Polarization through the elastic scattering in magnetic field

Abstract

There exists conceptual possibility to obtain the polarized beams of particles through their elastic scattering in magnetic field. Here such possibility is discussed with the use of classical spin models for, both, the cases of charged and neutral magneton. In the charged particle case the fundamental possibility to observe the effect stems from results of Novosibirsk experiment carried out in 1984. Within the proposed schematic design the polarization process lies in more rapid getting out from the trajectory of those particles which have “wrong” spin directions. For the charged particle the BMT and Frenkel models predict opposite Langevin-type polarizations and for the neutral particles the results obtained from the both are identical being consistent with the previous studies. Parameter [Formula: see text] (Sokolov–Ternov polarization time for electrons) is shown to emerge within the classical theory. The effect of noncomplete equilibrium polarization degree cannot be obtained in such model experiment since the kinetic process of the spin-flip transitions is left beyond the scheme considered. At that time the noninertial nature of motion entails in asymmetry between dependencies of spin–spin radiation rate on two horizontal spin components. This purely classical property is analyzed in the context of so-called “circular Unruh effect.”