Holographic Jet Shapes and their Evolution in Strongly Coupled Plasma

摘要

Recently our group analyzed how the probability distribution for the jetopening angle is modified in an ensemble of jets that has propagated through anexpanding cooling droplet of plasma [1]. Each jet in the ensemble isrepresented holographically by a string in the dual 4+1- dimensionalgravitational theory with the distribution of initial energies and openingangles in the ensemble given by perturbative QCD. In [1], the full stringdynamics were approximated by assuming that the string moves at the speed oflight. We are now able to analyze the full string dynamics for a range ofpossible initial conditions, giving us access to the dynamics of holographicjets just after their creation. The nullification timescale and the features ofthe string when it has nullified are all results of the string evolution. Thisemboldens us to analyze the full jet shape modification, rather than just theopening angle modification of each jet in the ensemble as in [1]. We find theresult that the jet shape scales with the opening angle at any particularenergy. We construct an ensemble of dijets with energies and energy asymmetrydistributions taken from events in proton-proton collisions, opening angledistribution as in [1], and jet shape taken from proton-proton collisions andscaled according to our result. We study how these observables are modifiedafter we send the ensemble of dijets through the strongly-coupled plasma.