We report the measurement of a new observable of jet quenching in central Pb-Pb collisions at √sNN = 2.76 TeV, based on the semi-inclusive rate of charged jets recoiling from a high transverse momentum (high-pT) charged hadron trigger. Jets are measured using collinear-safe jet reconstruction with infrared cutoff for jet constituents of 0.15 GeV, for jet resolution parameters R = 0.2, 0.4 and 0.5. Underlying event background is corrected at the event-ensemble level, without imposing bias on the jet population. Recoil jet spectra are reported in the range 20

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.

Inclusive jet spectra from pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV, collected with the CMS detector at the LHC, are presented. Jets are reconstructed with three different distance parameters for transverse momentum ($p_{\mathrm{T}}$) greater than 70 GeV/$c$ and pseudorapidity $

Experimental measurements from dihadron correlations triggered with very high-p[subscript]T particles in Pb+Pb collisions at 2.76 TeV are shown. The data set was collected by the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) and corresponds to an integrated luminosity of 150 [mu]b−1. The use of high-p[subscript]T track triggers made it possible to study dihadron correlations up to p[subscript]T ~ 50 GeV/c. The presence of azimuthal anisotropies of final state particles in non-central Pb+Pb collisions gives rise to single-particle correlations that are characterized by the Fourier harmonics, v[subscript]n. To isolate the jet components of the correlations, the v2-v4 components are subtracted from the correlations and the per-trigger-particle associated-yields on the near and away side are studied. The data are compared to correlations from p+p collisions at the same center-of-mass energy over a wide range of trigger and associated-particle p[subscript]T and as a function of Pb+Pb event centrality. On the near-side there is evidence of moderate enhancement at low p[superscript]assc [subscript]T. On the away side there is a significant enhancement at p[superscript]assc [subscript]T ~ 0.5 GeV/c and at higher transverse momentum, p[superscript]assc [subscript]T > 3 GeV/c, there is a suppression of about 50% compared to p+p collisions.