Modification of jet shapes in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

CMS Collaboration [--] Quertenmont, Loic [UCL] Basegmez, Suzan [UCL] Beluffi, Camille [UCL] Bruno, Giacomo [UCL] Castello, Roberto [UCL] Caudron, Adrien [UCL] Ceard, Ludivine [UCL] Da Silveira, Gustavo Gil [UCL] Delaere, Christophe [UCL] Du Pree, Tristan [UCL] Favart, Denis [UCL] Forthomme, Laurent [UCL] Giammanco, Andrea [UCL] Hollar, Jonathan [UCL] Jez, Pavel [UCL] Lemaitre, Vincent [UCL] Liao, Junhui [--] Militaru, Otilia [--] Nuttens, Claude [UCL] Pagano, Davide [UCL] Pin, Arnaud [UCL] Piotrzkowski, Krzysztof [UCL] Popov, Andrey [UCL] Selvaggi, Michele [UCL] Vidal Maroño, Miguel [UCL] Vizan Garcia, Jesús Manuel [UCL] et al.[show all]

The first measurement of jet shapes, defined as the fractional transverse momentum radial distribution, for inclusive jets produced in heavy-ion collisions is presented. Data samples of PbPb and pp collisions, corresponding to integrated luminosities of 150 μb−1 and 5.3 pb−1 respectively, were collected at a nucleon–nucleon centre-of-mass energy of View the MathML sourcesNN=2.76 TeV with the CMS detector at the LHC. The jets are reconstructed with the anti-kTkT algorithm with a distance parameter R=0.3R=0.3, and the jet shapes are measured for charged particles with transverse momentum pT>1 GeV/cpT>1 GeV/c. The jet shapes measured in PbPb collisions in different collision centralities are compared to reference distributions based on the pp data. A centrality-dependent modification of the jet shapes is observed in the more central PbPb collisions, indicating a redistribution of the energy inside the jet cone. This measurement provides information about the parton shower mechanism in the hot and dense medium produced in heavy-ion collisions.