Creation of transversely polarized high-energy electrons and positrons in crystals

Abstract

It is shown that when high-energy y quanta pass through a crystal at small angles to the crystallo- graphic planes (axes) a new phenomenon arises: creation of transversely polarized electrons and positrons by unpolarized y quanta. Estimates based on the theory developed in this paper for this phenomenon show that it can be used to obtain transversely polarized electrons and positrons with degree of polarization 50-90% and with energies of hundreds and thousands GeV in the case of incidence of the y quanta on atomic planes, and starting with an energy of several tens of GeV in the case of incidence on atomic axes. Concrete calculations are made of the polarization, number, and angular distributions of positrons produced by 350-GeV y quanta incident on the (1 10) family of planes of a tungsten plate of thickness 3 X 10 cm. The features of the manifestation of the described phenomenon in bent crystals are analyzed.