Investigation of like-sign dimuon production in neutrino and antineutrino reactions

Abstract 290 events of the type ν Fe→ μ − μ − X and 53 events from the reaction ν Fe→μ + μ + X with E ν >30 GeV and muon momenta p μ >6.5GeV/ c have been observed in the CDHS detector. After subtracting the background from charged-current processes with one π or K meson of the hadronic shower decaying into μ − ν (or μ + μ) , we obtain for neutrinos a rate of prompt like- sign dimuon production of (3.4±1.8)×10 −5 relative to the rate of charged-current events with the same cuts, or (4.1 ± 2.2)% relative to the prompt μ − μ + rate, and for antineutrinos the corresponding relative rates (4.3±2.3)×10 −5 and (4.2 ± 2.3)%. A possible explanation for the events is charm pair production at a level of 10 −3 relative to all charged-current reactions.