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

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.