Trimuon production in \nu N-scattering as a probe of massive neutrinos

TL;DR

This paper investigates a rare lepton-number violating process involving muons and neutrinos to explore the potential presence of Majorana neutrinos, providing new constraints on their masses and effective parameters.

Contribution

It is the first study to analyze u_ N     X process in relation to second-generation Majorana neutrino masses, improving sensitivity estimates.

Findings

The process ratio is enhanced by several orders of magnitude compared to previous models.

Non-observation constrains the effective Majorana neutrino mass to less than 10^4 GeV.

Current bounds are more stringent than earlier direct experimental limits.

Abstract

The lepton-number violating process \nu_\mu N \to \mu^- \mu^+ \mu^+ X is studied for the first time in connection with Majorana neutrino masses of the second generation. The sensitivity for light and heavy Majorana neutrinos is investigated. The ratio with respect to the standard model charged current process is improved by some orders of magnitude if compared to previously discussed Majorana induced \Delta L_{\mu} = 2 processes. Non-observation of this process in previous experiments allows to demand the effective mass to be < m_{\mu \mu} > \ls 10^4 GeV, being more stringent than previously discussed direct bounds, however still unnaturally high. Therefore, in the forseeable future, indirect bounds on effective masses other than m_{ee} will be more stringent.