Medium-induced gluon radiation with full resummation of multiple scatterings for realistic parton-medium interactions

Abstract

The new precision era of jet quenching observables at both RHIC and the LHC calls for an improved and more precise description of in-medium gluon emissions. The development of new theoretical tools and analytical calculations to tackle this challenge has been hampered by the inability to include the effects of multiple scatterings with the medium using a realistic model for the parton-medium interactions. In this paper, we show how the analytical expressions for the full in-medium spectrum, including the resummation of all multiple scatterings, can be written in a form where the numerical evaluation can be easily performed without the need of the usually employed harmonic or single hard approximations. We present the transverse momentum and energy-dependent mediuminduced gluon emission distributions for known realistic interaction models to illustrate how our framework can be applied beyond the limited kinematic regions of previous calculations.

Leading jets and energy loss

“…The concept of jet or parton energy loss has played an important role in theoretical calculations of jet quenching in heavy-ion collisions [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. Typically, the notion of energy loss is defined in the soft gluon approximation where flavor-changing processes are suppressed, and calculations are performed in the lowest non-trivial fixed order or resummed expansions.…”

“…The dependence of the energy loss mechanism on the parton flavor has been discussed extensively in the literature -in particular in the context of jet quenching studies in heavy-ion collisions [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. While we only focus on vacuum energy loss in this work, our results set the baseline for studies of energy loss in the nuclear medium.…”

Medium-induced fragmentation and equilibration of highly energetic partons

“…Starting with the original calculations of the rates for medium-induced radiation [12][13][14][15][16] and more recent refinements [17][18][19][20][21][22][23], there have been several theoretical studies tackling the description of the jet evolution in QCD medium, based on (semi-)analytic approaches [24][25][26], effective kinetic descriptions [27][28][29][30][31][32] as well as sophisticated Monte Carlo simulations [33][34][35][36][37][38][39][40] some of which even include a fully coupled jet-medium evolution. Although, all of these approaches provide a solid description of experimental measurements in their respective range of applicability, a general challenge in the description of in-medium jet evolution is to devise a consistent simultaneous description of the near-thermal soft and hard constituents of the jet.…”

Medium induced QCD cascades: broadening and rescattering during branching

“…For other approach which addresses the transverse-momentum dependence but neglects the large-x parton's spectrum see the relaxing harmonic approximation of ref [30]…”