Remarks on the possible importance of jet v_3 and multiple jet production for the interpretation of recent jet quenching measurements at the LHC

TL;DR

This paper explores how jet v_3 and multiple jet production might influence the interpretation of recent LHC jet quenching data, suggesting these factors could explain the observed soft particle excess at large angles.

Contribution

It introduces the potential roles of jet v_3 and multiple jet production in understanding jet quenching measurements, highlighting factors often overlooked in conventional models.

Findings

Large jet v_3 could contribute to soft particle excess.

Multiple jets near the leading jet may bias di-jet measurements.

These effects challenge traditional energy loss models.

Abstract

Recent jet quenching measurements in Pb+Pb collisions at the LHC report a significant energy imbalance of di-jets. The imbalance is found to be compensated by a large amount of soft particles produced at large angles with respect to the di-jet axis. This observation questions the conventional picture of parton energy loss models, established at RHIC, which typically expect that the radiated gluons are emitted at moderate angles close to the outgoing parton. In this letter, we qualitatively discuss two possible contributions of the underlying heavy-ion background that may have to be taken into account when interpreting the recent data. We show that a large jet v_3, potentially caused by a pathlength dependent energy loss in the presence of fluctuating initial conditions, could contribute to the observed excess of soft particles apparently originating from large angle in-medium radiation. In addition, the observed excess could also be induced by multiple jets produced in the vicinity of the leading jet, caused by a potential selection bias imposed on the di-jet momentum imbalance.