Eur. Phys. J. C (2014) 74: 2997
https://doi.org/10.1140/epjc/s10052-014-2997-x

Regular Article - Theoretical Physics

Right-handed chirality of muon neutrinos in polarized muon decay at rest

Institute of Theoretical Physics, University of Wrocław, Pl. M. Born 9, 50-204 , Wrocław, Poland

^* e-mail: wieslaw.sobkow@ift.uni.wroc.pl

Received: 12 March 2014
Accepted: 23 July 2014
Published online: 12 August 2014

Abstract

In this paper, we analyze the polarized muon decay at rest admitting the non-standard interaction in addition to the standard interaction. We show that the angle–energy distribution of Dirac muon neutrinos (’) is sensitive to the interference terms between the standard coupling of left-chirality and exotic coupling of right-chirality one, which are proportional to the transverse components of spin polarization. The interferences do not vanish in the limit of massless and include the relative phases to test the CP violation. It allows one to calculate a neutrino flux for an assumed configuration of detector in the case of standard model prediction, and the upper limits on the neutrino flux for the left–right mixture. It is also demonstrated that the effects of neutrino mass and mixing are tiny corrections and can be omitted. The most important conclusion is that even in the massless limit, there are physical effects connected with the mixture of left- and right-handed helicity components in a spin quantum state, when the exotic interaction is admitted, contrary to the electron observables, where all the possible interferences vanish.