Speaker
Description
In relativistic heavy-ion collisions, a hot and dense QCD medium, known as the Quark-Gluon Plasma, is formed. Simultaneously, hard-scattered partons from these collisions interact with the medium, leading to the production of particle cascades called jets. These jets are modified as they traverse the QGP, a phenomenon referred to as jet quenching. Various jet observables, including jet mass ($M_{\text{jet}}$), have been studied to explore this modification process.
For jets with low transverse momenta ($p_{\text{T,jet}}$), distinguishing jets originating from hard scattering remains a significant challenge due to the large contributions from combinatorial background in heavy-ion collisions. To address this issue, methods for measuring recoil jets with respect to high-$p_{\text{T}}$ trigger particles ($9\leq p_{\text{T,trigger}} <30$) in a semi-inclusive manner have been developed. In particular, the STAR Collaboration has employed a mixed-event technique in combination with semi-inclusive recoil jet measurements to provide a data-driven method for correction of uncorrelated background effects. In this study, we extend the method of semi-inclusive recoil jet measurement to the measurement of jet mass ($M_{\text{jet}}$) in central heavy-ion collisions, introducing a two-dimensional measurement methodology as a function of ($p_{\text{T,jet}}, M_{\text{jet}}$) with R = 0.4 as a jet resolution parameter. The validity of this method is evaluated through the Monte Carlo simulations and closure tests, and initial technical results using STAR data will also be presented.
