Inclusive jet and charged hadron nuclear modification factors in PbPb collisions at 2.76 TeV with CMS

Measurements are reported for charged hadron and inclusive jet transverse momentum ($p_{\mathrm{T}}$) spectra in pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV with the CMS detector. These measurements make use of the high-statistics jet-triggered data recorded in 2011, including the total available PbPb luminosity of 150$\mu\mathrm{b}^{-1}$ Charged particles are reconstructed using an iterative algorithm and spurious high-$p_{\mathrm{T}}$ tracks are suppressed by requiring appropriate energy deposits in the calorimeter system. Jets are reconstructed with the anti-$k_\mathrm{T}$ algorithm, using combined information from tracking and calorimetry. The charged particle $p_{\mathrm{T}}$ distributions are measured in the pseudorapidity range of $\mid\eta\mid<1$, and $p_{\mathrm{T}}$ up to 100 GeV/$c$. The jet $p_{\mathrm{T}}$ distributions are measured in the pseudorapidity range of $\mid\eta\mid<2$, and $p_{\mathrm{T}}$ from 100 to 300 GeV/$c$. The nuclear modification factors, $\mathrm{R}_{\mathrm{AA}}$, for charged hadrons and jets are presented as a function of $p_{\mathrm{T}}$ and collision centrality. In the range $p_{\mathrm{T}}$ = 5-10 GeV/$c$ the charged hadron production in PbPb collisions is suppressed by up to a factor of seven, compared to the pp yield scaled by the number of incoherent nucleon-nucleon collisions. The charged hadron $\mathrm{R}_{\mathrm{AA}}$ increases at higher $p_{\mathrm{T}}$ and approaches a value of approximately 0.5 in the range $p_{\mathrm{T}}$ = 40-100 GeV/$c$ for the most central collisions.