Measurement of jet quenching in O+O collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV by the STAR experiment at RHIC

Abstract

The STAR experiment at the Relativistic Heavy Ion Collider presents measurements of correlations between charged hadron triggers of high transverse momenta ($7<p_{\mathrm{T}}<30$ GeV/$c$) with recoiling charged hadrons ($3<p_{\mathrm{T}}<7$ GeV/$c$) or charged--particle jets ($p_{\mathrm{T},\mathrm{jet}}>8$ GeV/$c$) in event--activity selected O+O collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV. Yields of associated hadrons and jets, normalized by the number of trigger hadrons, are suppressed by approximately 20\% in high event activity relative to low event activity collisions, with an absence of suppression excluded with high significance. This suppression corresponds to a shift in p_{\rm T} of $0.70\pm 0.15(stat.)\pm 0.10(syst.)$ GeV/$c$ for large--radius charged--particle jets ($R=0.5$), quantifying their energy redistribution due to final--state interactions. These measurements provide strong evidence for jet quenching in O+O collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV, offering new insight into quark--gluon plasma formation in small collision systems.