Towards the understanding of jet substructures and cross sections in heavy ion collisions using soft collinear effective theory

TL;DR

This paper uses soft collinear effective theory to calculate jet shapes and cross sections in proton-proton and heavy ion collisions, revealing medium effects and achieving good agreement with LHC data.

Contribution

It introduces a theoretical framework combining SCET with Glauber gluons to accurately predict jet substructure modifications in heavy ion collisions.

Findings

Resummation of large logarithms improves prediction accuracy.

Medium induces significant power corrections to jet shapes.

Theoretical results agree well with recent LHC measurements.

Abstract

The jet quenching phenomenon in heavy ion collisions provides a strong evidence of the modification of parton shower in the quark-gluon plasma (QGP). Jet substructure observables can probe various aspects of the jet formation mechanism. They contain useful information about the QGP and allow us to study the medium properties in great details. Here we present theoretical calculations of jet shapes and cross sections in proton-proton and lead-lead collisions at the LHC using soft-collinear effective theory, with Glauber gluon interactions in the medium. We find that resumming large logarithms in the jet substructure calculation is necessary for precise theoretical predictions. The resummation is performed using renormalization group evolution between characteristic jet scales. We also find that the medium induces power corrections to jet shapes. In the end we present the comparison between our calculations with the recent measurements at the LHC with very good agreement. Our calculations help initiate precise jet modification studies in heavy ion collisions.