Results of a systematic study of dijet suppression measured at the BNL Relativistic Heavy Ion Collider

Abstract

Background: There has been much recent investigation into dijets at the LHC, predictions for dijets at RHIC scales are lacking.Purpose: We present a systematic study of the dijet suppression at RHIC using the VNI/BMS parton cascade. Methods:We examine the modification of the dijet asymmetry Aj and the within-cone transverse energy distribution (jet-shape) along with partonic fragmentation distributions z and jt in terms of:q; the path length of leading and sub-leading jets; cuts on the jet energy distributions; jet cone angle and the jet-medium interaction mechanism.Results: We find that Aj is most sensitive toq and relatively insensitive to the nature of the jet-medium interaction mechanism. The jet profile is dominated byq and the nature of the interaction mechanism. The partonic fragmentation distributions clearly show the jet modification and differentiate between elastic and radiative+elastic modes.Conclusions: Dijets at RHIC scales are strongly modified by a QGP medium, measurements of their suppression will provide a vital additional data point for understanding the modification of hard probes.

Origins of the di-jet asymmetry in heavy-ion collisions

“…For instance, strong surface bias is found in [51], while there is hardly any in [47] (this is not in contradiction to our findings, as this model does not contain energy loss fluctuations). The authors of [49,50] notice that the asymmetry of the configuration entering the medium plays a role.…”

“…Although a number of different models [26,31,34,35,[47][48][49][50][51][52] have successfully reproduced measurements of the dijet asymmetry the situation on the theory side has so far been inconclusive. For instance, strong surface bias is found in [51], while there is hardly any in [47] (this is not in contradiction to our findings, as this model does not contain energy loss fluctuations).…”

The parton cascade BAMPS with the improved Gunion-Bertsch matrix element

“…For further understanding the energy loss of high p t particles and especially its path-length dependence we are currently investigating the implementation of a stochastic LPM effect similar to [35,36]. This would allow further constraints for the implemented LPM parameter X LPM .…”

Operator definition and derivation of collisional energy and momentum loss in relativistic plasmas

“…Collisional effects, such as energy loss and hadron dissociation, may play a role in heavy flavor quenching [15][16][17][18][19]. The cumulative effect of collisional energy loss is also amplified in a parton shower and can be studied in jet observables [20][21][22][23][24], especially for large radii R [25].…”