M. Kubantsev

Observation of tau neutrino interactions

Abstract The DONUT experiment has analyzed 203 neutrino interactions recorded in nuclear emulsion targets. A decay search has found evidence of four tau neutrino interactions with an estimated background of 0.34 events. This number is consistent with the Standard Model expectation.The DONUT experiment has analyzed 203 neutrino interactions recorded in nuclear emulsion targets. A decay search has found evidence of four tau neutrino interactions with an estimated background of 0.34 events. This number is consistent with the Standard Model expectation.

A new upper limit for the tau-neutrino magnetic moment

Abstract Using a neutrino beam in which a ντ component was identified for the first time, the ντ magnetic moment was measured based on a search for an anomalous increase in the number of neutrino–electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit on μντ of 3.9×10−7μB.Using a prompt neutrino beam in which a nu_tau component was identified for the first time, the nu_tau magnetic moment was measured based on a search for an anomalous increase in the number of neutrino-electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.

Intranuclear Cascade in the Interactions of Neutrinos with Neon Nuclei

A method is developed for separating νN interactions from interactions involving an intranuclear cascade in νNe scattering at a mean neutrino energy of 145 GeV. The fraction of events featuring a cascade is evaluated by using a sample of νNe charged-current interactions. It is found that the multiplicity of charged particles in the forward direction takes the same value for events with and without a cascade for 4<W2<550 GeV2. In the backward direction, cascade events have the charge multiplicity higher than the multiplicity for cascade-free events by 2.36 units. It is found that particles with momenta less than 2 GeV/c make a dominant contribution to the rescattering process. A depletion of the fastest particles for W2<50 GeV2 is observed, in accord with the formation-time concept.