6,180 research outputs found
New limits on radiative sterile neutrino decays from a search for single photons in neutrino interactions
It has been recently shown that excess events observed by the LSND and
MiniBooNE neutrino experiments could be interpreted as a signal from the
radiative decay of a heavy sterile neutrino \nu_h produced in \nu_\mu neutral
current-like interactions. If the \nu_h exist, it would be also produced by the
\nu_\mu beam from the CERN SPS in the neutrino beam line shielding. The \nu_h's
would penetrate the shielding and be observed through the decay \nu_h -> \nu
\gamma, followed by the photon conversion into e+e- pair in the active target
of the NOMAD detector. The \nu_h's could be also produced in the iron of the
magnetic spectrometer of the CHORUS detector, located just in front of NOMAD.
Considering these two sources of \nu_h's we set new constraints on \nu_h
properties and exclude part of the LSND/MiniBooNE \nu_h parameter space using
bounds on single photons production in neutrino reactions recently reported by
the NOMAD collaboration. We find that broad bands in the parameter space are
still open for more sensitive searches for the \nu_h in future neutrino
experiments.Comment: 10 pages, 5 figures. Revised version to appear in PLB. Discussion of
dominant NC-like production of \nu_h's adde
Tau neutrino magnetic moments from the Super-Kamiokande and e-scattering data
Combined results on oscillations and -scattering from the Super-Kamiokande and LAMPF experiments, respectively,
limit the Dirac diagonal magnetic moment to . For the scheme with 3 Majorana neutrinos the LAMPF
results allow the limitation of effective magnetic moment to
. The moments in the scheme with
additional Majorana light sterile neutrinos as well as experiments on
stimulated radiative neutrino conversion are also discussed.Comment: 12 pages, To appear in Phys. Lett.
Sterile neutrino decay as a common origin for LSND/MiniBooNe and T2K excess events
We point out that the excess of electron-like neutrino events recently
observed by the T2K collaboration may have a common origin with the similar
excess events previously reported by the LSND and MiniBooNE experiments and
interpreted as a signal from the radiative decays of a sterile neutrino \nu_h
with the mass around 50 MeV produced in muon neutrino neutral current (NC)
interactions. In this work we assumed that the \nu_h can also be produced in
tau neutrino NC reactions.Comment: 5 pages, 5 figures. Revised version accepted by PRD (Rapid Comm.)
after referee's suggestions. Fig.1 added for illustratio
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