MiniBooNE anomaly, the decay Ds+ → μ+νμ and heavy sterile neutrino

It has been recently suggested that the anomalous excess of low-energy electronlike events observed by the MiniBooNE experiment could be explained by the radiative decay of a heavy sterile neutrino nu(h) of the mass around 500 MeV with a muonic mixing strength in the range vertical bar U-mu h vertical bar(2) similar or equal to (1-4) x 10(-3). If such nu(h) exists its admixtures in the decay D-s(+) -> mu(+)nu(mu) would result in the decay D-s(+) -> mu(+)nu(h) with the branching fraction Br(D-s(+) -> mu(+)nu(h)) similar or equal to (1.2-5.5) x 10(-4), which is in the experimentally accessible range. Interestingly, the existence of the D-s(+) -> mu(+)nu(h) decay at this level may also explain why the currently measured decay rate of D-s(+) -> mu(+)nu(h) is slightly higher than the predicted one. This enhances motivation for a search for this decay mode and makes it interesting and complementary to neutrino experiments probing sterile-active neutrino mixing. Our estimates show that the sensitive search could be performed with the analysis of existing data, e. g. from the CLEO-c or another analogous experiment. The discrepancy between the measurements and theoretical description of the decay D-s(+) -> tau(+)nu(tau) is also briefly discussed.