Right-handed Neutrinos in $\nu_{\mu} + e \to \nu_{\mu} + e$ Elastic Scattering

Abstract

In this paper a scenario admitting the participation of the exotic right-handed scalar $S_{R}$ coupling in addition to the standard left-handed $(V, A)_{L}$ couplings in the low energy neutrino-electron scattering is considered. The main goal is to show how the presence of the right-handed neutrinos in the $(\nu e)$ scattering changes the laboratory differential cross section in relation to the Standard Model prediction. We consider the $(\nu e)$ process at the level of the four-fermion point interaction. Muon-neutrinos are assumed to be massive and to be polarized Dirac fermions. In the laboratory differential cross section the new interference term between the the standard $V_{L}$ coupling of the left-handed neutrino and exotic $S_{R}$ coupling of the right-handed neutrino appears which does not vanish in the limit of massless neutrino. This new contribution, including the information about the transverse neutrino polarization, generates the azimuthal assymetry in the angular distribution of the recoil electrons. This regularity would be the proof of the presence of R-handed neutrinos in the $\nu e$ scattering.