  We study the relaxation time required for the alignment between the spin of a
finite-mass quark/antiquark and the thermal vorticity, at finite temperature
and baryon chemical potential, in the context of relativistic heavy-ion
collisions. The relaxation time is computed as the inverse of the total
reaction rate that in turn is obtained from the imaginary part of the
quark/antiquark self-energy. We model the interaction between spin and thermal
vorticity within the medium by means of a vertex coupling quarks and thermal
gluons that, for a uniform temperature, is proportional to the global angular
velocity and inversely proportional to the temperature. We use realistic
estimates for the angular velocities for different collision energies and show
that the effect of the quark mass is to reduce the relaxation times as compared
to the massless quark case. Using these relaxation times we estimate the
intrinsic quark and antiquark polarizations produced by the thermal vorticity.
We conclude by pointing out that, in spite of the former being larger than the
latter, it is still possible to understand recent results from the STAR Beam
Energy Scan when accounting for the fact that only a portion of
quarks/antiquarks come from the denser and thus thermalized region in the
collision.
