Measurement of jet suppression in central Pb-Pb collisions at √sNN=2.76 TeV

Abstract

The transverse momentum (pT) spectrum and nuclear modification factor (RAA) of reconstructed jets in 0–10% and 10–30% central Pb–Pb collisions at View the MathML source were measured. Jets were reconstructed using the anti-kT jet algorithm with a resolution parameter of R=0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet pT spectra are reported in the pseudorapidity interval of |ηjet|<0.5 for View the MathML source in 0–10% and for View the MathML source in 10–30% collisions. Reconstructed jets were required to contain a leading charged particle with pT>5 GeV/c to suppress jets constructed from the combinatorial background in Pb–Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb–Pb collisions had a negligible effect on the RAA. The nuclear modification factor RAA was found to be 0.28±0.04 in 0–10% and 0.35±0.04 in 10–30% collisions, independent of View the MathML source 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.