Relaxation of spin-polarized low-density electron gas

We derive the relaxation time of the total spin polarization for a low–density spin–polarized gas of fermions (electrons). This calculation is based on previously obtained collision operator in kinetic equation. This collision operator takes into consideration the spin component of interacting particles. As a side result we obtained the optical theorem, corresponding to the collision operator. Wherein we used the global symmetries in the mutual scattering amplitudes of two electrons. The result obtained is viable even in the case of relatively cold low–density spin–polarized plasma. The final result is obtained under assumption of small summary spin–polarization of fermions.