1,233 research outputs found
Fate of Vector Dominance in the Effective Field Theory
We reveal the full phase structure of the effective field theory for QCD,
based on the hidden local symmetry (HLS) through the one-loop renormalization
group equation including quadratic divergences. We then show that vector
dominance (VD) is not a sacred discipline of the effective field theory but
rather an accidental phenomenon peculiar to three-flavored QCD. In particular,
the chiral symmetry restoration in HLS model takes place in a wide phase
boundary surface, on which the VD is realized nowhere. This suggests that VD
may not be valid for chiral symmetry restoration in hot and/or dense QCD.Comment: 4 pages, 3 figures. One reference added. Minor modification to
shorten the manuscript. This is the version to appear in Physical Review
Letter
Hypercharge and baryon minus lepton number in E6
We study assignments of the hypercharge and baryon minus lepton number for
particles in the grand unification model. It is shown that there are
three assignments of hypercharge and three assignments of baryon minus lepton
number which are consistent with the Standard Model. Their explicit expressions
and detailed properties are given. In particular, we show that the
symmetry in cannot be orthogonal to the symmetry. Based on
these investigations, we propose an alternative SU(5) grand unification model.Comment: 16 pages, JHEP3.cls, To appear in JHE
The Pion Decay Constants and the Rho-Meson Mass at Finite Temperature in the Hidden Local Symmetry
We study the temperature dependence of the pion decay constant and rho-meson
mass in the hidden local symmetry model at one loop. Using the standard
imaginary time formalism, we include the thermal effect of rho meson as well as
that of pion. We show that the pion gives a dominant contribution to the pion
decay constant and rho-meson contribution slightly decreases the critical
temperature. The rho-meson pole mass increases as T^4/m_\rho^2 at low
temperature dominated by the pion-loop effect. At high temperature, although
the pion-loop effect decreases the rho-meson mass, the rho-loop contribution
overcomes the pion-loop contribution and rho-meson mass increases with
temperature. We also show that the conventional parameter a is stable as the
temperature increases.Comment: We added a comment on the correction to the rho-meson mass from the
omega-pi loop. This is the final version to be published in Phys. Rev. D. 19
pages (LaTeX-RevTeX), 7 PostScript figure
radiative decay of resonances dynamically generated from the vector meson-vector meson interaction
We evaluate the radiative decay into a vector a pseudoscalar and a photon of
several resonances dynamically generated from the vector vector interaction.
The process proceeds via the decay of one of the vector components into a
pseudoscalar and a photon, which have an invariant mass distribution very
different from phase space as a consequence of the two vector structure of the
resonances. Experimental work along these lines should provide useful
information on the nature of these resonances.Comment: 13 pages, 5 figure
Constituent quark model for baryons with strong quark-pair correlations and non-leptonic weak transitions of hyperon
We study the roles of quark-pair correlations for baryon properties, in
particular on non-leptonic weak decay of hyperons. We construct the quark wave
function of baryons by solving the three body problem explicitly with
confinement force and the short range attraction for a pair of quarks with
their total spin being 0. We show that the existence of the strong quark-quark
correlations enhances the non-leptonic transition amplitudes which is
consistent with the data, while the baryon masses and radii are kept to the
experiment.Comment: 4 pages, 2 figures, talk presented at KEK-Tanashi International
Symposium on Physics of Hadrons and Nuclei, Tokyo, Japan, 14-17 Dec. 199
Vector and pseudoscalar charm meson radiative decays
Combining heavy quark effective theory and the chiral Lagrangian approach we
investigate radiative decays of pseudoscalar mesons. We first reanalyse
decays within the effective Lagrangian approach
using heavy quark spin symmetry, chiral symmetry Lagrangian, but including also
the light vector mesons. We then investigate decays
and calculate the and partial widths and branching ratios.Comment: 21 pages Latex, no figures, IJS-TP-94/19, TUM-31-62/94, NUHEP-TH-94-
Gauge Symmetry Enhancement and Radiatively Induced Mass in the Large N Nonlinear Sigma Model
We consider a hybrid of nonlinear sigma models in which two complex
projective spaces are coupled with each other under a duality. We study the
large N effective action in 1+1 dimensions. We find that some of the
dynamically generated gauge bosons acquire radiatively induced masses which,
however, vanish along the self-dual points where the two couplings
characterizing each complex projective space coincide. These points correspond
to the target space of the Grassmann manifold along which the gauge symmetry is
enhanced, and the theory favors the non-Abelian ultraviolet fixed point.Comment: 11 pages, REVTEX, typos are corrected, version to appear in Phys.
Rev.
Berry's phase for compact Lie groups
The Lie group adiabatic evolution determined by a Lie algebra parameter
dependent Hamiltonian is considered. It is demonstrated that in the case when
the parameter space of the Hamiltonian is a homogeneous K\"ahler manifold its
fundamental K\"ahler potentials completely determine Berry geometrical phase
factor. Explicit expressions for Berry vector potentials (Berry connections)
and Berry curvatures are obtained using the complex parametrization of the
Hamiltonian parameter space. A general approach is exemplified by the Lie
algebra Hamiltonians corresponding to SU(2) and SU(3) evolution groups.Comment: 24 pages, no figure
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