Measurement of inclusive jet charged particle fragmentation functions in Pb+Pb collisions at sqrt(s(nn)) = 2.76 TeV with the ATLAS detector

Measurements of charged particle fragmentation functions of jets produced in ultra-relativistic nuclear collisions are expected to provide insight on the modification of parton showers in the hot, dense medium created in the collisions. ATLAS has measured jets in sqrt(s(nn)) = 2.76 TeV Pb+Pb collisions using a data set recorded in 2011 with an integrated luminosity of 0.14 inverse nanobarns. Jets were reconstructed using the anti-kt algorithm with distance parameter values R = 0.2, 0.3, and 0.4. Distributions of charged particle transverse momentum and longitudinal momentum fraction, z, are reported for seven bins in collision centrality for jet pT > 85, 92, and 100 GeV, respectively, for R = 0.2, 0.3, and 0.4. Ratios of fragmentation spectra to the spectra in the 60-80% central bin are presented. Those ratios show a reduction of fragment yield in central collisions relative to the 60-80% bin at intermediate z values, 0.05 < z < 0.2 and an enhancement in fragment yield for z < 0.05. No significant modification is observed at large z.