Correlations of event activity with hard and soft processes in $p$ + Au collisions at $\sqrt{s_\mathrm{NN}}$ = 200 GeV at STAR

• Main Authors: STAR Collaboration, Abdulhamid, M. I, Adam, J, Aschenauer, E. C, Bairathi, V, Barish, K, Bhasin, A, Bhosale, S. R, Broodo, C, Chaloupka, P, Chan, B. K, Chen, J, Chen, Z, Deppner, I. M, Eppley, G, Feng, Y, Finch, E, Fu, C, Geurts, F, Ghimire, N, Gupta, A, Guryn, W, Harabasz, S, Harris, J. W, He, W, Isshiki, M, Jalotra, A, Khanal, A, Kikoła, D. P, Kincses, D, Knospe, A. G, Kosarzewski, L. K, Labonte, M. C, Landgraf, J. M, Li, D, Li, W, Liang, X, Liu, G, Liu, L, Liu, Z, Lu, T, Luo, J, Luo, X. F, Ma, Y. G, Markert, C, McNamara, G, Mioduszewski, S, Mondal, B, Nelson, J. M, Nie, M, Nigmatkulov, G, Niida, T, Ogawa, A, Pal, S, Pandav, A, Paul, A, Perkins, C, Reed, R, Roy, D, Chowdhury, P. Roy, Ruan, L, Sahoo, A. K, Schaefer, B. C, Schmidke, W. B, Seger, J, Seto, R, Shah, N, Sharma, M, Sharma, N, Sheikh, A. I, Shen, D. Y, Shen, K, Shi, S. S, Si, F, Srivastava, B, Stewart, D. J, Sun, C, Svoboda, M, Tamis, A. C, Thomas, J. H, Tribedy, P, Tsang, C. Y, Tyler, J, Vanek, J, Wang, G, Wang, J, Wang, X, Wielanek, D, Wu, J, Xie, W, Xu, Q. H, Yang, S, Yang, Y, Zha, W, Zhang, C, Zhang, W, Zhang, X, Zhang, Z. J, Zhao, F, Zhao, J
• Format: Journal Article
• Language: English
• Published: 12-04-2024
• Subjects: Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.2404.08784

Phys. Rev. C 110, 044908 Published 16 October 2024 With the STAR experiment at the BNL Relativisic Heavy Ion Collider, we
characterize $\sqrt{s_\mathrm{NN}}$ = 200 GeV p+Au collisions by event activity
(EA) measured within the pseudorapidity range $eta$ $in$ [-5, -3.4] in the
Au-going direction and report correlations between this EA and hard- and soft-
scale particle production at midrapidity ($\eta$ $\in$ [-1, 1]). At the soft
scale, charged particle production in low-EA p+Au collisions is comparable to
that in p+p collisions and increases monotonically with increasing EA. At the
hard scale, we report measurements of high transverse momentum (pT) jets in
events of different EAs. In contrast with the soft particle production, high-pT
particle production and EA are found to be inversely related. To investigate
whether this is a signal of jet quenching in high-EA events, we also report
ratios of pT imbalance and azimuthal separation of dijets in high- and low-EA
events. Within our measurement precision, no significant differences are
observed, disfavoring the presence of jet quenching in the highest 30% EA p+Au
collisions at $\sqrt{s_\mathrm{NN}}$ = 200 GeV.