435 research outputs found
Improved Limit on theta_{13} and Implications for Neutrino Masses in Neutrino-less Double Beta Decay and Cosmology
We analyze the impact of a measurement, or of an improved bound, on
theta_{13} for the determination of the effective neutrino mass in
neutrino-less double beta decay and cosmology. In particular, we discuss how an
improved limit on (or a specific value of) theta_{13} can influence the
determination of the neutrino mass spectrum via neutrino-less double beta
decay. We also discuss the interplay with improved cosmological neutrino mass
searches.Comment: 22 pages, 5 figures. Minor corrections, matches version in PR
Curtailing the Dark Side in Non-Standard Neutrino Interactions
In presence of non-standard neutrino interactions the neutrino flavor
evolution equation is affected by a degeneracy which leads to the so-called
LMA-Dark solution. It requires a solar mixing angle in the second octant and
implies an ambiguity in the neutrino mass ordering. Non-oscillation experiments
are required to break this degeneracy. We perform a combined analysis of data
from oscillation experiments with the neutrino scattering experiments CHARM and
NuTeV. We find that the degeneracy can be lifted if the non-standard neutrino
interactions take place with down quarks, but it remains for up quarks.
However, CHARM and NuTeV constraints apply only if the new interactions take
place through mediators not much lighter than the electroweak scale. For light
mediators we consider the possibility to resolve the degeneracy by using data
from future coherent neutrino-nucleus scattering experiments. We find that, for
an experiment using a stopped-pion neutrino source, the LMA-Dark degeneracy
will either be resolved, or the presence of new interactions in the neutrino
sector will be established with high significance.Comment: 33 pages, 9 figures. Minor modifications. Version accepted for
publication in JHE
Neutrino CP violating parameters from nontrivial quark-lepton correlation: a S3xGUT model
We investigate the prediction on the lepton phases in theories with a non
trivial correlation between quark (CKM) and lepton (PMNS) mixing matrices. We
show that the actual evidence, under the only assumption that the correlation
matrix product of and has a zero in the entry , gives
us a prediction for the three CP-violating invariants , , and . A
better determination of the lepton mixing angles will give a strong prediction
of the CP-violating invariants in the lepton sector. These will be tested in
the next generation experiments. To clarify how our prediction works, we show
how a model based on a Grand Unified Theory and the permutation flavor symmetry
predicts .Comment: 7 pages, 3 figures. V2: new figure adde
A GEANT-based study of atmospheric neutrino oscillation parameters at INO
We have studied the dependence of the allowed space of the atmospheric
neutrino oscillation parameters on the time of exposure for a magnetized Iron
CALorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). We
have performed a Monte Carlo simulation for a 50 kTon ICAL detector generating
events by the neutrino generator NUANCE and simulating the detector response by
GEANT. A chi-square analysis for the ratio of the up-going and down-going
neutrinos as a function of is performed and the allowed regions at 90%
and 99% CL are displayed. These results are found to be better than the current
experimental results of MINOS and Super-K. The possibilities of further
improvement have also been discussed.Comment: 8 pages, 13 figures, a new figure added, version accepted in IJMP
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