22,632 research outputs found
Global-String and Vortex Superfluids in a Supersymmetric Scenario
The main goal of this work is to investigate the possibility of finding the
supersymmetric version of the U(1)-global string model which behaves as a
vortex-superfluid. To describe the superfluid phase, we introduce a
Lorentz-symmetry breaking background that, in an approach based on
supersymmetry, leads to a discussion on the relation between the violation of
Lorentz symmetry and explicit soft supersymmetry breakings. We also study the
relation between the string configuration and the vortex-superfluid phase. In
the framework we settle down in terms of superspace and superfields, we
actually establish a duality between the vortex degrees of freedom and the
component fields of the Kalb-Ramond superfield. We make also considerations
about the fermionic excitations that may appear in connection with the vortex
formation.Comment: 9 pages. This version presented the relation between Lorentz symmetry
violation by the background and the appearance of terms that explicitly break
SUS
Flavour symmetries in a renormalizable SO(10) model
In the context of a renormalizable supersymmetric SO(10) Grand Unified
Theory, we consider the fermion mass matrices generated by the Yukawa couplings
to a representation
of scalars. We perform a complete investigation of the possibilities of
imposing flavour symmetries in this scenario; the purpose is to reduce the
number of Yukawa coupling constants in order to identify potentially predictive
models. We have found that there are only 14 inequivalent cases of Yukawa
coupling matrices, out of which 13 cases are generated by symmetries,
with suitable , and one case is generated by a symmetry. A
numerical analysis of the 14 cases reveals that only two of them---dubbed A and
B in the present paper---allow good fits to the experimentally known fermion
masses and mixings.Comment: 36 pages, no figures, revised fits using newer data, added fit for
case A, added references, new appendices concerning the SO(10) scalar
potential and inequalities for the vacuum expectation values, conclusions
unchanged; some minor changes, matches published versio
Scotogenic model for co-bimaximal mixing
We present a scotogenic model, i.e. a one-loop neutrino mass model with dark
right-handed neutrino gauge singlets and one inert dark scalar gauge doublet
, which has symmetries that lead to co-bimaximal mixing, i.e. to an
atmospheric mixing angle and to a -violating phase
, while the mixing angle remains arbitrary.
The symmetries consist of softly broken lepton numbers (), a non-standard symmetry, and three symmetries. We
indicate two possibilities for extending the model to the quark sector. Since
the model has, besides , three scalar gauge doublets, we perform a
thorough discussion of its scalar sector. We demonstrate that it can
accommodate a Standard Model-like scalar with mass , with
all the other charged and neutral scalars having much higher masses.Comment: v2 - 23 pages, 5 figures, minor changes requested by refere
Some Comments on BPS systems
We look at simple BPS systems involving more than one field. We discuss the
conditions that have to be imposed on various terms in Lagrangians involving
many fields to produce BPS systems and then look in more detail at the simplest
of such cases. We analyse in detail BPS systems involving 2 interacting
Sine-Gordon like fields, both when one of them has a kink solution and the
second one either a kink or an antikink solution. We take their solitonic
static solutions and use them as initial conditions for their evolution in
Lorentz covariant versions of such models. We send these structures towards
themselves and find that when they interact weakly they can pass through each
other with a phase shift which is related to the strength of their interaction.
When they interact strongly they repel and reflect on each other. We use the
method of a modified gradient flow in order to visualize the solutions in the
space of fields.Comment: 27 pages, 17 figure
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