Further Observation Of Trimuon Production By Neutrinos And Antineutrinos

We have observed six additional trimuons in a neutrino beam and one trimuon in an antineutrino beam using the new large-angle neutrino detector (NEULAND) at Fermilab. One of the neutrino events has three very high-energy muons. The properties of the new trimuon events together with the earlier events suggest at least two qualitatively different origins for this phenomenon.