647 research outputs found
Quantization Ambiguity and Supersymmetric Ground State Wave Functions
Supersymmetric ground state wave functions of a model of supersymmetric
quantum mechanics on (supersymmetric simple pendulum) are studied.
Supersymmetry can be broken due to the existence of an undetermined parameter,
which is interpreted as a gauge field and appears as a firm consequence of
quantization on a space with a nontrivial topology such as . The breaking
does not depend on the leading term of the superpotential, contrary to the
usual case. The mechanism of supersymmetry breaking is similar to that through
boundary conditions of fields in supersymmetric quantum field theory on
compactified space. The supersymmetric harmonic oscillator is realized in the
limit of the infinite radius of with the strength of the oscillator being
constant.Comment: 17 pages, final version to appear in Phys. Rev.
Symmetry and Z_2-Orbifolding Approach in Five-dimensional Lattice Gauge Theory
In a lattice gauge-Higgs unification scenario using a Z_2-orbifolded
extra-dimension, we find a new global symmetry in a case of SU(2) bulk gauge
symmetry. It is a global symmetry on sites in a fixed point with respect to
Z_2-orbifolding, independent of the bulk gauge symmetry. It is shown that the
vacuum expectation value of a Z_2-projected Polyakov loop is a good order
parameter of the new symmetry. The effective theory on lattice is also
discussed.Comment: 13 pages, 3 figures; refined the explanation
Scattering with Baryon Number Violation -- The Case of Higgs Particle Production --
\noindent A formalism based on path-integral expression of time-evolution
operator during tunneling at a finite energy proposed by the authors is applied
to gauge-Higgs system to produce Higgs particles with .
Instead of starting from instanton tunneling at the zero energy, a classical
bounce solution giving sphaleron (instanton) action at high (low) energies is
used as the tunneling configuration. Fourier transform of the bounce
configuration in coherent state expression at the entrance and exit of the
tunneling plays an important role. Numerical results at various energies for
are given. Though the cross section with
results from a severe cancellation of several large quantities in the leading
order as occured in the instanton calculus, it seems unlikely that the cross
section grows as largely as to reach unitarity bound at energies . It is pointed out that the actual value of the
gauge coupling constant may be too large to take the weak coupling limit.}Comment: modified PHYZZX(included), 4 Figures (not included), SAGA-HE-46 :
KYUSHU-HET-
A Cutoff Constrained by the Oblique Parameters in Electroweak Theory with Two Massless Higgs Doublets
Electroweak theory with two massless Higgs doublets is studied by solving
renormalization group equations for coupling constants in one-loop
approximation. A cutoff~, at which one of quartic couplings in the
Higgs potential blows up, is obtained by imposing constraints from the oblique
parameter on the quartic couplings at low energy. We find ~TeV at the Higgs mass GeV. The cutoff is at
most about TeV even if we take into account the LEP lower bound of
GeV. It cannot reach the Planck or GUT scale due to severe
experimental constraints. It is impossible in the model to realize a large
gauge hierarchy as suggested many years ago by S. Weinberg.Comment: 20 pages, Latex, 3 figures are available upon reques
A New Mechanism of Spontaneous SUSY Breaking
We propose a new mechanism of spontaneous supersymmetry breaking. The
existence of extra dimensions with nontrivial topology plays an important role.
We investigate new features resulted from the mechanism in two simple
supersymmetric Z_2 and U(1) models. One of remarkable features is that there
exists a phase in which the translational invariance for the compactified
directions is broken spontaneously, accompanying the breakdown of the
supersymmetry. The mass spectrum of the models appeared in reduced dimensions
is a full of variety, reflecting the highly nontrivial vacuum structure of the
models. The Nambu-Goldstone bosons (fermions) associated with breakdown of
symmetries are found in the mass spectrum. Our mechanism also yields quite
different vacuum structures if models have different global symmetries.Comment: 43 pages, 3 figure
Multi-phases in gauge theories on non-simply connected spaces
It is pointed out that phase structures of gauge theories compactified on
non-simply connected spaces are not trivial. As a demonstration, an SU(2) gauge
model on is studied and is shown to possess three phases:
Hosotani, Higgs and coexisting phases. The critical radius and the order of the
phase transitions are explicitly determined. A general discussion about phase
structures for small and large scales of compactified spaces is given. The
appearance of phase transitions suggests a GUT scenario in which the gauge
hierarchy problem is replaced by a dynamical problem of how to stabilize a
radius of a compactified space in close vicinity to a critical radius.Comment: 12 pages, 1 figur
Chiral Charge Flux and Electroweak Baryogenesis
By treating CP-violating interaction of the electroweak bubble wall as a
perturbative term, chiral charge flux through the bubble wall is estimated. It
is found that the absolute value of the flux has a sharp peak at with . Here
is the fermion mass, is the wall thickness, is the temperature
at which the bubbles are growing, is the wall velocity, is the
chiral charge of the relevant left(right)-handed fermion and is
the measure of CP violation.Comment: 10 pages, 4 figures ( not included, hard copies are available upon
request ), plain TeX with phyzzx
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