Studies of jet quenching in O+O collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV by STAR

TL;DR

This study investigates jet quenching phenomena in O+O collisions at 200 GeV, providing new insights into how jet suppression varies with system size in quark-gluon plasma conditions.

Contribution

It presents the first measurements of jet quenching observables in O+O collisions, bridging the understanding between small and large collision systems.

Findings

Inclusive charged hadron $R_{AA}$ and $R_{CP}$ are below unity, indicating suppression.

Inclusive jet $R_{CP}$ shows suppression in central collisions.

Semi-inclusive hadron+jet $I_{CP}$ also indicates jet quenching effects.

Abstract

Jet quenching is a well-established probe of the QGP in large collision systems such as Au+Au and Pb+Pb, but is absent in smaller p+A collisions despite the presence of collectivity. This makes it important to study its dependence on system size. O+O collisions offer an ideal opportunity, bridging the gap between small and large systems. In these proceedings, we present the measurements of the following observables related to jet quenching: inclusive charged hadron $R_{\rm AA}$ and $R_{\rm CP}$ at high transverse momentum ($p_{\rm T}$), inclusive jet $R_{\rm CP}$, and semi-inclusive hadron+jet $I_{\rm CP}$, using O+O collisions data collected with the STAR detector in 2021 at $\sqrt{s_{\rm NN}} = 200$ GeV. For jet measurements, combinatorial background is subtracted based on the event mixing technique, while background fluctuations and detector effects are corrected via unfolding. Inclusive charged hadron and jet $R_{\rm CP}$ and h+jet $I_{\rm CP}$ are found to be below unity, indicating suppression relative to peripheral events.