Phenomenological impact of the additional octet collision term

Quantify the phenomenological impact of the additional octet–octet collision term, which describes transitions within the continuum of octet scattering states, by solving the coupled singlet–octet Boltzmann transport equations for in-medium quarkonium.

Background

The paper derives singlet–octet Boltzmann equations from the universal Lindblad equation and compares them with the equations obtained from the Davies secular equation by Yao et al. In the small-dipole limit, the universal-Lindblad derivation produces an additional octet–octet collision term that describes transitions among continuum octet scattering states.

This term is absent from the rotating-wave- or secular-approximation-based transport equations because the continuous octet spectrum permits arbitrarily close transition energies, for which the secular approximation is not uniformly justified. The authors state that the additional term may affect the approach to equilibrium and the thermalization time scale, but its quantitative phenomenological consequences are unresolved because the coupled transport equations have not yet been solved for realistic dynamics.