Speaker
Description
Jet-quenching, the suppression of high-$p_{\mathrm{T}}$ partons traversing the hot and dense QCD medium, is a key signature of quark-gluon plasma (QGP) formation in heavy-ion collisions. Whether an analogous effect persists in small collision systems at LHC and whether it is dense and extended enough to modify hard probes, remains an open and interesting question. The recent LHC oxygen-oxygen (OO) run bridges the gap between pp and large systems such as Pb-Pb. It provides a system with a small but non-negligible path length, in which jet-medium effects, if present, may become visible. Di-hadron azimuthal correlations at high-$p_{\mathrm{T}}$ are sensitive to parton energy loss and a model-based study of these correlations in OO and pp is therefore a timely input for understanding the onset of jet-quenching and for guiding the experimental analyses.
In this work, we present a study of jet-quenching effects in OO and pp collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV using A Multi-Phase Transport (AMPT) model with string melting. The high-$p_{\mathrm{T}}$ di-hadron azimuthal correlations are studied using trigger hadrons in the range 8 < $p_{\mathrm{T,trig}}$ < 16 GeV/c and associated hadrons in the range 0.15 < $p_{\mathrm{T,assoc}}$ < 8 GeV/c, at midrapidity. The near-side (NS) and away-side (AS) per-trigger yields are extracted and the medium-induced modifications are quantified by comparing the OO results with the pp baseline through the ratio of per-trigger yields ($I_{\mathrm{OO}}$). The AMPT models parton energy loss through partonic scatterings in the parton cascade stage, therefore the results show how much of the away-side suppression in small systems can be attributed to partonic interactions and path-length effects. They also provide model predictions for comparison with experimental measurements in OO collisions at the LHC.