Observation of the Electromagnetic Field Effect via Charge-Dependent Directed Flow in Heavy-Ion Collisions at the Relativistic Heavy Ion Collider

Journal Article · 22 February 2024 · Physical Review. X

DOI: https://doi.org/10.1103/PhysRevX.14.011028 · OSTI ID:2311230

Abdulhamid, M. I.; Aboona, B. E.; Adam, J.; Adams, J. R.; Agakishiev, G.; Aggarwal, I.; Aggarwal, M. M.; Ahammed, Z.; Aitbaev, A.; Alekseev, I.; Alpatov, E.; Aparin, A.; Aslam, S.; Atchison, J.; Averichev, G. S.; Bairathi, V.; Ball Cap, J. G.; Barish, K.; Bhagat, P.; Bhasin, A. ; Bhatta, S.; Bhosale, S. R.; Bordyuzhin, I. G.; Brandenburg, J. D.; Brandin, A. V.; Cai, X. Z.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Ceska, J.; Chakaberia, I.; Chan, B. K.; Chang, Z.; Chatterjee, A.; Chen, D.; Chen, J.; Chen, J. H. ; Chen, Z.; Cheng, J.; Cheng, Y.; Choudhury, S.; Christie, W.; Chu, X.; Crawford, H. J.; Dale-Gau, G.; Das, A.; Dash, A. P.; Daugherity, M.; Dedovich, T. G.; Deppner, I. M.; Derevschikov, A. A.; Dhamija, A.; Dixit, P.; Dong, X.; Drachenberg, J. L.; Duckworth, E.; Dunlop, J. C.; Engelage, J.; Eppley, G.; Esumi, S.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Feng, C. J.; Feng, Y.; Finch, E.; Fisyak, Y.; Flor, F. A.; Fu, C.; Gao, T.; Geurts, F.; Ghimire, N.; Gibson, A.; Gopal, K.; Gou, X.; Grosnick, D.; Gupta, A.; Hamed, A.; Han, Y.; Harasty, M. D.; Harris, J. W.; Harrison-Smith, H.; He, W.; He, X. H.; He, Y.; Hu, C.; Hu, Q.; Hu, Y.; Huang, H.; Huang, H. Z.; Huang, S. L.; Huang, T.; Huang, X.; Huang, Y.; Huang, Y.; Humanic, T. J.; Isenhower, D.; Isshiki, M.; Jacobs, W. W.; Jalotra, A.; Jena, C.; Ji, Y.; Jia, J.; Jin, C.; Ju, X.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Keane, D.; Kechechyan, A.; Kiselev, A.; Knospe, A. G.; Ko, H. S.; Kochenda, L.; Korobitsin, A. A.; Kraeva, A. Yu.; Kravtsov, P.; Kumar, L.; Labonte, M. C.; Lacey, R.; Landgraf, J. M.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Leung, Y. H.; Lewis, N.; Li, C.; Li, H-S.; Li, W.; Li, X.; Li, Y.; Li, Y.; Li, Z.; Liang, X.; Liang, Y.; Lin, T.; Lin, Y.; Liu, C.; Liu, F.; Liu, G.; Liu, H.; Liu, L.; Liu, T.; Liu, X.; Liu, Y.; Liu, Z.; Ljubicic, T.; Lomicky, O.; Longacre, R. S.; Loyd, E. M.; Lu, T.; Lukow, N. S.; Luo, X. F.; Luong, V. B.; Ma, L.; Ma, R.; Ma, Y. G.; Magdy, N.; Mallick, D.; Margetis, S.; Matis, H. S.; McNamara, G.; Mi, K.; Minaev, N. G.; Mohanty, B.; Mondal, M. M.; Mooney, I.; Morozov, D. A.; Mudrokh, A.; Nagy, M. I.; Nain, A. S.; Nam, J. D.; Nasim, M.; Nedorezov, E.; Neff, D.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Odyniec, G.; Ogawa, A.; Oh, S.; Okorokov, V. A.; Okubo, K.; Page, B. S.; Pak, R.; Pandav, A.; Panebratsev, Y.; Pani, T.; Parfenov, P.; Paul, A.; Perkins, C.; Pokhrel, B. R.; Posik, M.; Povarov, A.; Protzman, T.; Pruthi, N. K.; Putschke, J.; Qin, Z.; Qiu, H.; Quintero, A.; Racz, C.; Radhakrishnan, S. K.; Rana, A.; Ray, R. L.; Ritter, H. G.; Robertson, C. W.; Rogachevsky, O. V.; Rosales Aguilar, M. A.; Roy, D.; Ruan, L.; Sahoo, A. K.; Sahoo, N. R.; Sako, H.; Salur, S.; Samigullin, E.; Sato, S.; Schaefer, B. C.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, T.; Sharma, M.; Sharma, N.; Sharma, R.; Sharma, S. R.; Sheikh, A. I.; Shen, D.; Shen, D. Y.; Shen, K.; Shi, S. S.; Shi, Y.; Shou, Q. Y.; Si, F.; Singh, J.; Singha, S.; Sinha, P.; Skoby, M. J.; Söhngen, Y.; Song, Y.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Su, Y.; Sun, C.; Sun, X.; Sun, Y.; Sun, Y.; Surrow, B.; Svirida, D. N.; Sweger, Z. W.; Tamis, A. C.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Thomas, J. H.; Tlusty, D.; Todoroki, T.; Tokarev, M. V.; Trentalange, S.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Tsang, C. Y.; Tu, Z.; Tyler, J.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; Vasiliev, A. N.; Verkest, V.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Wang, F.; Wang, G. ; Wang, J. S.; Wang, J.; Wang, X.; Wang, Y.; Wang, Y.; Wang, Y.; Wang, Z.; Webb, J. C.; Weidenkaff, P. C.; Westfall, G. D.; Wieman, H.; Wilks, G.; Wissink, S. W.; Wu, J.; Wu, J.; Wu, X.; Wu, X.; Xi, B.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, H.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Y.; Xu, Z.; Xu, Z.; Yan, G.; Yan, Z.; Yang, C.; Yang, Q.; Yang, S.; Yang, Y.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yu, Y.; Zha, W.; Zhang, C.; Zhang, D.; Zhang, J.; Zhang, S.; Zhang, W.; Zhang, X.; Zhang, Y.; Zhang, Y.; Zhang, Y.; Zhang, Y.; Zhang, Z. J.; Zhang, Z.; Zhang, Z.; Zhao, F.; Zhao, J.; Zhao, M.; Zhou, C.; Zhou, J.; Zhou, S.; Zhou, Y.; Zhu, X.; Zurek, M.; Zyzak, M.

