Measurement of Jet Quenching in O+O Collisions at s NN = 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 < pT < 30 GeV/c) with recoiling charged hadrons (3 < pT < 7 GeV/c) or charged--particle jets (pT, jet > 8 GeV/c) in event--activity selected O+O collisions at √sNN=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 pT of 0.70±0.15~( stat.)~±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 √sNN=200 GeV, offering new insight into quark--gluon plasma formation in small collision systems.