Search for the flavor-changing neutral current decay Do→μ+μ- the HERA-B detector

We report on a search for the flavor-changing neutral current decay D-0 --> mu(+)mu(-) using 50 x 10(6) events recorded with a dimuon trigger in interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find no evidence for such decays and set a 90% confidence level upper limit on the branching fraction beta(D-0 --> mu(+)mu(-)) < 2.0 x 10(-6). (C) 2004 Elsevier B.V. All rights reserved.