Event activity correlations and jet measurements in p+Au collisions at \(\sqrt{s_\mathrm{NN}}\) = 200 GeV

Abstract

With the STAR experiment at RHIC, 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 mid-rapidity (\(\eta\in[-1,1]\)). At the soft scale, charged particle production in low-EA \(p\)+Au collisions is comparable to that in \pp collisions and increases monotonically with increasing EA. At the hard scale, we report measurements of high transverse momentum (\(p_\mathrm{T}\)) jets in events of different EAs. In contrast to the soft particle production, high-\(p_\mathrm{T}\) 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 \(p_\mathrm{T}\) 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.