The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of the fundamental properties of matter under extreme conditions. Noncentral collisions can produce strong magnetic fields on the order of ${10}^{18}\mathrm{G}$ , which offers a probe into the electrical conductivity of the QGP. In particular, quarks and antiquarks carry opposite charges and receive contrary electromagnetic forces that alter their momenta. This phenomenon can be manifested in the collective motion of final-state particles, specifically in the rapidity-odd directed flow, denoted as $v_1\left(\mathsf{y}\right)$ . Here, we present the charge-dependent measurements of $d{v}_1/d\mathsf{y}$ near midrapidities for ${\pi }^{\pm }$ , $K^{\pm }$ , and $p\left(\overline{p}\right)$ in $\mathrm{Au}+\mathrm{Au}$ and isobar ( ${}_{44}{}^{96}\mathrm{Ru}+{}_{44}{}^{96}\mathrm{Ru}$ and ${}_{40}{}^{96}\mathrm{Zr}+{}_{40}{}^{96}\mathrm{Zr}$ ) collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ , and in $\mathrm{Au}+\mathrm{Au}$ collisions at 27 GeV, recorded by the STAR detector at the Relativistic Heavy Ion Collider. The combined dependence of the $v_1$ signal on collision system, particle species, and collision centrality can be qualitatively and semiquantitatively understood as several effects on constituent quarks. While the results in central events can be explained by the $u$ and $d$ quarks transported from initial-state nuclei, those in peripheral events reveal the impacts of the electromagnetic field on the QGP. Our data put valuable constraints on the electrical conductivity of the QGP in theoretical calculations. Published by the American Physical Society 2024

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: Bundesministerium für Bildung und Forschung (BMBF); Croatian Ministry of Science, Education and Sports; Czech Science Foundation (GA CR); Government of India; Japan Society for the Promotion of Science (JSPS); Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan; National Natural Science Foundation of China; National Research Foundation (NRF) of Korea; National Science Centre (Poland) (NSC); National Science Foundation (NSF); USDOE Office of Science (SC), Nuclear Physics (NP)
• Contributing Organization: Lawrence Berkeley National Laboratory (LBNL); STAR Collaboration
• Grant/Contract Number: AC02-06CH11357; SC0012704
• OSTI ID: 2311230
• Report Number(s): BNL-224223-2023-JAAM; 011028
• Journal Information: Physical Review. X, Journal Name: Physical Review. X Journal Issue: 1 Vol. 14; ISSN PRXHAE; ISSN 2160-3308
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English