3,302 research outputs found
SU(3)_LxU(1)_N Model for Right-Handed Neutrino Neutral Currents
A model based on the \mbox{SU(3)}_L\otimes \mbox{U(1)}_N gauge group, in
which neutrinos have right-handed neutral currents is considered. We argue that
in order to have a result consistent with low-energy one, the right-handed
neutrino component must be treated as correction instead of an equivalent spin
state.Comment: 6 pages, Latex, no figures, Accepted for publication in Phys. Rev.
Fixed points and vacuum energy of dynamically broken gauge theories
We show that if a gauge theory with dynamical symmetry breaking has
non-trivial fixed points, they will correspond to extrema of the vacuum energy.
This relationship provides a different method to determine fixed points.Comment: 17 pages, uuencoded latex file, 3 figures, uses epsf and epsfig.
Submitted to Mod. Phys. Lett.
KK-Masses in Dipole Deformed Field Theories
We reconsider aspects of non-commutative dipole deformations of field
theories. Among our findings there are hints to new phases with spontaneous
breaking of translation invariance (stripe phases), similar to what happens in
Moyal-deformed field theories. Furthermore, using zeta-function regularization,
we calculate quantum corrections to KK-state masses. The corrections coming
from non-planar diagrams show interesting but non-universal behaviour.
Depending on the type of interaction the corrections can make the KK-states
very heavy but also very light or even tachyonic. Finally we point out that the
dipole deformation of QED is not renormalizable!Comment: 21 pages, 5 figures, uses axodraw.sty, JHEP3.cls; v2:revised version
with minor change
DYNAMICAL SOLUTION OF A MODEL WITHOUT ENERGY BARRIERS
In this note we study the dynamics of a model recently introduced by one of
us, that displays glassy phenomena in absence of energy barriers. Using an
adiabatic hypothesis we derive an equation for the evolution of the energy as a
function of time that describes extremely well the glassy behaviour observed in
Monte Carlo simulations.Comment: 11 pages, LaTeX, 3 uuencoded figure
Supersymmetric One-family Model without Higgsinos
The Higgs potential and the mass spectrum of the N=1 supersymmetric extension
of a recently proposed one-family model based on the local gauge group , which is a subgroup of the electroweak-strong
unification group , is analyzed. In this model the slepton multiplets play
the role of the Higgs scalars and no Higgsinos are needed, with the consequence
that the sneutrino, the selectron and six other sleptons play the role of the
Goldstone bosons. We show how the problem is successfully addressed in
the context of this model which also predicts the existence of a light CP-odd
scalar.Comment: REVTeX 4, 10 pages. Included discussions about constraints coming
from the rho-parameter and from Muon (g-2). References added. Version to
appear in Phys. Rev.
An improved formulation of the relativistic hydrodynamics equations in 2D Cartesian coordinates
A number of astrophysical scenarios possess and preserve an overall
cylindrical symmetry also when undergoing a catastrophic and nonlinear
evolution. Exploiting such a symmetry, these processes can be studied through
numerical-relativity simulations at smaller computational costs and at
considerably larger spatial resolutions. We here present a new
flux-conservative formulation of the relativistic hydrodynamics equations in
cylindrical coordinates. By rearranging those terms in the equations which are
the sources of the largest numerical errors, the new formulation yields a
global truncation error which is one or more orders of magnitude smaller than
those of alternative and commonly used formulations. We illustrate this through
a series of numerical tests involving the evolution of oscillating spherical
and rotating stars, as well as shock-tube tests.Comment: 19 pages, 9 figure
A neutral-pH aqueous redox flow battery based on sustainable organic electrolytes
Aqueous organic redox flow batteries (AORFBs) have gained increasing attention for large-scale storage due to the advantages of decoupled energy and power, safe and sustainable chemistry, and tunability of the redox-active species. Here, we report the development of a neutral-pH AORFB assembled with a highly water-soluble ferrocene 1,1-disulfonic disodium salt (DSâFc) and two viologen derivatives, 1,1â-bis(3-sulfonatopropyl)-viologen (BSPâVi) and Bis(3-trimethylammonium)propyl viologen tetrachloride (BTMAPâVi). Synthesized electrolytes showed excellent redox potential, good diffusion coefficient, and a good transfer rate constant. In particular, BSPâVi has a more negative redox potential (-0.4 V) than BTMAPâVi (â0.3 V) and faster kinetics; therefore, it was selected to be assembled in an AORFB as anolyte, coupled with DSâFc as catholyte.The resulting AORFB based on BTMAPâVi/DSâFc and BSPâVi/DSâFc redox couple had a high cell voltage (1.2 V and 1.3 V, respectively) and theoretical energy density (13 WhLâ1 and 14 WhLâ1 respectively) and was able to sustain 70 charge-discharge cycles with energy efficiency as high as 97 %
WhiskyMHD: a new numerical code for general relativistic magnetohydrodynamics
The accurate modelling of astrophysical scenarios involving compact objects
and magnetic fields, such as the collapse of rotating magnetized stars to black
holes or the phenomenology of gamma-ray bursts, requires the solution of the
Einstein equations together with those of general-relativistic
magnetohydrodynamics. We present a new numerical code developed to solve the
full set of general-relativistic magnetohydrodynamics equations in a dynamical
and arbitrary spacetime with high-resolution shock-capturing techniques on
domains with adaptive mesh refinements. After a discussion of the equations
solved and of the techniques employed, we present a series of testbeds carried
out to validate the code and assess its accuracy. Such tests range from the
solution of relativistic Riemann problems in flat spacetime, over to the
stationary accretion onto a Schwarzschild black hole and up to the evolution of
oscillating magnetized stars in equilibrium and constructed as consistent
solutions of the coupled Einstein-Maxwell equations.Comment: minor changes to match the published versio
Lepton masses in a supersymmetric 3-3-1 model
We consider the mass generation for both charginos and neutralinos in a 3-3-1
supersymmetric model. We show that R-parity breaking interactions leave the
electron and one of the neutrinos massless at the tree level. However the same
interactions induce masses for these particles at the 1-loop level. Unlike the
similar situation in the MSSM the masses of the neutralinos are related to the
masses of the charginos.Comment: RevTex, 11 pages incluing 2 .eps figures. Extended published versio
Neutrino masses and the scalar sector of a B-L extension of the standard model
We consider an electroweak model based on the gauge symmetry SU(2)_L X
U(1)_Y' X U(1)_B-L which has right-handed neutrinos with different exotic B-L
quantum numbers. Because of this particular feature we are able to write Yukawa
terms, and right-handed neutrino mass terms, with scalar fields that can
develop vacuum expectation values belonging to different energy scales. We make
a detailed study of the scalar and the Yukawa neutrino sectors to show that
this model is compatible with the observed solar and atmospheric neutrino mass
scales and the tribimaximal mixing matrix.We also show that there are dark
matter candidates if a Z_2 symmetry is included.Comment: 23 pages, 2 tables, version to be published in Phys. Rev.
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