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

290 events of the type νFe→μ^?μ^?X and 53 events from the reaction $\text{ν}\text{Fe→μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{+}}\text{X with}\text{E}{}_{\mathrm{\nu }}\text{>30}\text{GeV}$ 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 $\text{μ}{}^{\mathrm{?}}\text{ν}\text{(or μ}{}^{\mathrm{+}}\text{μ)}$, 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.