137 research outputs found
Self Consistent Expansion In The Presence Of Electroweak Interactions
In the conventional approach to the expansion, electroweak
interactions are switched off and large QCD is treated in isolation. We
study the self-consistency of taking the large limit in the presence of
electroweak interaction. If the electroweak coupling constants are held
constant, the large counting rules are violated by processes involving
internal photon or weak boson lines. Anomaly cancellations, however, fix the
ratio of electric charges of different fermions. This allows a self-consistent
way to scale down the electronic charge in the large limit and hence
restoring the validity of the large counting rules.Comment: 9 pages in REVTeX, no figure
CP Violation in Fermion Pair Decays of Neutral Boson Particles
We study CP violation in fermion pair decays of neutral boson particles with
spin 0 or 1. We study a new asymmetry to measure CP violation in decays and discuss the possibility of measuring it
experimentally. For the spin-1 particles case, we study CP violation in the
decays of to octet baryon pairs. We show that these decays can
be used to put stringent constraints on the electric dipole moments of
, and .Comment: 14p, OZ-93/22, UM-93/89, OITS 51
Semileptonic decays
We study the four-body exclusive semileptonic baryonic decays of
() in the standard
model. We find that their decay branching ratios are about , respectively. In particular, the electron mode is
close to the corresponding CLEO's upper limit of , while all
results are about one or two orders of magnitude larger than the previous
estimated values for the inclusive modes of . Clearly, both B-factories of Belle and BaBar should be able to observe
these exclusive four-body modes.Comment: 10 pages, 3 figures, published versio
Axion-photon Couplings in Invisible Axion Models
We reexamine the axion-photon couplings in various invisible axion models
motivated by the recent proposal of using optical interferometry at the ASST
facility in the SSCL to search for axion. We illustrate that the assignment of
charges for the fermion fields plays an important role in
determining the couplings. Several simple non-minimal invisible axion models
with suppressed and enhanced axion-photon couplings are constructed,
respectively. We also discuss the implications of possible new experiments to
detect solar axions by conversion to -rays in a static magnetic apparatus
tracking the sun.Comment: 14 pages, LaTeX fil
Hypermagnetic Baryogenesis
We study a new scenario for baryogenesis due to the spontaneous breaking of
the invariance through the interaction between a baryon current and a
hypermagnetic helicity. The hypermagnetic helicity (Chern-Simons number) of
provides a violation background for the generation of baryons
via sphaleron processes, which protects these baryons from the sphaleron
wash-out effect in thermal equilibrium. It is shown that if the present
amplitude of the resultant magnetic fields are sufficiently large, for a wide
range mass scale (from TeV to the Planck scale), the observational magnitude of
the baryon asymmetry of the Universe can be realized.Comment: 8 pages, no figure, accepted in Phys. Lett.
Electric charge quantization and the muon anomalous magnetic moment
We investigate some proposals to solve the electric charge quantization
puzzle, which simultaneously explain the recent measured deviation on the muon
anomalous magnetic moment. For this we assess extensions of the Electro-Weak
Standard Model spanning modifications on the scalar sector only. It is
interesting to verify that one can have modest extensions which easily account
for the solution for both problems.Comment: 20 pages, 1 figures, needs macro axodraw.st
Can Close the Supersymmetric Higgs Production Window?
We show that the present limit from CLEO on the inclusive decay provides strong constraints on the parameters of the charged Higgs
sector in two-Higgs-Doublet-Models. Only a slight improvement in the
experimental bound will exclude the region in the Supersymmetric Higgs
parameter space which is inaccessible to collider searches.Comment: 8 pages plus 3 figures (available by request), latex,
ANL-HEP-PR-92-110. Substantial revision to text, results unchange
Generalized second law of thermodynamics in f(T) gravity
We investigate the validity of the generalized second law (GSL) of
gravitational thermodynamics in the framework of f(T) modified teleparallel
gravity. We consider a spatially flat FRW universe containing only the
pressureless matter. The boundary of the universe is assumed to be enclosed by
the Hubble horizon. For two viable f(T) models containing
and , we first
calculate the effective equation of state and deceleration parameters. Then, we
investigate the null and strong energy conditions and conclude that a sudden
future singularity appears in both models. Furthermore, using a cosmographic
analysis we check the viability of two models. Finally, we examine the validity
of the GSL and find that for both models it is satisfied from the early times
to the present epoch. But in the future, the GSL is violated for the special
ranges of the torsion scalar T.Comment: 16 pages, 10 figures, accepted by JCAP 201
Analysis of B_s->\phi \ell^+ \ell^- decay with new physics effects
The rare B_s-> \phi \ell^+ \ell^- decay is investigated by using the most
general model independent effective Hamiltonian for . The
calculated Br(B_s \rar \phi \mu^+ \mu^-) = 1.92 \times 10^{-6} is in
consistent with the experimental upper bound. The dependencies of the branching
ratios and polarization asymmetries of leptons and combined lepton-antilepton
asymmetries on the new Wilson coefficients are presented. The analysis shows
that the branching ratios and the lepton polarization asymmetries are very
sensitive to the scalar and tensor type interactions. The results obtained in
this work will be very useful in searching new physics beyond the standard
model.Comment: 28 pages, 14 figure
Longitudinal polarization asymmetry of leptons in the pure leptonic B decays
Longitudinal lepton polarization asymmetry in B_q -> l l (q = d, s$ and l =
e, mu, tau) decays is investigated. The analysis is done in a general manner by
using the effective operators approach. It is shown that the longitudinal
lepton polarization asymmetry would provide a direct search for the scalar and
pseudoscalar type interactions, which are induced in all variants of
Higgs-doublet models.Comment: 7 page
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