Decay of polarized muon at rest as a source of polarized neutrino beam

TL;DR

This paper explores the theoretical use of polarized muon decay at rest as a source of transversely polarized electron antineutrinos to test for new physics beyond the standard model, focusing on CP violation and Lorentz structure.

Contribution

It introduces a model-independent analysis of polarized muon decay as a novel neutrino source for probing non-standard weak interactions.

Findings

Energy and angular distributions depend on transverse polarization components.

Analysis is consistent with current limits on non-standard couplings.

Results assume particles are massless in the decay process.

Abstract

In this paper, we indicate the theoretical possibility of using the decay of polarized muons at rest as a source of the transversely polarized electron antineutrino beam. Such a beam can be used to probe new effects beyond standard model. We mean here new tests concerning CP violation, Lorentz structure and chirality structure of the charged current weak interactions. The main goal is to show how the energy and angular distribution of the electron antineutrinos in the muon rest frame depends on the transverse components of the antineutrino beam polarization. Our analysis is model-independent and consistent with the current upper limits on the non-standard couplings. The results are presented in a limit of infinitesimally small mass for all particles produced in the decay.