Probing the multi-scale dynamical interaction between heavy quarks and the QGP using JETSCAPE

Abstract

The dynamics of shower development for a jet traveling through the QGP involves a variety ofscales, one of them being the heavy quark mass. Even though the mass of the heavy quarksplays a subdominant role during the high virtuality portion of the jet evolution, it does affectlongitudinal drag and diffusion, stimulating additional radiation from heavy quarks. Theseemissions partially compensate the reduction in radiation from the dead cone effect. In the lowervirtuality part of the shower, when the mass is comparable to the transverse momenta of thepartons, scattering and radiation processes off heavy quarks differ from those off light quarks. Allthese factors result in a different nuclear modification factor for heavy versus light flavors and thusfor heavy-flavor tagged jets.In this study, the heavy quark shower evolution and the fluid dynamical medium are modeledon an event by event basis using the JETSCAPE Framework. We present a multi-stagecalculation that explores the differences between various heavy quark energy-loss mechanismswithin a realistically expanding quark-gluon plasma (QGP). Inside the QGP, the highly virtualand energetic portion of the shower is modeled using the MATTER generator, while the LBTgenerator models the showers induced by energetic and close-to-on-shell heavy quarks. Energy-momentum exchange with the medium, essential for the study of jet modification, proceeds usinga weak coupling recoil approach. The JETSCAPE framework allows for transitions, on the levelof individual partons, from one energy-loss prescription to the other depending on the parton’senergy and virtuality and the local density. This allows us to explore the effect and interplaybetween the different regimes of energy loss on the propagation and radiation from hard heavyquarks in a dense medium.