Electromagnetic dipole moment and time reversal invariance violating interactions of high energy short-lived particles in bent and straight crystals

Abstract

A particle, which moves in a crystal experiences weak interactions with electrons and nuclei along with electromagnetic interaction. Measuring the polarization vector and the angular distribution of charged and neutral particles scattered by axes (planes) of an unbent (straight) crystal enables to obtain restrictions for the electromagnetic dipole moments value and for magnitudes of constants describing T-odd ($CP$-odd) interactions beyond the standard model. Spin precession of channeled particles in bent crystals at the LHC gives a unique possibility for measurement of constants determining T-odd ($CP$-odd) violating interactions of short-lived baryons and $\ensuremath{\tau}$-leptons with electrons and nuclei (nucleons), similarly to the possibility of measuring particles' electric and magnetic moments. Methods to separate P-odd spin rotation from the MDM-caused and T-odd spin rotations are discussed.