Measurement of correlations between dijet-asymmetry andevent-shape variables in Pb+Pb collisions at $\sqrt{s_{\rm   NN}}$ = 2.76 TeV with the ATLAS detector at the LHC

ATLAS Collaboration

Preprint/Internal Report

PUBDB-2015-03494

Measurement of correlations between dijet-asymmetry andevent-shape variables in Pb+Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with the ATLAS detector at the LHC

ATLAS Collaboration (Collaboration author)DESY*

2015

Report No.: ATLAS-CONF-2015-021

Abstract: The variation of the dijet asymmetry with the angle between the leading jet and the second order event-plane in Pb+Pb collisions at sNN−−−√=2.76 TeV is investigated using the ATLAS detector at the LHC. This measurement is extended by constraining the shape of the collision geometry by selecting events based on the magnitude of the second-order flow harmonic. These measurements study the path-length dependence of the dijet asymmetry by requiring the jet pair to traverse different lengths of the medium. A weak dependence of the asymmetry on the angle between the leading jet and the second order event-plane is observed. The asymmetry is systematically larger out-of-plane, where jets traverse on average, a longer path-length in the medium than in-plane, where the path-length is shorter. These results can shed light on the energy-loss mechanism, in which hard-scattered partons lose energy while traversing the hot and dense medium produced in heavy ion collisions

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