogilvie, Craig
Constantin, Paul
Dion, Alan
Grau, Nathan
Hill, John
Kempel, Todd
Lajoie, John
Lebedev, Alexandre
Ogilvie, Craig
Pei, H.
Rak, Jan
Rosati, Marzia
Silva, C.
Skutnik, S.
Vale, Carla
Wei, Feng
et al.
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Abstract

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed systematic measurements of phi meson production in the K+K- decay channel at midrapidity in p + p, d + Au, Cu + Cu, and Au + Au collisions at root s(NN) = 200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R-AA for Au + Au and Cu + Cu, and R-dA for d + Au collisions, studied as a function of transverse momentum (1 < p(T) < 7 GeV/c) and centrality. In central and midcentral Au + Au collisions, the R-AA of phi exhibits a suppression relative to expectations from binary scaled p + p results. The amount of suppression is smaller than that of the pi(0) and the. in the intermediate p(T) range (2-5 GeV/c), whereas, at higher p(T), the phi, pi(0), and. show similar suppression. The baryon (proton and antiproton) excess observed in central Au + Au collisions at intermediate p(T) is not observed for the phi meson despite the similar masses of the proton and the phi. This suggests that the excess is linked to the number of valence quarks in the hadron rather than its mass. The difference gradually disappears with decreasing centrality, and, for peripheral collisions, the R-AA values for both particle species are consistent with binary scaling. Cu + Cu collisions show the same yield and suppression as Au + Au collisions for the same number of N-part. The R-dA of phi shows no evidence for cold nuclear effects within uncertainties.

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This article is published as Adare, A., S. Afanasiev, C. Aidala, N. N. Ajitanand, Y. Akiba, H. Al-Bataineh, J. Alexander et al. "Nuclear modification factors of ϕ mesons in d+ Au, Cu+ Cu, and Au+ Au collisions at s NN= 200 GeV." Physical Review C 83, no. 2 (2011): 024909. DOI:10.1103/PhysRevC.83.024909. Posted with permission.

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