1,426 research outputs found
Left-Right Symmetry and Supersymmetric Unification
The existence of an SU(3) X SU(2)_L X SU(2)_R X U(1) gauge symmetry with g_L
= g_R at the TeV energy scale is shown to be consistent with supersymmetric
SO(10) grand unification at around 1O^{16} GeV if certain new particles are
assumed. The additional imposition of a discrete Z_2 symmetry leads to a
generalized definition of R parity as well as highly suppressed Majorana
neutrino masses. Another model based on SO(10) X SO(10) is also discussed.Comment: 11 pages, 2 figures not included, UCRHEP-T124, Apr 199
Implications of LEP Results for SO(10) Grandunification with Two Intermediate Stages
We consider the breaking of the grand unification group to the
standard model gauge group through several chains containing two intermediate
stages. Using the values of the gauge coupling constants at scale derived
from recent LEP data, we determine the range of their intermediate and
unification scales. In particular, we identify those chains that permit new
gauge structure at relatively low energy .Comment: (LATEX, 9 pages + 3 pages of figures not included) OITS-48
Power Spectrum of the density of cold atomic gas in the Galaxy towards Cas A and Cygnus A
We have obtained the power spectral description of the density and opacity
fluctuations of the cold HI gas in the Galaxy towards Cas A, and Cygnus A. We
have employed a method of deconvolution, based on CLEAN, to estimate the true
power spectrum of optical depth of cold HI gas from the observed distribution,
taking into account the finite extent of the background source and the
incomplete sampling of optical depth over the extent of the source. We
investigate the nature of the underlying spectrum of density fluctuations in
the cold HI gas which would be consistent with that of the observed HI optical
depth fluctuations. These power spectra for the Perseus arm towards Cas A, and
for the Outer arm towards Cygnus A have a slope of 2.75 +/- 0.25 (3sigma
error). The slope in the case of the Local arm towards Cygnus A is 2.5, and is
significantly shallower in comparison. The linear scales probed here range from
0.01 to 3 pc. We discuss the implications of our results, the non-Kolmogorov
nature of the spectrum, and the observed HI opacity variations on small
transverse scales.Comment: 19 pages, 7 figures, to appear in the Astrophysical Journal of
November 1, 200
Leptogenesis with Left-Right domain walls
The presence of domain walls separating regions of unbroken and
is shown to provide necessary conditions for leptogenesis which
converts later to the observed Baryon aymmetry. The strength of lepton number
violation is related to the majorana neutrino mass and hence related to current
bounds on light neutrino masses. Thus the observed neutrino masses and the
Baryon asymmetry can be used to constrain the scale of Left-Right symmetry
breaking.Comment: References added, To appear in Praman
SU(3) Decomposition of Two-Body B Decay Amplitudes
We present the complete flavor SU(3) decomposition of decay amplitudes for
decays of the triplet (B^+_u, B^0_d, B^0_s) of B mesons nonleptonically into
two pseudoscalar mesons. This analysis holds for arbitrarily broken SU(3) and
can be used to generate amplitude relations when physical arguments permit one
to neglect or relate any of the reduced amplitudes.Comment: 31 pages, revtex, no figure
Fermion masses and mixings in gauge theories
The recent evidence for neutrino oscillations stimulate us to discuss again
the problem of fermion masses and mixings in gauge theories. In the standard
model, several forms for quark mass matrices are equivalent. They become
ansatze within most extensions of the standard model, where also relations
between quark and lepton sectors may hold. In a seesaw framework, these
relations can constrain the scale of heavy neutrino mass, which is often
related to the scale of intermediate or unification gauge symmetry. As a
consequence, two main scenarios arise. Hierarchies of masses and mixings may be
explained by broken horizontal symmetries.Comment: 25 pages, RevTex, no figures. Few misprints corrected and two
references adde
A novel case of MSTO1 gene related congenital muscular dystrophy with progressive neurological involvement
Recessive mutations in the MSTO1 gene, encoding for a mitochondrial distribution and morphology regulator, have been recently described in a very limited number of patients with multisystem involvement, mostly characterized by myopathy or dystrophy, cerebellar ataxia, pigmentary retinopathy and raised creatine kinase levels. Here we report an additional patient with recessive MSTO1-related muscular dystrophy (MSTO1-RD), and clinical and radiological evidence of progressive cerebellar involvement. Whole-exome sequencing identified two novel MSTO1 missense variants, c.766C > T (p. (Arg256Trp) and c.1435C > T (p. (Pro479Ser), predicted as damaging by in silico tools. We also report a distinct pattern of selective involvement on muscle MRI in MSTO1-RD. This case confirms a consistent MSTO1-related neuromuscular phenotype and in addition suggests a progressive neurological component at least in some patients, in keeping with the mitochondrial role of the defective protein
Muon Anomalous and Gauged Models
In this paper we study contribution to of the muon anomalous
magnetic dipole moment in gauged models. Here are
the lepton numbers. We find that there are three classes of models which can
produce a large value of to account for possible discrepancy between the
experimental data and the Standard Model prediction. The three classes are: a)
Models with an exact . In these models, is
massless. The new gauge interaction coupling is constrained
to be . b) Models with broken
and the breaking scale is not related to electroweak
symmetry breaking scale. The gauge boson is massive. The allowed range of
the coupling and the mass are constrained, but mass can be large; And
c) The is broken and the breaking scale is related to the
electroweak scale. In this case the mass is constrained to be
GeV. We find that there are interesting experimental signatures in
in these models.Comment: 13 pages, 9 figure
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