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

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 ($p_{\mathrm{T},\mathrm{j}\mathrm{e}\mathrm{t}}>8$ GeV/$c$) in event–activity selected O+O collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=200$ 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 $0.70\pm 0.15(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{.})\pm 0.10(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{.})$ 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 $\sqrt{s_{\mathrm{N}\mathrm{N}}}=200$ GeV, offering new insight into quark–gluon plasma formation in small collision systems.