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

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

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 $M^3\otimes S^1$ 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

Multi-phases in gauge theories of 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 M^3 ⊗ S^1 is studied, and it is shown to possess three phases: Hosotani, Higgs and coexisting phases. The critical radius and the order of the phase transitions are determined explicitly. 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 the dynamical problem of the stabilization of the radius of a compactified space in the vicinity of a critical radius

Extended supersymmetry and its reduction on a circle with point singularities

We investigate $N$-extended supersymmetry in one-dimensional quantum mechanics on a circle with point singularities. For any integer $n$, $N=2n+1$ supercharges are explicitly constructed in terms of discrete transformations, and a class of singularities compatible with supersymmetry is clarified. In our formulation, the supersymmetry can be reduced to $M$-extended supersymmetry for any integer $M<N$. The degeneracy of the spectrum and spontaneous supersymmetry breaking are also studied.Comment: 36 pages, 5 figures, 2 table

Fermion Scattering off CP-Violating Electroweak Bubble Wall

A general prescription to solve the Dirac equation in the presence of CP-violating electroweak bubble wall is presented. The profile of the bubble wall is not specified except that the wall height is $m_0$ and zero deep in the broken- and the symmetric-phase regions, respectively, where $m_0$ is a fermion mass given by the Higgs-vacuum-expectation value and the Yukawa coupling. The CP-violating effects are evaluated by regarding CP-violating part of the bubble wall as a perturbation to CP-conserving solutions. The basic quantity, $R_{R\rightarrow L}-\bar R_{R\rightarrow L}$, which would contribute to the cosmological baryon asymmetry, is estimated for some typical profiles of the wall, where $R_{R\rightarrow L}$($\bar R_{R\rightarrow L}$) is the reflection coefficient of right-handed chiral fermion (anti-fermion).Comment: 30 pages, 2 figures ( uuencoded tar.Z file of PS files is appended ), plain TeX with phyzzx, tables and epsf,SAGA-HE-55--KYUSHU-HET-1