Observation of Excess J/ψ Yield at Very Low Transverse Momenta in Au+Au Collisions at $$\sqrt{s_{NN}} =$$ 200 GeV and U+U Collisions at $$\sqrt{s_{NN}} =$$ 193 GeV

Journal Article · 27 September 2019 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.123.132302 · OSTI ID:1566931

Adam, J.; Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Atetalla, F.; Attri, A.; Averichev, G. S.; Bairathi, V.; Barish, K.; Bassill, A. J. ; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Brandenburg, J. D.; Brandin, A. V.; Bryslawskyj, J.; Bunzarov, I.; Butterworth, J.; Caines, H.; Sánchez, M. Calderón de la Barca; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chan, B. K.; Chang, F-H.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Crawford, H. J.; Csanad, M.; Das, S.; Dedovich, T. G.; Deppner, I. M.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Dunlop, J. C.; Edmonds, T.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Y.; Filip, P.; Finch, E.; Fisyak, Y.; Fulek, L.; Gagliardi, C. A.; Galatyuk, T.; Geurts, F.; Gibson, A.; Grosnick, D.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Herrmann, N.; Holub, L.; Hong, Y.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, S. L.; Huang, T.; Huang, X.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Ju, X.; Judd, E. G.; Kabana, S.; Kagamaster, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kelsey, M.; Kikoła, D. P.; Kim, C.; Kinghorn, T. A.; Kisel, I.; Kisiel, A.; Kocan, M.; Kochenda, L.; Kosarzewski, L. K.; Kramarik, L.; Kravtsov, P.; Krueger, K.; Mudiyanselage, N. Kulathunga; Kumar, L.; Elayavalli, R. Kunnawalkam; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, C.; Li, W.; Li, W.; Li, X.; Li, Y.; Liang, Y.; Licenik, R.; Lin, T.; Lipiec, A.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, P.; Liu, P.; Liu, X.; Liu, Y.; Liu, Z.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, R.; Ma, Y. G.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Matonoha, O.; Mazer, J. A.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Mooney, I.; Moravcova, Z.; Morozov, D. A.; Nasim, Md.; Nayak, K.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Odyniec, G.; Ogawa, A.; Oh, K.; Oh, S.; Okorokov, V. A.; Page, B. S.; Pak, R.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pinter, R. L.; Pluta, J.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Quintero, A.; Radhakrishnan, S. K.; Ramachandran, S.; Ray, R. L.; Reed, R.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Schambach, J.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seck, F.; Seger, J.; Sergeeva, M.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Shen, F.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Siejka, S.; Sikora, R.; Simko, M.; JSingh,; Singha, S.; Smirnov, D.; Smirnov, N.; Solyst, W.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, X. M.; Sun, Y.; Sun, Y.; Surrow, B.; Svirida, D. N.; Szymanski, P.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Todoroki, T.; Tokarev, M.; Tomkiel, C. A.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Tu, B.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; Vanek, J.; Vasiliev, A. N.; Vassiliev, I.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Wang, F.; Wang, G.; Wang, P.; Wang, Y.; Wang, Y.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, H.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, C.; Yang, Q.; Yang, S.; Yang, Y.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I. -K.; Zbroszczyk, H.; Zha, W. ; Zhang, D.; Zhang, L.; Zhang, S.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z.; Zhao, J.; Zhong, C.; Zhou, C.; Zhu, X.; Zhu, Z.; Zurek, M. K.; Zyzak, M.

We report on the first measurements of J/ψ production at very low transverse momentum ($$p_T <$$ 0.2 GeV/c) in hadronic Au + Au collisions at $$\sqrt{s_{NN}} =$$ 200 GeV and U + U collisions at $$\sqrt{s_{NN}} =$$ 193 GeV. Remarkably, the inferred nuclear modification factor of J/ψ at midrapidity in Au + Au (U + U) collisions reaches about 24 (52) for $$p_T <$$ 0.05 GeV/c in the 60%–80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the dN/dt distribution of J/ψ for the very low $$p_T$$ range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of J/ψ yield observed at extremely low $$p_T$$ originates from coherent photon-nucleus interactions. In particular, coherently produced J/ψ’s in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.

• Research Organization: Texas A & M Univ., College Station, TX (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF); Ministry of Education and Science of the Russian Federation; National Natural Science Foundation of China (NSFC); Chinese Academy of Sciences (CAS); Ministry of Science and Technology of the People’s Republic of China; Ministry of Education of China; National Research Foundation of Korea (NRF); Czech Science Foundation (GACR); Ministry of Education, Youth and Sports of the Czech Republic; Hungarian National Research, Development and Innovation Office (NRDI); Hungarian Ministry of Human Capacities; Government of India; National Science Centre of Poland (NCN); Ministry of Science, Education and Sports of the Republic of Croatia; ROSATOM of Russia; German Federal Ministry of Education and Research (BMBF)
• Contributing Organization: STAR Collaboration
• Grant/Contract Number: SC0017982; AC02-05CH11231; SC0015636; SC0012704
• OSTI ID: 1566931
• Alternate ID(s): OSTI ID: 1523247; OSTI ID: 1594832; OSTI ID: 1616089; OSTI ID: 1787584
• Report Number(s): BNL-211606-2019-JAAM; PRLTAO; TRN: US2101583
• Journal Information: Physical Review Letters, Vol. 123, Issue 13; ISSN 0031-9007
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English