Survival of charmonia in a hot environment

Abstract

A colorlesscc dipole emerging from a heavy ion collision and developing the charmonium wave function can be broken-up by final state interactions (FSI) propagating through the hot medium created in the collision. We single out two mechanisms of charmonium attenuation: (i) Debye color screening, called melting; and (ii) color-exchange interaction with the medium, called absorption. The former problem has been treated so far only for charmonia at rest embedded in the medium, while in practice their transverse momenta at the LHC are quite high, p 2 T = 7 − 10 GeV 2 . We demonstrate that acc dipole may have a large survival probability even at infinitely high temperature. We develop a procedure of Lorentz boosting of the Schrödinger equation to a moving reference frame and perform the first realistic calculations of the charmonium survival probability employing the path-integral technique, incorporating both melting and absorption. These effects are found to have comparable magnitudes. We also calculated the FSI suppression factor for the radial excitation ψ(2S) and found it to be stronger than for J/ψ, except large pT , where ψ(2S) is relatively enhanced. The azimuthal asymmetry parameter v2 is also calculated.

The investigation of quark–antiquark potential in a plasma with hyperscaling violation background

“…In this paper calculation of quarkonium binding energies by using a realistic complex-valued potential for both an isotropic and anisotropic quark-gluon plasma has been studied, where the disassociation temperatures of the ground and first excited states considering both the real and imaginary parts of the binding energy have been determined. In, [64] readers consider two mechanisms of charmonium attenuation by considering final state interactions, regarding to the fact that in heavy ion collisions, most of quarkonium observed experimentally are moving through the medium with relativistic velocities. One conclude they have finite probability to survive, even at infinitely high temperature.…”

Detailed rapidity dependence ofJ/ψproduction at energies available at the Large Hadron Collider

“…In the transport model, J/ψ is assumed to move with constant velocity in QGP due to its large mass, this may underestimate its collective flows in high p T bin. New mechanism of interactions between J/ψ and QGP may give additional enhancement of v 2 in Fig.5 [47]. In order to distinguish the J/ψ production mechanisms at different rapidity, I also calculate the ratio of J/ψ mean transverse momentum square in nucleusnucleus collisions to that in proton-proton collisions r AA = p 2 T P bP b / p 2 T pp .…”

Gribov inelastic shadowing in the dipole representation

“…More example of comparison with data can be found in Ref. [22]. Notice also that we did not include any mechanism of nuclear enhancement at x > 0.1, the effect called antishadowing, which affect the small-x region as well.…”