Measurement of jet fragmentation in 5.02 TeV proton-lead and proton-proton collisions with the ATLAS detector

Abstract

A measurement of the fragmentation functions of jets into charged particles in p+Pb collisions and ppcollisions is presented. The analysis utilizes 28 nb−1of p+Pb data and 26 pb−1of ppdata, both at √sNN=5.02 TeV, collected in 2013 and 2015, respectively, with the ATLAS detector at the LHC. The measurement is reported in the centre-of-mass frame of the nucleon–nucleon system for jets in the rapidity range |y∗| <1.6 and with transverse momentum 45<pT<260 GeV. Results are presented both as a function of the charged-particle transverse momentum and as a function of the longitudinal momentum fraction of the particle with respect to the jet. The ppfragmentation functions are compared with results from Monte Carlo event generators and two theoretical models. The ratios of the p+Pb to ppfragmentation functions are found to be consistent with unit