218 research outputs found
Zero minors of the neutrino mass matrix
We examine the possibility that a certain class of neutrino mass matrices,
namely those with two independent vanishing minors in the flavor basis,
regardless of being invertible or not, is sufficient to describe current data.
We compute generic formulae for the ratios of the neutrino masses and for the
Majorana phases. We find that seven textures with two vanishing minors can
accommodate the experimental data. We present an estimate of the mass matrix
for these patterns. All the possible textures can be dynamically generated
through the seesaw mechanism augmented with a discrete Abelian symmetry.Comment: latex, 22 pages, 7 figures, 2 tables, accepted version to appear in
PR
One vanishing minor in the neutrino mass matrix
We study a specific texture of the neutrino mass matrix, namely the models
with one subdeterminant equal to zero. We carry out a complete
phenomenological analysis with all possible relevant correlations. Every
pattern of the six possible ones is found able to accommodate the experimental
data, with three cases allowing also for non-invertible mass matrices. We
present symmetry realizations for all the models.Comment: 21 pages, 11 figures, 4 table
General Modified Friedmann Equations in Rainbow Flat Universe, by Thermodynamics
We investigate the derivation of Friedmann equations in Rainbow gravity
following Jacobson thermodynamic approach. We do not restrict the rainbow
functions to be constant as is customarily used, and show that the first law of
thermodynamics with a corresponding `classical' proportionality between entropy
and surface area, supplemented eventually by a `quantum' logarithmic
correction, are not in general sufficient to obtain the equations in flat FRW
metrics.Comment: 7 pages, to appear in EPJ
QCD Sum Rules and the Determination of Leading Twist Non-Singlet Operator Matrix Elements
We use QCD sum rules to determine directly the leading-twist non-singlet
operator matrix elements based on calculations of three-point correlator
functions in configuration space. We find a different result from that obtained
by integrating the structure functions' expressions obtained by Belyaev and
Ioffe based on calculations of four-point correlators in momentum space. The
origin of this discrepancy remains unclear.Comment: 9 pages, 5 figure
On Inflation and Variation of the Strong Coupling Constant
Variation of constants in the very early universe can generate inflation. We
consider a scenario where the strong coupling constant was changing in time and
where the gluon condensate underwent a phase transition ending the inflation.Comment: 12 pages, 1 figure, accepted for publication in International Journal
of Modern Physics
Neutrino Mixing and Leptogenesis in Symmetry
We study the consequences of the -symmetry behind the --
universality in neutrino mass matrix. We then implement this symmetry in the
type-I seesaw mechanism and show how it can accommodate all sorts of lepton
mass hierarchies and generate enough lepton asymmetry to interpret the observed
baryon asymmetry in the universe. We also show how a specific form of a
high-scale perturbation is kept when translated via the seesaw into the low
scale domain, where it can accommodate the neutrino mixing data. We finally
present a realization of the high scale perturbed texture through addition of
matter and extra exact symmetries.Comment: 29 pages, 1 figure, 3 tables. Complete re-analysis. Version to appear
in PR
Textures of Neutrino Mass Matrix from -flavor Symmetry
We study a texture of neutrino mass matrix characterized by two constraints
consisting of one equality and another antiequality between two elements
corresponding to two pairs of the matrix entries. Amidst such textures, we
limit our study to three patterns which were realizable assuming an
-symmetry within type II-seesaw scenario. Three such cases were found and
studied: I ( \& ), II ( \& ) and III (
\& ). We specify the role of non-physical phases in the
definition of the textures under study which were tested against experimental
constraints, and were found to accommodate data with both hierarchies allowed.
However, switching off the non-physical phases allows only for inverted
hierarchy, except for the texture III which allows also, albeit for a very
narrow parameter space region, for normal ordering. We present a complete
phenomenological analysis of these three textures and justify analytically the
resulting correlations. We detail the effect of the non-physical phases is
diluting/deforming several correlations, which otherwise would have been
``clear". Finally, we give theoretical realizations within seesaw type II
scenarios for such textures.Comment: 40 pages, pdflatex, 6 tables and 12 figures. arXiv admin note: text
overlap with arXiv:2208.1034
The U(1) symmetry of the non-tribimaximal pattern in the degenerate mass spectrum case of the neutrino mass matrix
On account of the new neutrino oscillation data signalling a non-zero value
for the smallest mixing angle (), we present an explicit realization
of the underlying U(1) symmetry characterizing the maximal atmospheric mixing
angle () pattern with two degenerate masses but now with
generic values of . We study the effects of the form invariance with
respect to U(1), and/or , subgroups, on the Yukawa couplings and the
mass terms. Later on, we specify to its experimental best fit value
(), and impose the symmetry in an entire model which includes
charged leptons, and many Higgs doublets or standard model singlet heavy
scalars, to show that it can make room for the charged lepton mass hierarchies.
In addition, we show for the non-tribimaximal value of within
type-I seesaw mechanism enhanced with flavor symmetry that neutrino mass
hierarchies can be generated. Furthermore, lepton/baryogenesis can be
interpreted via type-II seesaw mechanism within a setup meeting the flavor
U(1)-symmetry.Comment: latex, 1 table, 20 pages. Typos are corrected, shortened version to
appear in Phys. Rev.
The One-zero Textures of Majorana Neutrino Mass Matrix and Current Experimental Tests
We carry out a complete and systematic study of all the possible one-zero
textures for the neutrino mass matrix in light of the recent neutrino
oscillation data which hint to a relatively large non-vanishing value for the
smallest mixing angle (). We find that all the six possible one-zero
textures are able to accommodate the experimental data, with five cases
allowing also for non-invertible mass matrices. We present symmetry
realizations for all the one-zero singular and non-singular patterns in type-I
and type-II seesaw mechanism schemes.Comment: 35 pages, 14 figures, 8 tables, title change, complete re-analysis
with the new updated data, version to appear in PRD. arXiv admin note:
substantial text overlap with arXiv:0909.266
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