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

W. Sobków

doi:10.1140/epjc/s10052-014-2997-x

EPJ

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2023 Impact factor 4.2

Particles and Fields

Open Access

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

W. Sobków^*

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 $$V+A$$ interaction in addition to the standard $$V-A$$ interaction. We show that the angle–energy distribution of Dirac muon neutrinos ( $\nu _{\mu }$ ’) is sensitive to the interference terms between the standard $$V-A$$ coupling of left-chirality $\nu _{\mu }$ and exotic $$V+A$$ coupling of right-chirality one, which are proportional to the transverse components of $\nu _{\mu }$ spin polarization. The interferences do not vanish in the limit of massless $\nu _{\mu }$ 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 $\nu _{\mu }$ 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 $\nu _{\mu }$ limit, there are physical effects connected with the mixture of left- and right-handed helicity components in a spin $$1/2$$ quantum state, when the exotic interaction $$V+A$$ is admitted, contrary to the electron observables, where all the possible interferences vanish.