Electromagnetic backgrounds in neutrino-produced trimuon events

We discuss the electromagnetic production of ${\mu }^{+}{\mu }^{-}$ pairs in neutrino-induced reactions. The cross section for ${\nu }_{\mu }+N\to {\mu }^{-}+{\mu }^{-}+{\mu }^{+}+X$ is calculated, using a quark-parton model for the photon-hadron interaction, and is ∼0.3×${10}^{-4\mathrm{}}$ of the normal inclusive cross section for ${\nu }_{\mu }+N\to {\mu }^{-}+X$. The precise value depends upon the neutrino spectrum and experimental cuts. We present several distributions which exhibit characteristic features expected from this electromagnetic process. Corresponding reactions involving $e^{+}{e}^{-}$ pairs are also studied because such events should be seen rather easily in bubble-chamber experiments. We also give some results for antineutrino-induced interactions leading to ${\mu }^{+}{\mu }^{+}{\mu }^{-}$ events.