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Title: Measurement of jet quenching with semi-inclusive hadron-jet distributions in central Pb-Pb collisions at $$\sqrt{s_{\mathrm{NN}}}=2.76$$ TeV

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-p T) 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 < p T,jet ch < 100 GeV. Reference distributions for pp collisions at √s = 2.76TeV are calculated using Monte Carlo and NLO pQCD methods, which are validated by comparing with measurements in pp collisions at √s = 7TeV. The recoil jet yield in central Pb-Pb collisions is found to be suppressed relative to that in pp collisions. No significant medium-induced broadening of the intra-jet energy profile is observed within 0.5 radians relative to the recoil jet axis. The angular distribution of the recoil jet yield relative to the trigger axis is found to be similar in central Pb-Pb and pp collisions, with no significant medium-induced acoplanarity observed. Lastly, large-anglemore » jet deflection, which may provide a direct probe of the nature of the quasi-particles in hot QCD matter, is explored.« less
Authors:
 [1]
  1. Czech Technical University in Prague (Czech Republic). Faculty of Nuclear Sciences and Physical Engineering. et al.
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2015; Journal Issue: 9; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Contributing Orgs:
The ALICE collaboration
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quark gluon plasma; Jet physics; Heavy Ions
OSTI Identifier:
1339377