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

TL;DR

This paper reports the first evidence of jet quenching in oxygen-oxygen collisions at RHIC, showing a 20% suppression in associated hadron and jet yields, indicating quark-gluon plasma formation in small systems.

Contribution

It provides the first measurement of jet quenching effects in O+O collisions at RHIC energies, revealing energy redistribution due to final-state interactions.

Findings

Associated hadron and jet yields are suppressed by about 20% in high activity events.

A shift of 0.70 GeV/c in jet transverse momentum is observed, indicating energy redistribution.

Strong evidence for jet quenching in small collision systems at RHIC.

Abstract

The STAR experiment at the Relativistic Heavy Ion Collider presents measurements of correlations between charged hadron triggers of high transverse momenta ($7 < p_{\rm T} < 30$ GeV/$c$) with recoiling charged hadrons ($3 < p_{\rm T} < 7$ GeV/$c$) or charged--particle jets ($p_{\rm T, jet} > 8$ 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 $0.70\pm0.15~(\rm stat.)~\pm0.10~(\rm syst.)$ 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.