Measurement of jet suppression in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV

Abstract

The transverse momentum ($p_{\mathrm{T}}$) spectrum and nuclear modification factor ($R_{\mathrm{AA}}$) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV were measured. Jets were reconstructed from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal), with the anti-$k_{\mathrm{T}}$ jet algorithm with a resolution parameter of R=0.2. The jet $p_{\mathrm{T}}$ spectra are reported in the pseudorapidity interval of $|{\eta }_{\mathrm{jet}}|<0.5$ for $40<p_{\mathrm{T},\mathrm{jet}}<120$ GeV/$c$ in 0-10% and for $30<p_{\mathrm{T},\mathrm{jet}}<100$ GeV/$c$ in 10-30% collisions. Reconstructed jets were required to contain a leading charged particle with $p_{\mathrm{T}}>5$ GeV/$c$ to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The effect of the leading charged particle requirement has been studied in both pp and Pb-Pb collisions and has been shown to have negligible effects on the $R_{\mathrm{AA}}$ within the uncertainties of the measurement. The nuclear modification factor is obtained by dividing the jet spectrum measured in Pb-Pb by that in pp collisions scaled by the number of independent nucleon-nucleon collisions estimated using a Glauber model. $R_{\mathrm{AA}}$ is found to be $0.28\pm 0.04$ in 0-10% and $0.35\pm 0.04$ in 10-30% collisions, independent of $p_{\mathrm{T},\mathrm{jet}}$ within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching.

27 pages, 5 captioned figures, 1 table, authors from page 21, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/1197

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Cited by in corpus (4)

• Decomposing transverse momentum balance contributions for quenched jets in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
• Jet-like correlations with neutral pion triggers in pp and central Pb-Pb collisions at 2.76 TeV
• An overview of experimental results from ultra-relativistic heavy-ion collisions at the CERN LHC: hard probes
• The nuclear modification of charged particles in Pb-Pb at $\sqrt{{\text{s}}_{\text{NN}}}=\text{5.02}\text{TeV}$ measured with ALICE