Search for neutral, long-lived particles decaying into two muons in pp̄ collisions at s=1.96TeV

We present a search for a neutral particle, pair produced in pp̄ collisions at s=1.96TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses 380pb-1 of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4×10-11s, we exclude values greater than 0.14 pb (95 C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events. © 2006 The American Physical Society.