51 research outputs found
Two experiments for the price of one? -- The role of the second oscillation maximum in long baseline neutrino experiments
We investigate the quantitative impact that data from the second oscillation
maximum has on the performance of wide band beam neutrino oscillation
experiments. We present results for the physics sensitivities to standard three
flavor oscillation, as well as results for the sensitivity to non-standard
interactions. The quantitative study is performed using an experimental setup
similar to the Fermilab to DUSEL Long Baseline Neutrino Experiment (LBNE). We
find that, with the single exception of sensitivity to the mass hierarchy, the
second maximum plays only a marginal role due to the experimental difficulties
to obtain a statistically significant and sufficiently background-free event
sample at low energies. This conclusion is valid for both water Cherenkov and
liquid argon detectors. Moreover, we confirm that non-standard neutrino
interactions are very hard to distinguish experimentally from standard
three-flavor effects and can lead to a considerable loss of sensitivity to
\theta_{13}, the mass hierarchy and CP violation.Comment: RevTex 4.1, 23 pages, 10 figures; v2: Typos corrected, very minor
clarifications; matches published version; v3: Fixed a typo in the first
equation in sec. III
MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations
The recently observed event excess in MiniBooNE anti-neutrino data is in
agreement with the LSND evidence for electron anti-neutrino appearance. We
propose an explanation of these data in terms of a (3+1) scheme with a sterile
neutrino including non-standard neutrino interactions (NSI) at neutrino
production and detection. The interference between oscillations and NSI
provides a source for CP violation which we use to reconcile different results
from neutrino and anti-neutrino data. Our best fit results imply NSI at the
level of a few percent relative to the standard weak interaction, in agreement
with current bounds. We compare the quality of the NSI fit to the one obtained
within the (3+1) and (3+2) pure oscillation frameworks. We also briefly comment
on using NSI (in an effective two-flavour framework) to address a possible
difference in neutrino and anti-neutrino results from the MINOS experiment.Comment: 28 pages, 9 figures, discussion improved, new appendix added,
conclusions unchange
Searching for sterile neutrinos in ice
Oscillation interpretation of the results from the LSND, MiniBooNE and some
other experiments requires existence of sterile neutrino with mass eV
and mixing with the active neutrinos . It has
been realized some time ago that existence of such a neutrino affects
significantly the fluxes of atmospheric neutrinos in the TeV range which can be
tested by the IceCube Neutrino Observatory. In view of the first IceCube data
release we have revisited the oscillations of high energy atmospheric neutrinos
in the presence of one sterile neutrino. Properties of the oscillation
probabilities are studied in details for various mixing schemes both
analytically and numerically. The energy spectra and angular distributions of
the events have been computed for the simplest mass, and
mixing schemes and confronted with the IceCube data. An
illustrative statistical analysis of the present data shows that in the
mass mixing case the sterile neutrinos with parameters required by
LSND/MiniBooNE can be excluded at about level. The
mixing scheme, however, can not be ruled out with currently available IceCube
data.Comment: 41 pages, 16 figures. Accepted for publication in JHEP. Minor changes
from the previous versio
Measurement of the antineutrino neutral-current elastic differential cross section
arXiv:1309.7257v1 [hep-ex
Minimal models with light sterile neutrinos
We study the constraints imposed by neutrino oscillation experiments on the
minimal extensions of the Standard Model (SM) with gauge singlet fermions
("right-handed neutrinos"), that can account for neutrino masses. We consider
the most general coupling to SM fields of the new fields, in particular those
that break lepton number and we do not assume any a priori hierarchy in the
mass parameters. We proceed to analyze these models starting from the lowest
level of complexity, defined by the number of extra fermionic degrees of
freedom. The simplest choice that has enough free parameters in principle (i.e.
two mass differences and two angles) to explain the confirmed solar and
atmospheric oscillations corresponds to . This minimal choice is shown
to be excluded by data. The next-to-minimal choice corresponds to . We
perform a systematic study of the full parameter space in the limit of
degenerate Majorana masses by requiring that at least two neutrino mass
differences correspond to those established by solar and atmospheric
oscillations. We identify several types of spectra that can fit long-baseline
reactor and accelerator neutrino oscillation data, but fail in explaining solar
and/or atmospheric data. The only two solutions that survive are the expected
seesaw and quasi-Dirac regions, for which we set lower and upper bounds
respectively on the Majorana mass scale. Solar data from neutral current
measurements provide essential information to constrain the quasi-Dirac region.
The possibility to accommodate the LSND/MiniBoone and reactor anomalies, and
the implications for neutrinoless double-beta decay and tritium beta decay are
briefly discussed.Comment: 32 pages, 15 figures. Misprints and a small error corrected,
references added. Conclusions unchange
Very special relativity as relativity of dark matter: the Elko connection
In the very special relativity (VSR) proposal by Cohen and Glashow, it was
pointed out that invariance under HOM(2) is both necessary and sufficient to
explain the null result of the Michelson-Morely experiment. It is the quantum
field theoretic demand of locality, or the requirement of P, T, CP, or CT
invariance, that makes invariance under the Lorentz group a necessity.
Originally it was conjectured that VSR operates at the Planck scale; we propose
that the natural arena for VSR is at energies similar to the standard model,
but in the dark sector. To this end we provide an ab initio spinor
representation invariant under the SIM(2) avatar of VSR and construct a mass
dimension one fermionic quantum field of spin one half. This field turns out to
be a very close sibling of Elko and it exhibits the same striking property of
intrinsic darkness with respect to the standard model fields. In the new
construct, the tension between Elko and Lorentz symmetries is fully resolved.
We thus entertain the possibility that the symmetries underlying the standard
model matter and gauge fields are those of Lorentz, while the event space
underlying the dark matter and the dark gauge fields supports the algebraic
structure underlying VSR.Comment: 19 pages. Section 5 is new. Published version (modulo a footnote, and
a corrected typo
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