Search for lepton-number-violating signals in the charm sector

We explore signals of lepton-number-violation in the charm physics sector. We study the four-body |ΔL|=2 decays of the D0 meson, D0→P-π-μ+μ+ (P=π, K) as an alternative evidence of the Majorana nature of neutrinos. We carry out an exploratory study on the potential sensitivity that LHCb experiment could achieve for these |ΔL|=2 processes. We show that for a long term expected integrated luminosity of 300 fb-1, a signal significance of branching ratios of the order O(10-9) might be accessible, allowing to improve the experimental bounds obtained by the E791 experiment. Limits on the parameter space of a heavy sterile neutrino that could be obtained from their experimental search are discussed as well.