Suppression of Upsilon production in d plus Au and Au plus Au collisions at root S-NN=200 GeV

0433026 - ÚJF 2015 RIV NL eng J - Journal Article
Adamczyk, L. - Adkins, J. K. - Agakishiev, G. - Aggarwal, M. M. - Ahammed, Z. - Alekseev, I. - Alford, J. - Anson, C. - Aparin, A. A. - Arkhipkin, D. - Aschenauer, E. - Averichev, G. S. - Barnovská, Zuzana - Bielčík, J. - Bielčíková, Jana - Chaloupka, P. - Hajková, O. - Pachr, M. - Rusňák, Jan - Šumbera, Michal - Vértési, Robert … Total 360 authors
Suppression of Upsilon production in d plus Au and Au plus Au collisions at root S-NN=200 GeV.
Physics Letters. B. Roč. 735, JUL (2014), s. 127-137. ISSN 0370-2693. E-ISSN 1873-2445
R&D Projects: GA MŠMT LA09013
Institutional support: RVO:61389005
Keywords : STAR * RHIC * heavy ion collisions
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Impact factor: 6.131, year: 2014

We report measurements of Upsilon meson production in p + p, d + Au, and Au + Au collisions using the STAR detector at RHIC. We compare the Upsilon yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au + Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range vertical bar y vertical bar < 1 in d + Au collisions of R-dAu = 0.79 +/- 0.24(stat.) +/- 0.03(syst.) +/- 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R-AA = 0.49 +/- 0.1(stat.) +/- 0.02(syst.) +/- 0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark-Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.
Permanent Link: http://hdl.handle.net/11104/0237349