Majorana Neutrinos in Muon Decay

Abstract

The normal muon decay ${\mu }^{+}\to e^{+}{\nu }_e\overline{{\nu }_{\mu }}$ is studied as a tool to discriminate between the Dirac and Majorana type neutrinos. For the purpose to do this, we propose a new parameterization in place of the Michel parameters for the energy spectrum of $e^{+}$. The ${\chi }^2$-fitting is used by noticing different energy spectra between the Dirac and Majorana neutrino cases. We assume the interaction Hamiltonian which consists of the $V-A$ and $V+A$ charged currents.

Comments: 9 pages. Talk given at NNR05 workshop on Neutrino Nuclear Responses in Double Beta Decays and Low-energy Astro-neutrinos, CAST and SPring-8, Japan, 2-4 December 2005