Theoretical Developments for Jets in Heavy-Ion Collisions

TL;DR

This paper develops theoretical methods to compute quantum corrections affecting how jets lose energy and change momentum when passing through quark-gluon plasma in heavy-ion collisions.

Contribution

It introduces new calculations for logarithmic corrections to jet quenching parameters using thermal field theory, advancing understanding of jet-medium interactions.

Findings

Logarithmic corrections to transverse momentum broadening computed

Matching calculations remove unphysical divergences in jet mass

Progress towards two-loop quantum corrections for jet mass

Abstract

The quark-gluon plasma (QGP) is an exotic phase of matter, composed of deconfined quarks and gluons and is briefly created in heavy-ion collisions (HIC) at the LHC and at the RHIC. High-energy, self-collimated structures of final-state particles also created in HIC, called jets, probe the QGP, piercing through it on their way to the particle detector. Quantum field theory at finite temperature or thermal field theory, is then an extremely powerful tool, capable of analytically quantifying how such a high-energy object interacts with a weakly coupled thermal bath. In this thesis, we work towards the computation of corrections to two quantities, which dictate how jets are quenched by the QGP. The first being the transverse momentum broadening coefficient, which describes how the jet diffuses in transverse momentum space through its interaction with the medium. We focus on the computation of logarithmically enhanced corrections, carefully showing how the thermal scale affects the logarithmic phase space. The second is the asymptotic mass, which can be thought of as a shift in the jet dispersion relation as it undergoes forward scattering with the medium. We complete a matching calculation, which rids the mass' classical corrections of any unphysical divergences, while also beginning the completion of its full two-loop, quantum corrections.