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 inverse microbarns and 5.3 inverse picobarns respectively,were collected at a nucleon-nucleon centre-of-mass energy of sqrt(s[NN]) = 2.76 TeV with the CMS detector at the LHC. The jets are reconstructed with the anti-kt algorithm with a distance parameter R=0.3,and the jet shapes are measured for charged particles with transverse momentum pt>1 GeV. 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.
Modification of jet shapes in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
CAVALLO, Nicola;FABOZZI, FRANCESCO;
2014-01-01
Abstract
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 inverse microbarns and 5.3 inverse picobarns respectively,were collected at a nucleon-nucleon centre-of-mass energy of sqrt(s[NN]) = 2.76 TeV with the CMS detector at the LHC. The jets are reconstructed with the anti-kt algorithm with a distance parameter R=0.3,and the jet shapes are measured for charged particles with transverse momentum pt>1 GeV. 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
