Abstract
The momentum-weighted sum of the electric charges of particles inside a jet, known as jet charge, is sensitive to the electric charge of the particle initiating the parton shower. This paper presents jet charge distributions in sqrt{s_{mathrm{NN}}} = 5.02 TeV lead-lead (PbPb) and proton-proton (pp) collisions recorded with the CMS detector at the LHC. These data correspond to integrated luminosities of 404 μb−1 and 27.4 pb−1 for PbPb and pp collisions, respectively. Leveraging the sensitivity of the jet charge to fundamental differences in the electric charges of quarks and gluons, the jet charge distributions from simulated events are used as templates to extract the quark- and gluon-like jet fractions from data. The modification of these jet fractions is examined by comparing pp and PbPb data as a function of the overlap of the colliding Pb nuclei (centrality). This measurement tests the color charge dependence of jet energy loss due to interactions with the quark-gluon plasma. No significant modification between different centrality classes and with respect to pp results is observed in the extracted quark- and gluon-like jet fractions.
Highlights
This paper presents jet charge distributions in √sNN = 5.02 TeV lead-lead (PbPb) and proton-proton collisions recorded with the CMS detector at the LHC
This paper presents the first jet charge measurements in heavy ion collisions along with pp jet charge results at the same center-of-mass energy per nucleon pair ( s )
The widths of the jet charge distributions for pp collisions are in good agreement with predictions from the event generator pythia6 and are shown to be independent of PbPb collision centrality
Summary
The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T. Pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter (ECAL), and a brass and scintillator hadron calorimeter (HCAL), each composed of barrel and endcap sections. Events of interest are selected using a two-tiered trigger system [33] In this analysis, jets are reconstructed within the range |η| < 1.5. Within the central barrel region corresponding to |η| < 1.48, the HCAL cells map onto 5 × 5 ECAL crystal arrays to form calorimeter towers projecting radially outwards from the nominal interaction point. The silicon tracker measures charged-particle tracks within |η| < 2.5. It consists of 1440 silicon pixel and 15 148 silicon strip detector modules. A detailed description of the CMS detector, together with a definition of the coordinate system used and the relevant kinematic variables, can be found in ref. [36]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
