Search for heavy Majorana neutrino in lepton number violating decays of D → K π e + e +

Abstract

Using a data sample with an integrated luminosity of 2.93 fb(-1) taken at the center-of-mass energy of 3.773 GeV, we search for the Majorana neutrino (nu(m)) in the lepton number violating decays D -> K pi e(+)e(+). No significant signal is observed, and the upper limits on the branching fraction at the 90% confidence level are set to be B(D degrees -> K-pi(-)e(+)e(+)) < 2.8 x 10(-6) , B(D+ -> K-S(0)pi(-) e(+)e(+)) < 3.3 x 10(-6) and B(D+ -> K-pi(0)e(+)e(+)) < 8.5 x 10(-6). The Majorana neutrino is searched for with different mass assumptions ranging from 0.25 to 1.0 GeV/c(2) in the decays D-0 -> K(-)e(+)nu(m),nu(m) -> pi(-)e(+) and D+ -> K(S)(0)e(+)nu(m),nu(m) -> pi(-)e(+),and the upper limits on the branching fraction at the 90% confidence level are at the level of 10(-7) similar to 10(-6), depending on the mass of the Majorana neutrino. The constraints on the mixing matrix element vertical bar V-e nu m vertical bar(2) are also evaluated.