144,034 research outputs found
Lagrangian approach to local symmetries and self-dual model in gauge invariant formulation
Taking the St\"uckelberg Lagrangian associated with the abelian self-dual
model of P.K. Townsend et al as a starting point, we embed this mixed first-
and second-class system into a pure first-class system by following
systematically the generalized Hamiltonian approach of Batalin, Fradkin and
Tyutin. The resulting Lagrangian possesses an extended gauge invariance and
provides a non-trivial example for a general Lagrangian approach to unravelling
the full set of local symmetries of a Lagrangian.Comment: LaTeX, 15 page
Generalized BFT Formalism of Electroweak Theory in the Unitary Gauge
We systematically embed the SU(2)U(1) Higgs model in the unitary
gauge into a fully gauge-invariant theory by following the generalized BFT
formalism. We also suggest a novel path to get a first-class Lagrangian
directly from the original second-class one using the BFT fields.Comment: 14 pages, Latex, no figure
Phase Transitions in the Early Universe
The physics of the 20th Century is governed by two pillars, Einstein's
relativity principle and the quantum principle. At the beginning of the 21st
Century, it becomes clear that there exist the smallest units of matter, such
as electrons, neutrinos, and quarks; their behaviors are described by the
Standard Model.
It was believed that the temperature of the early Universe was once 300 GeV,
or higher, at , and then going through the electroweak phase
transition. But the mass phase transition happens in the purely imaginary
temperature. Later on, its temperature was 150 MeV at ,
and then going through the "QCD cosmological phase transition". We attempt to
use the Standard Model, a completely dimensionless theory apart from the
negative "ignition" term, to conclude that the EW or mass phase transition {\it
does not exist}.
On the front of QCD cosmological phase transition, the intriguing question
about the latent heat (energy) is discussed and its role is speculated.Comment: 24 pages, 1 figur
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 7Li+208Pb System at Near-Coulomb-Barrier Energies using the Folding Potential
Simultaneous analyses previously made for elastic scattering and
fusion cross section data for the Li+Pb system is extended to the
Li+Pb system at near-Coulomb-barrier energies based on the
extended optical model approach, in which the polarization potential is
decomposed into direct reaction (DR) and fusion parts. Use is made of the
double folding potential as a bare potential. It is found that the experimental
elastic scattering and fusion data are well reproduced without introducing any
normalization factor for the double folding potential and that both the DR and
fusion parts of the polarization potential determined from the
analyses satisfy separately the dispersion relation. Further, we find that the
real part of the fusion portion of the polarization potential is attractive
while that of the DR part is repulsive except at energies far below the Coulomb
barrier energy. A comparison is made of the present results with those obtained
from the Continuum Discretized Coupled Channel (CDCC) calculations and a
previous study based on the conventional optical model with a double folding
potential. We also compare the present results for the Li+Pb system
with the analysis previously made for the Li+Pb system.Comment: 7 figures, submitted to PR
Magnetoresistance devices Progress report
Investigating galvanomagnetic effects in developing higher magnetoresistance devices for low voltage high current switche
The effects of surface finish and grain size on the strength of sintered silicon carbide
The effects of surface treatment and microstructure, especially abnormal grain growth, on the strength of sintered SiC were studied. The surfaces of sintered SiC were treated with 400, 800 and 1200 grit diamond wheels. Grain growth was induced by increasing the sintering times at 2050 C. The beta to alpha transformation occurred during the sintering of beta-phase starting materials and was often accompanied by abnormal grain growth. The overall strength distributions were established using Weibull statistics. The strength of the sintered SiC is limited by extrinsic surface flaws in normal-sintered specimens. The finer the surface finish and grain size, the higher the strength. But the strength of abnormal sintering specimens is limited by the abnormally grown large tabular grains. The Weibull modulus increases with decreasing grain size and decreasing grit size for grinding
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