Propagation of charm quarks in equilibrating quark-gluon plasma

Abstract

We study the propagation of charm quarks, produced from the initial fusion of partons, in an equilibrating quark-gluon plasma which may be formed in the wake of relativistic collisions of gold nuclei. Initial conditions are taken from a self screened parton cascade model and the chemical equilibration is assumed to proceed via gluon multiplication and quark production. The energy loss suffered by the charm quarks is obtained by evaluating the drag force generated by the scattering with quarks and gluons in the medium. We find that the charm quarks may loose only about 10% of their initial energy in conditions likely to be attained at the Relativistic Heavy Ion Collider, while they may loose up to 40% of their energy while propagating in the plasma created at Large Hadron Collider. We discuss the implications for signals of quark gluon plasma.

Thermalization of heavy quarks in the quark-gluon plasma

“…[24], which confirms the findings of Ref. [27]. here is that for resonant rescattering both are increased by a substantial factor (∼3) over the pQCD results.…”

“…The main finding 2 As pointed out in Ref. [27] the use of quantum distribution functions (Bose-Einstein and Fermi-Dirac) induces moderate corrections to the drag and diffusion coefficients obtained from pQCD rescattering; this is still true for the "D"-meson resonance interactions as they involve contributions from thermal antiquarks only, which, at the temperatures under consideration, are mostly nondegenerate. For example, at T = 300 MeV, the deviations when using Fermi distributions amount to ∼20% uncertainties associated with the resonance parameters, as discussed in the following.…”

“…2 After integrating over the four-momentum-conserving δ function, and making use of Lorentz invariance of the matrix elements, we can reduce the expressions for the scalar coefficients, Eqs. (25)- (27), to numerically tractable three-dimensional integrals. 3 The temperature and momentum dependencies of the A and B 0 coefficients are summarized in Fig.…”

“…With a strong coupling constant α s = 0.6, rather short relaxation times of around ∼4 fm/c have been found for a massless QGP at temperatures T 400 MeV. However, since the relaxation times are essentially proportional to α −2 s , more moderate values of α s (e.g., 0.3) lead to a significant increase (by a factor of 3-4), rendering thermalization of c quarks under RHIC conditions unlikely [27]. This is also consistent with recent transport studies [28,29].…”

Charmonia enhancement in quark–gluon plasma with improved description of c-quarks phase distribution

“…Following [2,3], the c andc quarks distributions in the QGP are assumed to follow a Fokker-Planck (FP) equation in momentum space.…”