Studies of jet quenching in O+O collisions at √s_NN = 200 GeV by STAR

Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, China

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Published online: 17 April 2026

Abstract

Jet quenching is a well-established probe of the QGP in large collision systems such as Au+Au and Pb+Pb, but is not observed 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_AA and R_CP at high transverse momentum (p_T), inclusive jet R_CP, and semi-inclusive hadron+jet I_CP, using O+O collisions data collected with the STAR detector in 2021 at √s_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_CP and h+jet I_CP are found to be below unity, indicating suppression relative to peripheral events.