Probing Majorana neutrinos in rare K and D, D_s, B, B_c meson decays

TL;DR

This paper investigates lepton number violating decays of various mesons mediated by Majorana neutrinos, exploring their potential to reveal neutrino properties and constraints in high-energy experiments.

Contribution

It analyzes meson decay processes induced by Majorana neutrinos across a wide mass range, highlighting scenarios where observable signals could be detected in current or future experiments.

Findings

Branching ratios are generally very small.

Certain meson decays could have detectable rates for neutrino masses between pion and B_c mesons.

Experiments like LHCb and future super flavor-factories could set bounds on neutrino mixing parameters.

Abstract

We study lepton number violating decays of charged K, D, D_s, B and B_c mesons of the form M^+\to {M'}^-\ell^+\ell^+, induced by the existence of Majorana neutrinos. These processes provide information complementary to neutrinoless double nuclear beta decays, and are sensitive to neutrino masses and lepton mixing. We explore neutrino mass ranges m_N from below 1 eV to several hundred GeV. We find that in many cases the branching ratios are prohibitively small, however in the intermediate range m_\pi < m_N < m_{B_c}, in specific channels and for specific neutrino masses, the branching ratios can be at the reach of high luminosity experiments like those at the LHC-b and future Super flavor-factories, and can provide bounds on the lepton mixing parameters.