Influence of multiple in-medium scattering processes on the momentum imbalance of reconstructed di-jets

TL;DR

This paper uses the BAMPS transport model to study how multiple in-medium scatterings affect the momentum imbalance of reconstructed di-jets in heavy-ion collisions, providing insights into partonic energy loss mechanisms.

Contribution

It introduces a new method within BAMPS to simulate the full evolution of jet showers, including medium recoil, enabling detailed analysis of jet quenching effects.

Findings

Medium recoil significantly influences jet momentum imbalance.

Partonic in-medium path length differences affect jet energy loss.

The method allows detailed tracking of jet evolution in the medium.

Abstract

Experimental data measured in sqrt(s)=2.76 TeV Pb+Pb collisions at the LHC show a significant enhancement of events with an unbalanced pair of reconstructed jet momenta in comparison with p+p collisions. This enhancement of momentum imbalance is supposed to be caused by the different momentum loss of the initial back-to-back di-partons by scatterings within the created dense medium. For investigating the underlying partonic momentum loss we employ the on-shell transport model BAMPS (Boltzmann Approach for Multi-Parton Scattering) for full heavy-ion collisions, which numerically solves the 3+1D Boltzmann equation based on 2->2 as well as inelastic 2<->3 scattering processes, together with PYTHIA initial state conditions for the parton showers. Due to the employed test-particle approach jet reconstruction within BAMPS events is not trivial. We introduce a method that nevertheless allows the microscopic simulation of the full evolution of the shower particles, recoiled medium particles, and the underlying bulk medium in one common microscopic framework. With this method it is possible to investigate the role of the medium recoil for the momentum imbalance A_J while using well-established background subtraction algorithms. Due to the available particle information in configuration as well as momentum space within BAMPS, it is additionally possible to reproduce the entire evolution of the reconstructed jets within the medium. With this information we investigate the sensitivity of the jet momentum loss from the difference in the partonic in-medium path lengths.