Quantum kinetic theory of spin polarization of massive quarks in perturbative QCD: Leading log

We present the quantum kinetic equation for the spin polarization of massive quarks in leading-log order of perturbative QCD, which describes time evolution of the spin density matrix in momentum space of a massive quark interacting with a background QCD plasma. We find that the time evolution operator of the spin density matrix or the quantum kinetic collision terms are universally of order αₛ²log(1/αₛ) in terms of the QCD coupling constant αₛ=g²/(4π). Our quantum kinetic equation is valid for an arbitrary quark mass mmD~gT, where mD is the Debye mass, and can be used to study relaxation dynamics of spin polarization of massive quarks in the perturbative QCD regime.