Study of quark- and gluon-like jet fractions using jet charge in PbPb and pp collisions at 5.02 TeV

The momentum-weighted sum of the electric charges of particles inside a jet, known as jet charge, is sensitive to the charge of the particle initiating the parton shower. This note presents jet charge distributions in $5.0~\mathrm{TeV}$ PbPb and pp collisions recorded by the CMS detector at the LHC. These data correspond to integrated luminosities of $404~\mu\mathrm{b^{-1}}$ and $27.4~\mathrm{pb^{-1}}$ for PbPb and pp collisions, respectively. The measurements are unfolded to account for detector and background effects. Leveraging the jet charge's sensitivity to fundamental differences in the electric charges of quarks and gluons, a template-fitting method is proposed to estimate the quark- and gluon-like jet fractions of an inclusive jet sample. Using the jet charge distributions from simulated events as templates, the quark and gluon jet fractions are extracted from data. The modification of these jet fractions is examined by comparing PbPb and pp data as a function of collision centrality. This measurement tests the color charge dependence of jet energy loss due to interactions with the quark-gluon plasma.