| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1851134 | Physics Letters B | 2014 | 11 Pages |
We report measurements of ϒ meson production in p+pp+p, d+Aud+Au, and Au+AuAu+Au collisions using the STAR detector at RHIC. We compare the ϒ yield to the measured cross section in p+pp+p collisions in order to quantify any modifications of the yield in cold nuclear matter using d+Aud+Au data and in hot nuclear matter using Au+AuAu+Au data separated into three centrality classes. Our p+pp+p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for ϒ(1S+2S+3S)ϒ(1S+2S+3S) in the rapidity range |y|<1|y|<1 in d+Aud+Au collisions of RdAu=0.79±0.24(stat.)±0.03(syst.)±0.10(p+p syst.)RdAu=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+AuAu+Au collisions, we measure a nuclear modification factor of RAA=0.49±0.1(stat.)±0.02(syst.)±0.06(p+psyst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state ϒ mesons in Au+AuAu+Au collisions. The additional suppression in Au+AuAu+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+Aud+Au is still needed before any definitive statements about the nature of the suppression in Au+AuAu+Au can be made.
