Heavy flavor at the large hadron collider in a strong coupling approach

Min He,Rainer J Fries,Ralf Rapp

doi:10.1016/j.physletb.2014.05.050

Min He, Rainer J Fries + Show 1 more

Open Access

https://doi.org/10.1016/j.physletb.2014.05.050

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Abstract

Employing nonperturbative transport coefficients for heavy-flavor (HF) diffusion through quark–gluon plasma (QGP), hadronization and hadronic matter, we compute D- and B-meson observables in Pb+Pb (s=2.76 TeV) collisions at the LHC. Elastic heavy-quark scattering in the QGP is evaluated within a thermodynamic T-matrix approach, generating resonances close to the critical temperature which are utilized for recombination into D and B mesons, followed by hadronic diffusion using effective hadronic scattering amplitudes. The transport coefficients are implemented via Fokker–Planck Langevin dynamics within hydrodynamic simulations of the bulk medium in nuclear collisions. The hydro expansion is quantitatively constrained by transverse-momentum spectra and elliptic flow of light hadrons. Our approach thus incorporates the paradigm of a strongly coupled medium in both bulk and HF dynamics throughout the thermal evolution of the system. At low and intermediate pT, HF observables at LHC are reasonably well accounted for, while discrepancies at high pT are indicative for radiative mechanisms not included in our approach.

Highlights

Open heavy-flavor (HF) observables have developed into a key probe of the hot nuclear medium produced in ultrarelativistic heavy-ion collisions (URHICs) [1]
Once charm (c) and bottom (b) quarks are produced in primordial nucleon-nucleon collisions, their large masses suppress inelastic reinteractions, rendering their subsequent diffusion a quantitative tool to determine the thermalization timescale in the medium. Since this timescale appears to be comparable to the typical lifetime of the fireball formed in URHICs, the modifications imprinted on the final HF spectra provide a direct measure of the coupling strength to the medium
In the quark-gluon p√lasma (QGP), we focus on the results using the internal energy, as the pertinent T -matrices lead to better agreement with the thermal lattice QCD (lQCD) “data” for quarkonium correlators and HQ susceptibilities [32, 37]

Summary

Introduction

Open heavy-flavor (HF) observables have developed into a key probe of the hot nuclear medium produced in ultrarelativistic heavy-ion collisions (URHICs) [1]. Once charm (c) and bottom (b) quarks are produced in primordial nucleon-nucleon collisions, their large masses suppress inelastic reinteractions, rendering their subsequent diffusion a quantitative tool to determine the thermalization timescale in the medium Since this timescale appears to be comparable to the typical lifetime of the fireball formed in URHICs, the modifications imprinted on the final HF spectra provide a direct measure of the coupling strength to the medium. In the present paper we conduct a systematic comparison of our earlier constructed transport approach for open HF [14, 15] to available observables at the LHC This approach implements a strong-coupling scheme in both micro- and macrophysics (i.e., HF transport and bulk evolution, respectively) of QGP and hadronic matter, and has been found to describe HF data at RHIC fairly well [14, 15].

Non-Perturbative HF Transport

HF Observables at LHC

Findings

Summary