Abstract
The jet fragmentation function of inclusive jets with transverse momentum pt above 100 GeV in PbPb collisions has been measured using reconstructed charged particles with pt above 1 GeV in a cone of radius 0.3 around the jet axis. A data sample of PbPb collisions collected in 2011 at a nucleon-nucleon center-of-mass energy of sqrt(s[NN]) = 2.76 TeV corresponding to an integrated luminosity of 150 inverse microbarns is used. The results for PbPb collisions as a function of collision centrality and jet transverse momentum are compared to reference distributions based on pp data collected at the same center-of-mass energy in 2013, with an integrated luminosity of 5.3 inverse picobarns. A centrality-dependent modification of the fragmentation function is found. For the most central collisions, a significant enhancement is observed in the PbPb / pp fragmentation function ratio for charged particles with pt less than 3 GeV. This enhancement is observed for all jet pt bins studied.
Highlights
High-energy collisions of heavy ions provide an important experimental tool to study the puzzles of confinement and chiral symmetry breaking in quantum chromodynamics (QCD), the theory of strong interactions
The CMS high-level trigger (HLT) system is used to select PbPb collision events containing high-pT jets reconstructed from calorimeter towers
Monte Carlo (MC) simulations have been used primarily for evaluation of reconstruction performance, in determination of tracking efficiency, and jet energy response and resolution. These studies mostly used QCD jet events simulated by the PYTHIA MC generator [24] [25]
Summary
High-energy collisions of heavy ions provide an important experimental tool to study the puzzles of confinement and chiral symmetry breaking in quantum chromodynamics (QCD), the theory of strong interactions. Study of the fragmentation function provides an important experimental check on the validity of the assumed jet fragmentation in heavy-ion collisions These results can be used to directly connect jet observables to measurements of high-pT particles. The goal of this analysis is to measure the jet fragmentation function in heavy-ion collisions using reconstructed jets. Taking advantage of the higher integrated luminosity (150 μb for PbPb and 5.3 pb−1 for the pp reference data), the measurement is carried out in more differential centrality bins, and as a function of jet pT. This measurement complements the previously published observation of a modification of the transverse profile of the jet in PbPb [19], using the same 2011 and 2013 data
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
