Impact of momentum space anisotropy on heavy quark dynamics in a QGP medium

Abstract

Momentum space anisotropy present in the quark and gluon distribution functions in relativistic heavy ion collisions induces Chromo-Weibel instability in the hot QCD medium created therein. The impact of the Chromo-Weibel instability on the dynamics of a heavy-quark (HQ) traversing in the QGP medium is investigated within the framework of kinetic theory by studying the momentum and temperature behavior of HQ drag and diffusion coefficients. The physics of anisotropy is captured in an effective Vlasov term in the transport equation. The effects of the instability are handled by making a relation with the phenomenologically known jet quenching parameter in RHIC and LHC. Interestingly, the presence of instability significantly affect the temperature and momentum dependences of the HQ drag and diffusion coefficients. These results may have appreciable impact on the experimental observables such as, the nuclear suppression factor, RAA(pT ), and the elliptic flow, v2(pT ), of heavy mesons in heavy ion collisions at RHIC and LHC energies which is a matter of future investigation.

Collective excitations of hot QCD medium in a quasiparticle description

“…In a very recent work, Mitra and Chandra [30] estimated the electrical conductivity and charge diffusion coefficients employing EQPM. The EQPM has also served as basis to incorporate hot QCD medium effects while investigating heavyquark transport in isotropic [34] and anisotropic [33] along with quarkonia in hot QCD medium [31,32] and thermal particle production [35,36]. However, the above model calculations were not able to exactly yield the shear and bulk viscosities phenomenologically extracted from the hydrodynamic simulations of the QGP [3,4], consistently agreeing with different experimental observables measured such as the multiplicity, transverse momentum spectra and the integrated flow harmonics of charged hadrons.…”

Impact of momentum anisotropy and turbulent chromo-fields on thermal particle production in quark–gluon-plasma medium

“…As will be seen in the later part of the manuscript, such effects indeed play a significant role and cannot simply be ignored for the momenta and temperatures accessible in RHIC. It is to be mentioned that such anisotropy induced momentum distributions have already been exploited to investigate the heavy-quark dynamics in the QGP medium [42,43]. The heavy-quark dynamics gets a significant impact from such effects.…”

“…The hot QCD medium effects enter through the quasi-particle distribution functions along with the non-trivial energy dispersions. The near-equilibrium quasi-quark and quasi-gluon distributions that are employed here were obtained earlier in [42,43] and utilized in the context of studying heavyquark dynamics in the anisotropic QGP/QCD medium. In this work, we employ them in exploring the dilepton production from the thermal QGP medium following the kinetic theory description of the dilepton production by qq annihilation at leading order within a (1 + 1)d boost invariant expansion of the thermal QGP medium in longitudinal direction.…”

“…This could be done by first modeling the non-equilibrium momentum distribution functions [42,43] that describe the expanding anisotropic QGP, followed by employing it to the kinetic theory description of dilepton production in the QGP medium. Our formalism is a straightforward extension of Refs.…”

Heavy quarks in turbulent QCD plasmas

“…At the end of the introductory remarks we note that an approach similar to ours, which was also inspired by the electromagnetic plasma studies [13], was formulated in [14], see [15,16] as well. We also mention an attempt [17] to study transport of heavy quarks in a plasma populated by strong chromodynamic fields.…”