12,578 research outputs found
Effects and influences on neutrino oscillations due to a thin density layer perturbation added to a matter density profile
In this paper, we show the effects on the transition probabilities for
neutrino oscillations due to a thin constant density layer perturbation added
to an arbitrary matter density profile. In the case of two neutrino flavors, we
calculate the effects both analytically and numerically, whereas in the case of
three neutrino flavors, we perform the studies purely numerically. As an
realistic example we consider the effects of the Earth's atmosphere when added
to the Earth's matter density profile on the neutrino oscillation transition
probabilities for atmospheric neutrinos.Comment: 9 pages, 6 figures, LaTeX. Final version to be published in Phys.
Lett.
Extrinsic CPT Violation in Neutrino Oscillations
In this talk, we investigate extrinsic CPT violation in neutrino oscillations
in matter with three flavors. Note that extrinsic CPT violation is different
from intrinsic CPT violation. Extrinsic CPT violation is one way of quantifying
matter effects, whereas intrinsic CPT violation would mean that the CPT
invariance theorem is not valid. We present analytical formulas for the
extrinsic CPT probability differences and discuss their implications for
long-baseline experiments and neutrino factory setups.Comment: 4 pages, 1 figure, aipproc LaTeX. Talk presented at the 5th
International Workshop on Neutrino Factories & Superbeams (NuFact'03),
Columbia University, New York, USA, June 5-11, 2003. To be published in the
Proceedings of NuFact'03 (AIP Conference Proceedings
T-violating effects in three flavor neutrino oscillations in matter
In this talk, we consider the interplay of fundamental and matter-induced
T-violating effects in neutrino oscillations in matter. We present a simple
approximative analytical formula for the T-violating probability asymmetry for
three flavor neutrino oscillations in matter with an arbitrary density profile.
We also discuss some implications of the obtained results. Since there are no
T-violating effects in two flavor neutrino case (in the limit of vanshing
or , the three flavor neutrino oscillations
reduces to the two flavor ones), the T-violating probability asymmetry can, in
principle, provide a way to measure and .Comment: 5 pages, 4 figures, JHEP LaTeX. Talk presented at the International
Europhysics Conference on High Energy Physics (EPS HEP 2001), Budapest,
Hungary, July 12-18, 2001. In collaboration with: Evgeny Akhmedov, Patrick
Huber, and Manfred Lindne
Status of non-standard neutrino interactions
The phenomenon of neutrino oscillations has been established as the leading
mechanism behind neutrino flavor transitions, providing solid experimental
evidence that neutrinos are massive and lepton flavors are mixed. Here we
review sub-leading effects in neutrino flavor transitions known as non-standard
neutrino interactions, which is currently the most explored description for
effects beyond the standard paradigm of neutrino oscillations. In particular,
we report on the phenomenology of non-standard neutrino interactions and their
experimental and phenomenological bounds as well as future sensitivity and
discovery reach.Comment: 51 pages, 11 figures. Final version published in Rep. Prog. Phy
Running of Fermion Observables in Non-Supersymmetric SO(10) Models
We investigate the complete renormalization group running of fermion
observables in two different realistic non-supersymmetric models based on the
gauge group with intermediate symmetry breaking for both
normal and inverted neutrino mass orderings. Contrary to results of previous
works, we find that the model with the more minimal Yukawa sector of the
Lagrangian fails to reproduce the measured values of observables at the
electroweak scale, whereas the model with the more extended Yukawa sector can
do so if the neutrino masses have normal ordering. The difficulty in finding
acceptable fits to measured data is a result of the added complexity from the
effect of an intermediate symmetry breaking as well as tension in the value of
the leptonic mixing angle .Comment: 15 pages, 3 figures, 4 tables. Final version published in JHE
Fits to Non-Supersymmetric SO(10) Models with Type I and II Seesaw Mechanisms Using Renormalization Group Evolution
We consider numerical fits to non-supersymmetric -based
models in which neutrino mass is generated by the type-I or type-II seesaw
mechanism or a combination of both. The fits are performed with a sophisticated
top-down procedure, taking into account the renormalization group equations of
the gauge and Yukawa couplings, integrating out relevant degrees of freedom at
their corresponding mass scales, and using recent data for the Standard Model
observables. We find acceptable fits for normal neutrino mass ordering only and
with neutrino mass generated by either type-I seesaw only or a combination of
types I and II seesaw in which type-I seesaw is dominant. Furthermore, we find
predictions from the best fit regarding the small neutrino masses, the
effective neutrinoless double beta decay mass, and the leptonic CP-violating
phase. Finally, we show that the fits are rather insensitive to the chosen
value of the unification scale.Comment: 22 pages, 3 figures, 3 tables. Final version published in JHE
Neutrino flux ratios at neutrino telescopes: The role of uncertainties of neutrino mixing parameters and applications to neutrino decay
In this paper, we derive simple and general perturbative formulas for the
flavor flux ratios that
could be measured at neutrino telescopes. We discuss in detail the role of the
uncertainties of the neutrino mixing parameters showing that they have to be
seriously taken into account in any realistic discussion about flavor
measurements at neutrino telescopes. In addition, we analyze the impact of such
uncertainties in telling the standard neutrino oscillation framework from
scenarios involving, e.g., neutrino decay and we find that the ratio
is the most sensitive one to "new physics" effects beyond the Standard Model.
We also compute the more realistic muon-to-shower ratio for a particular
configuration of the IceCube experiment, observing that using this experimental
quantity a clear separation between standard and non-standard neutrino physics
cannot be obtained.Comment: 21 pages, 7 figures, LaTeX. Final version published in Phys. Rev.
Decaying Dark Matter in Halos of Primordial Black Holes
We investigate photon signatures of general decaying dark-matter particles in
halos of primordial black holes. We derive the halo-profile density and the
total decay rate for these combined dark-matter scenarios. For the case of
axion-like particles of masses below keV, we find strong
bounds on the decay constant which are several orders of magnitude stronger
than the strongest existing bounds, for all halo masses above solar masses. Using future X-ray measurements, it will be possible
to push these bounds on such combined dark-matter scenarios even further.Comment: 5 pages, 3 figures; v2: revised in order to match published versio
Effective Neutrino Mixing and Oscillations in Dense Matter
We investigate the effective case of two-flavor neutrino oscillations in
infinitely dense matter by using a perturbative approach. We begin by briefly
summarizing the conditions for the three-flavor neutrino oscillation
probabilities to take on the same form as the corresponding two-flavor
probabilities. Then, we proceed with the infinitely dense matter calculations.
Finally, we study the validity of the approximation of infinitely dense matter
when the effective matter potential is large, but not infinite, this is done by
using both analytic and numeric methods.Comment: 12 pages, 4 figures, Elsevier LaTeX, Final version to be published in
Phys. Lett.
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