1,346 research outputs found
Hidden Interactions of Sterile Neutrinos As a Probe For New Physics
Recent results from neutrino experiments show evidence for light sterile
neutrinos which do not have any Standard Model interactions. In this work we
study the hidden interaction of sterile neutrinos with an "MeV scale" gauge
boson (the HI model) with mass and leptonic coupling .
By performing an analysis on the HI model using the data of the MINOS
neutrino experiment we find that the values above are excluded
by more than C.L., where is the Fermi constant and is the
field strength of the HI model. Using this model we can also probe other
new physics scenarios. We find that the region allowed by the
discrepancy is entirely ruled out for MeV. Finally, the
secret interaction of sterile neutrinos has been to solve a conflict between
the sterile neutrinos and cosmology. It is shown here that such an interaction
is excluded by MINOS for . This exclusion,
however, does depend on the value of .Comment: 11 pages, 2 figures, Improved version with new figures and further
details. Accepted in PR
Revising Limits on Neutrino-Majoron Couplings
Any theory that have a global spontaneously broken symmetry will imply the
existence of very light neutral bosons or massless bosons (sometimes called
Majorons). For most of these models we have neutrino-Majoron couplings, that
appear as additional branching ratios in decays of mesons and leptons. Here we
present an updated limits on the couplings between the electron, muon and tau
neutrinos and Majorons. For such we analyze the possible effects of Majoron
emission in both meson and lepton decays. In the latter we also include an
analysis of the muon decay spectrum. Our results are
, and
at 90 % C. L., where .Comment: 12 pages, 5 figure
Atmospheric neutrinos: LMA oscillations, Ue3 induced interference and CP-violation
We consider oscillations of the low energy (sub-GeV sample) atmospheric
neutrinos in the three neutrino context. We present the semi-analytic study of
the neutrino evolution and calculate characteristics of the e-like events
(total number, energy spectra and zenith angle distributions) in the presence
of oscillations. At low energies there are three different contributions to the
number of events: the LMA contribution (from electron-neutrino oscillations
driven by the solar oscillation parameters), the Ue3-contribution proportional
to s13**2, and the Ue3 - induced interference of the two amplitudes driven by
the solar oscillation parameters. The interference term is sensitive to the
CP-violation phase. We describe in details properties of these contributions.
We find that the LMA, the interference and Ue3 contributions can reach 5 - 6%,
2 - 3% and 1 - 2 % correspondingly. An existence of the significant (> 3 - 5 %)
excess of the e-like events in the sub-GeV sample and the absence of the excess
in the multi-GeV range testifies for deviation of the 2-3 mixing from maximum.
We consider a possibility to measure the deviation as well as the CP- violation
phase in future atmospheric neutrino studies.Comment: 30 pages, RevTeX4.0, 11 figures; improved figure
Constraints on neutrino decay lifetime using long-baseline charged and neutral current data
We investigate the status of a scenario involving oscillations and decay for
charged and neutral current data from the MINOS and T2K experiments. We first
present an analysis of charged current neutrino and anti-neutrino data from
MINOS in the framework of oscillation with decay and obtain a best fit for
non-zero decay parameter . The MINOS charged and neutral current data
analysis results in the best fit for ~eV, and zero decay parameter, which
corresponds to the limit for standard oscillations. Our combined MINOS and T2K
analysis reports a constraint at the 90\% confidence level for the neutrino
decay lifetime ~s/eV. This is the best limit
based only on accelerator produced neutrinos
A Short Travel for Neutrinos in Large Extra Dimensions
Neutrino oscillations successfully explain the flavor transitions observed in
neutrinos produced in natural sources like the center of the sun and the earth
atmosphere, and also from man-made sources like reactors and accelerators.
These oscillations are driven by two mass-squared differences, solar and
atmospheric, at the sub-eV scale. However, longstanding anomalies at
short-baselines might imply the existence of new oscillation frequencies at the
eV-scale and the possibility of this sterile state(s) to mix with the three
active neutrinos. One of the many future neutrino programs that are expected to
provide a final word on this issue is the Short-Baseline Neutrino Program (SBN)
at FERMILAB. In this letter, we consider a specific model of Large Extra
Dimensions (LED) which provides interesting signatures of oscillation of extra
sterile states. We started re-creating sensitivity analyses for sterile
neutrinos in the 3+1 scenario, previously done by the SBN collaboration, by
simulating neutrino events in the three SBN detectors from both muon neutrino
disappearance and electron neutrino appearance. Then, we implemented neutrino
oscillations as predicted in the LED model and also we have performed
sensitivity analysis to the LED parameters. Finally, we studied the SBN power
of discriminating between the two models, the 3+1 and the LED. We have found
that SBN is sensitive to the oscillations predicted in the LED model and have
the potential to constrain the LED parameter space better than any other
oscillation experiment, for . In case SBN observes a
departure from the three active neutrino framework, it also has the power of
discriminating between sterile oscillations predicted in the 3+1 framework and
the LED ones.Comment: 21 pages, 6 figures, 2 table
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