Probing the Majorana neutrinos and their CP violation in decays of charged scalar mesons $\pi, K, D, D_s, B, B_c$

TL;DR

This paper explores how charged meson decays can reveal the Majorana nature of neutrinos and potential CP violation, especially within the neutrino minimal standard model, offering insights into fundamental particle properties.

Contribution

It proposes new methods to distinguish Dirac from Majorana neutrinos using meson decays and highlights the potential to observe CP violation in scenarios with nearly degenerate Majorana neutrinos.

Findings

Decays of charged mesons can indicate Majorana neutrinos.

CP violation may be detectable in specific neutrino mass scenarios.

The approach aligns with the neutrino minimal standard model (νMSM).

Abstract

Some of the outstanding questions of particle physics today concern the neutrino sector, in particular whether there are more neutrinos than those already known and whether they are Dirac or Majorana particles.There are different ways to explore these issues. In this article we describe neutrino-mediated decays of charged pseudoscalar mesons such as $\pi^{\pm}$, $K^{\pm}$ and $B^{\pm}$, in scenarios where extra neutrinos are heavy and can be on their mass shell. We discuss semileptonic and leptonic decays of such kinds. We investigate possible ways of using these decays in order to distinguish between the Dirac and Majorana character of neutrinos. Further, we argue that there are significant possibilities of detecting CP violation in such decays when there are at least two almost degenerate Majorana neutrinos involved. This latter type of scenario fits well into the known neutrino minimal standard model ($\nu$MSM) which could simultaneously explain the Dark Matter and Baryon Asymmetry of the Universe.