22,247 research outputs found
Neutrinoless double beta decay with scalar bilinears
One possible probe to physics beyond the standard model is to look for scalar
bilinears, which couple to two fermions of the standard model. We point out
that the scalar bilinears allow new diagrams contributing to the neutrinoless
double beta decay. The upper bound on the neutrinoless double beta decay
lifetime would then give new constraints on the ratio of the masses of these
scalars to their couplings to the fermions.Comment: 11 pages latex with 3 figure
Neutrino Mass Matrices in Models with Horizontal Symmetries
We have studied the most general neutrino mass matrices in models with SU(2)
and SU(3) horizontal symmetries. Without going into the details of the models
it is possible to write down the effective operators, which predict the
structure of the Majorana neutrino mass matrices. Unlike other extensions of
the standard model, the structure is now independent of the effective Yukawa
couplings and depends entirely on the Higgs which gives mass to the other
fermions. In the case of SU(3) symmetries the lowest dimensional operators are
forbidden requiring a low mass scale for lepton number violation.Comment: 11 pages latex file, a few references added in 2nd versio
Geometric scaling in ultrahigh energy neutrinos and nonlinear perturbative QCD
The ultrahigh energy neutrino cross section is a crucial ingredient in the
calculation of the event rate in high energy neutrino telescopes. Currently
there are several approaches which predict different behaviors for its
magnitude for ultrahigh energies. In this contribution is presented a summary
of current predictions based on the non-linear QCD evolution equations, the
so-called perturbative saturation physics. In particular, predictions are shown
based on the parton saturation approaches and the consequences of geometric
scaling property at high energies are discussed. The scaling property allows an
analytical computation of the neutrino scattering on nucleon/nucleus at high
energies, providing a theoretical parameterization.Comment: 6 pages, one figure. Presented at First Caribbean Symposium on
Nuclear and Astroparticle Physics - STARS2011, La Habana, Cuba, 2011. arXiv
admin note: substantial text overlap with arXiv:1011.2718 by different
author
Effects of New Gravitational Interactions on Neutrinoless Double Beta Decay
It has recently been proposed that violations of Lorentz invariance or
violations of the equivalence principle can be constrained from the
non-observation of neutrinoless double beta decay. We generalize this analysis
to all possible new gravitational interactions and discuss briefly the
constraints for different cases.Comment: 10 page
Inherent properties of binary tetrahedral semiconductors
A new approach utilising the concept of ionic charge theory has been used to
explain the inherent properties such as lattice thermal conductivity and bulk
modulus of 3,5 and 2,6 semiconductors. The lattice thermal conductivity of
these semiconductors exhibit a linear relationship when plotted on a log scale
against the nearest neighbour distance but fall on two straight lines according
to the product of the ionic charge of the compounds. On the basis of this
result a simple relationship of lattice thermal conductivity with bulk modulus
is proposed and used to estimate the bulk modulus of these semiconductors. A
fairly good agreement has been found between the experimantal and calculated
values of these parameters for zinc blende structured solids.Comment: 6 pages, 19 reference
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