Suppression of Υ{hooked} production in d + Au and Au + Au collisions at sNN=200GeV

Author(s): Adamczyk, L; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Alekseev, I; Alford, J; Anson, CD; Aparin, A; Arkhipkin, D; Aschenauer, EC; Averichev, GS; Balewski, J; Banerjee, A; Barnovska, Z; Beavis, DR; Bellwied, R; Bhasin, A; Bhati, AK; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Borowski, W; Bouchet, J; Brandin, AV; Brovko, SG; Bultmann, S; Bunzarov, I; Burton, TP; Butterworth, J; Caines, H; Calderon de la Barca Sanchez, M; Cebra, D; Cendejas, R; Cervantes, MC; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, HF; Chen, JH; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, MJM; Corliss, R; Cramer, JG; Crawford, HJ; Cui, X; Das, S; Davila Leyva, A; De Silva, LC; Debbe, RR; Dedovich, TG; Deng, J; Derevschikov, AA; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, JL; Draper, JE; Du, CM; Dunkelberger, LE; Dunlop, JC; Efimov, LG; Engelage, J; Engle, KS; Eppley, G; Eun, L; Evdokimov, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E | Abstract: We report measurements of Υ{hooked} meson production in p + p, d + Au, and Au + Au collisions using the STAR detector at RHIC. We compare the Υ{hooked} 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 Υ{hooked}(1S + 2S + 3S) in the rapidity range |y| l 1 in d + Au collisions ofR dAu= 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + psyst.). 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 ofR A A= 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 Υ{hooked} 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. © 2014.