99 research outputs found
Probing the Neutrino Mass Hierarchy with Super-Kamiokande
We show that for recently discovered large values of theta(13), a superbeam
with an average neutrino energy of ~ 5 GeV, such as those being proposed at
CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino
mass hierarchy at 5 sigma in less than two years irrespective of the true
hierarchy and CP phase. The measurement relies on the near resonant matter
effect in the numu to nue oscillation channel, and can be done counting the
total number of appearance events with just a neutrino beam.Comment: 16 pages, 7 pdf figures, 2 tables. Format changed and text extended.
Four new pdf figures added. Dependency of the result on 1-3 mixing angle
discussed. Conclusions unchanged. Accepted in JHE
Precision on leptonic mixing parameters at future neutrino oscillation experiments
We perform a comparison of the different future neutrino oscillation
experiments based on the achievable precision in the determination of the
fundamental parameters theta_{13} and the CP phase, delta, assuming that
theta_{13} is in the range indicated by the recent Daya Bay measurement. We
study the non-trivial dependence of the error on delta on its true value. When
matter effects are small, the largest error is found at the points where CP
violation is maximal, and the smallest at the CP conserving points. The
situation is different when matter effects are sizable. As a result of this
effect, the comparison of the physics reach of different experiments on the
basis of the CP discovery potential, as usually done, can be misleading. We
have compared various proposed super-beam, beta-beam and neutrino factory
setups on the basis of the relative precision of theta_{13} and the error on
delta. Neutrino factories, both high-energy or low-energy, outperform
alternative beam technologies. An ultimate precision on theta_{13} below 3% and
an error on delta of < 7^{\circ} at 1 sigma (1 d.o.f.) can be obtained at a
neutrino factory.Comment: Minor changes, matches version accepted in JHEP. 30 pages, 9 figure
Potential of optimized NOvA for large theta(13) & combined performance with a LArTPC & T2K
NOvA experiment has reoptimized its event selection criteria in light of the
recently measured moderately large value of theta(13). We study the improvement
in the sensitivity to the neutrino mass hierarchy and to leptonic CP violation
due to these new features. For favourable values of deltacp, NOvA sensitivity
to mass hierarchy and leptonic CP violation is increased by 20%. Addition of 5
years of neutrino data from T2K to NOvA more than doubles the range of deltacp
for which the leptonic CP violation can be discovered, compared to stand alone
NOvA. But for unfavourable values of deltacp, the combination of NOvA and T2K
are not enough to provide even a 90% C.L. hint of hierarchy discovery.
Therefore, we further explore the improvement in the hierarchy and CP violation
sensitivities due to the addition of a 10 kt liquid argon detector placed close
to NOvA site. The capabilities of such a detector are equivalent to those of
NOvA in all respects. We find that combined data from 10 kt liquid argon
detector (3 years of nu + 3 years of nubar run), NOvA (6 years of nu + 6 years
of nubar run) and T2K (5 years of nu run) can give a close to 2 sigma hint of
hierarchy discovery for all values of deltacp. With this combined data, we can
achieve CP violation discovery at 95% C.L. for roughly 60% values of deltacp.Comment: 22 pages, 24 pdf figures, 5 tables. In the appendix, new results are
presented with conservative choices of central values of oscillation
parameters. New references are added. Accepted in JHE
Constraining Non-Standard Interactions of the Neutrino with Borexino
We use the Borexino 153.6 ton.year data to place constraints on non-standard
neutrino-electron interactions, taking into account the uncertainty in the 7Be
solar neutrino flux, and backgrounds due to 85Kr and 210Bi beta-decay. We find
that the bounds are comparable to existing bounds from all other experiments.
Further improvement can be expected in Phase II of Borexino due to the
reduction in the 85Kr background.Comment: 21 pages, 16 pdf figures, 2 tables. Analysis updated including the
uncertainty in sin^2\theta_{23}. Accepted in JHE
Mass hierarchy discrimination with atmospheric neutrinos in large volume ice/water Cherenkov detectors
Large mass ice/water Cherenkov experiments, optimized to detect low energy
(1-20 GeV) atmospheric neutrinos, have the potential to discriminate between
normal and inverted neutrino mass hierarchies. The sensitivity depends on
several model and detector parameters, such as the neutrino flux profile and
normalization, the Earth density profile, the oscillation parameter
uncertainties, and the detector effective mass and resolution. A proper
evaluation of the mass hierarchy discrimination power requires a robust
statistical approach. In this work, the Toy Monte Carlo, based on an extended
unbinned likelihood ratio test statistic, was used. The effect of each model
and detector parameter, as well as the required detector exposure, was then
studied. While uncertainties on the Earth density and atmospheric neutrino flux
profiles were found to have a minor impact on the mass hierarchy
discrimination, the flux normalization, as well as some of the oscillation
parameter (\Delta m^2_{31}, \theta_{13}, \theta_{23}, and \delta_{CP})
uncertainties and correlations resulted critical. Finally, the minimum required
detector exposure, the optimization of the low energy threshold, and the
detector resolutions were also investigated.Comment: 23 pages, 16 figure
Enhancing sensitivity to neutrino parameters at INO combining muon and hadron information
Running of oscillation parameters in matter with flavor-diagonal non-standard interactions of the neutrino
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