Suraj Prasad, Neelkamal Mallick (2026.07.01 - 10.30)

Abstract: Heavy-ion collisions are primarily studied to investigate the properties of hot and dense primordial nuclear matter, known as the quark–gluon plasma (QGP). However, recent observations of hydrodynamic flow–like behavior in pp and p–Pb collisions at the LHC suggest the possible formation of QGP droplets even in the smallest collision systems. To bridge the multiplicity gap between small and large systems and to examine the applicability of hydrodynamic descriptions, OO and Ne–Ne collisions have been studied for the first time at the LHC. This work focuses mainly on the study of dihadron correlation measurements in pO, OO, and Ne–Ne collisions. Dihadron correlations measure particle yield in relative pseudorapidity (\(\Delta \eta\)) and relative azimuthal angle (\(\Delta \varphi\)) for a pair of triggers and associated particles. For high-\(p_{T}\) triggers, the correlation on the near-side (NS), \(\Delta \varphi \approx 0\), is dominated by jet fragmentation pairs, while on the away-side (AS), \(\Delta \varphi \approx \pi\), the correlation mostly comes from the sub-leading jet. Therefore, the yield and shape of the correlation function measured at NS and AS are sensitive to the presence of a medium. In fact, in heavy-ion collisions, the multiplicity and \(p_T\) -dependent modifications of the dihadron correlation function is generally attributed to the medium effect.

In this ongoing work, the width and yield of the NS and AS jet-like correlation are studied as a function of charged-particle multiplicity at midrapidity. Further, the pertrigger normalized relative yield of NS and AS correlations (\(I_{AA}\) and \(I_{CP}\) ) are being measured in pO, OO, and Ne–Ne collisions for the first time. For the interpretation of the physics message, model-to-data comparisons are the needed. Specifically, the results are being compared with predictions from several model calculations, including PYTHIA, AMPT, JEWEL, and JETSCAPE. These results will help quantify possible jet-medium interactions in small and light-ion collision systems.