58 research outputs found
Flavour Model for Dirac Neutrinos: Type I and Inverse Seesaw
We propose two different seesaw models namely, type I and inverse seesaw to
realise light Dirac neutrinos within the framework of discrete flavour
symmetry. The additional fields and their transformations under the flavour
symmetries are chosen in such a way that naturally predicts the hierarchies of
different elements of the seesaw mass matrices in these two types of seesaw
mechanisms. For generic choices of flavon alignments, both the models predict
normal hierarchical light neutrino masses with the atmospheric mixing angle in
the lower octant. Apart from predicting interesting correlations between
different neutrino parameters as well as between neutrino and model parameters,
the model also predicts the leptonic Dirac CP phase to lie in a specific range
- to . While the type I seesaw model predicts smaller values of
absolute neutrino mass, the inverse seesaw predictions for the absolute
neutrino masses can saturate the cosmological upper bound on sum of absolute
neutrino masses for certain choices of model parameters.Comment: 19 pages, 08 figures; matches published versio
Flavored Leptogenesis and Neutrino Mass with Symmetry
We propose a minimal flavor symmetric model, assisted by symmetry, which can naturally takes care of the appropriate lepton mixing
and neutrino masses via Type-I seesaw. It turns out that the framework,
originated due to a specific flavor structure, favors the normal hierarchy of
light neutrinos and simultaneously narrows down the range of Dirac CP violating
phase. It predicts an interesting correlation between the atmospheric mixing
angle and the Dirac CP phase too. While the flavor structure indicates an exact
degeneracy of the right handed neutrino masses, renormalization group running
of the same from a high scale is shown to make it quasi-degenerate and a
successful flavor leptogenesis takes place within the allowed parameter space
obtained from neutrino phenomenology.Comment: 35 pages, 8 figure
Phenomenology of the flavor symmetric scoto-seesaw model with dark matter and TM mixing
We propose a hybrid scoto-seesaw model based on the non-Abelian
discrete flavor symmetry. Light neutrino masses come from the tree-level type-I
seesaw mechanism and from the one-loop scotogenic contribution accommodating
viable dark matter candidates responsible for observed relic abundance of dark
matter (DM). Respectively, both these contributions restore the atmospheric and
solar neutrino mass scales. With only one right-handed neutrino, the model
features specific predictions with the normal ordering of light neutrino
masses, the lightest neutrino being massless, and only one relevant CP Majorana
phase. The flavor symmetric setup helps us to realize the TM mixing scheme
with concrete correlations and constraints on the mixing angles and associated
CP phases. The framework predicts the atmospheric mixing angle to be in the
upper octant with specific ranges and the Dirac CP phase is restricted within the range
radian. The Majorana phase is also tightly constrained with a
range of and radian, which is otherwise unconstrained
from neutrino oscillations. Strict predictions on the Majorana phases also
yield an accurate prediction for the effective mass parameter for neutrinoless
double beta within the range of meV. The model offers a rich
phenomenology regarding DM relic density and direct search constraints, and the
fermionic DM scenario has been discussed in detail, estimating its possible
connection with the neutrino sector. As an example of the model studies at
colliders, the SM Higgs in the diphoton decay channel is examined. The model
predicts strictly vanishing , decays
and testable signals by MEG-II and SINDRUM/Mu3e experiments for the and decays, respectively.Comment: 42 pages, 16 figure
Optical Anisotropy of Electronic Excitations in Elliptical Quantum Dots
The authors report that anisotropic confining potentials in laterally-coupled
semiconductor quantum dots (QDs) have large impacts in optical transitions and
energies of inter-shell collective electronic excitations. The observed
anisotropies are revealed by inelastic light scattering as a function of the
in-plane direction of light polarization and can be finely controlled by
modifying the geometrical shape of the QDs. These experiments show that the
tuning of the QD confinement potential offers a powerful method to manipulate
electronic states and far-infrared inter-shell optical transitions in quantum
dots.Comment: 8 pages, 4 figure
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