1,978 research outputs found

### A general formula of the effective potential in 5D SU(N) gauge theory on orbifold

We show a general formula of the one loop effective potential of the 5D SU(N)
gauge theory compactified on an orbifold, $S^1/Z_2$. The formula shows the case
when there are fundamental, (anti-)symmetric tensor and adjoint
representational bulk fields. Our calculation method is also applicable when
there are bulk fields belonging to higher dimensional representations. The
supersymmetric version of the effective potential with Scherk-Schwarz breaking
can be obtained straightforwardly. We also show some examples of effective
potentials in SU(3), SU(5) and SU(6) models with various boundary conditions,
which are reproduced by our general formula.Comment: 22 pages;minor corrections;references added;typos correcte

### Correct Effective Potential of Supersymmetric Yang-Mills Theory on M^4\times S^1

We study an ${\cal N}=1$ supersymmetric Yang-Mills theory defined on
$M^4\times S^1$. The vacuum expectation values for adjoint scalar field in
vector multiplet, though important, has been overlooked in evaluating one-loop
effective potential of the theory. We correctly take the vacuum expectation
values into account in addition to the Wilson line phases to give an expression
for the effective potential, and gauge symmetry breaking is discussed. In
evaluating the potential, we employ the Scherk-Schwarz mechanism and introduce
bare mass for gaugino in order to break supersymmetry. We also obtain masses
for the scalars, the adjoint scalar, and the component gauge field for the
$S^1$ direction in case of the SU(2) gauge group. We observe that large
supersymmetry breaking gives larger mass for the scalar. This analysis is
easily applied to the $M^4\times S^1/Z_2$ case.Comment: 12 pages, 1 figur

### Dynamical symmetry breaking in Gauge-Higgs unification of 5D ${\mathcal N}=1$ SUSY theory

We study the dynamical symmetry breaking in the gauge-Higgs unification of
the 5D ${\mathcal N}=1$ SUSY theory, compactified on an orbifold, $S^1/Z_2$.
This theory identifies Wilson line degrees of freedoms as ``Higgs doublets''.
We consider $SU(3)_c \times SU(3)_W$ and SU(6) models, in which the gauge
symmetries are reduced to $SU(3)_c \times SU(2)_L \times U(1)_Y$ and $SU(3)_c
\times SU(2)_L \times U(1)_Y \times U(1)$, respectively, through the
orbifolding boundary conditions. Quarks and leptons are bulk fields, so that
Yukawa interactions can be derived from the 5D gauge interactions. We estimate
the one loop effective potential of ``Higgs doublets'', and analyze the vacuum
structures in these two models. We find that the effects of bulk quarks and
leptons destabilize the suitable electro-weak vacuum. We show that the
introduction of suitable numbers of extra bulk fields possessing the suitable
representations can realize the appropriate electro-weak symmetry breaking.Comment: 15 pages, 4 figures;disscutions on Higgs quartic couplings adde

### Baryogenesis from Dark Sector

We propose a novel mechanism to generate a suitable baryon asymmetry from
dark (hidden) sector. This is a Baryogenesis through a reverse pathway of the
"asymmetric dark matter" scenario. In the mechanism, the asymmetry of dark
matter is generated at first, and it is partially transferred into a baryon
asymmetry in the standard model sector. This mechanism enables us not only to
realize the generation of the baryon asymmetry but also to account for the
correct amount of dark matter density in the present universe within a simple
framework.Comment: 7 page

### Analytic Solutions to the RG Equations of the Neutrino Physical Parameters

In the case of two generation neutrinos, the energy-scale dependence of the
lepton-flavor mixing matrix with Majorana phase can be governed by only one
parameter r, which is the ratio between the diagonal elements of neutrino mass
matrix. By using this parameter r, we derive the analytic solutions to the
renormalization group equations of the physical parameters, which are the
mixing angle, Majorana phase, and the ratio of the mass-squared difference to
the mass squared of the heaviest neutrino. The energy-scale dependence of the
Majorana phase is clarified by using these analytic solutions. The instability
of the Majorana phase causes in the same parameter region in which the mixing
angle is unstable against quantum corrections.Comment: LaTeX2e, 9 pages, 6 figure

### The effects of Majorana phases in three-generation neutrinos

Neutrino-oscillation solutions for the atmospheric neutrino anomaly and the
solar neutrino deficit can determine the texture of the neutrino mass matrix
according to three types of neutrino mass hierarchies as Type A: $m_1^{} \ll
m_2^{} \ll m_3^{}$,
Type B: $m_1^{} \sim m_2^{} \gg m_3^{}$, and Type C: $m_1^{} \sim m_2^{} \sim
m_3^{}$, where $m_i$ is the $i$-th generation neutrino absolute mass. The
relative sign assignments of neutrino masses in each type of mass hierarchies
play the crucial roles for the stability against quantum corrections. Actually,
two physical Majorana phases in the lepton flavor mixing matrix connect among
the relative sign assignments of neutrino masses. Therefore, in this paper we
analyze the stability of mixing angles against quantum corrections according to
three types of neutrino mass hierarchies (Type A, B, C) and two Majorana
phases. Two phases play the crucial roles for the stability of the mixing
angles against the quantum corrections.Comment: LaTeX2e, 15 pages, 8 figure

### Multi-Higgs Mass Spectrum in Gauge-Higgs Unification

We study an SU(2) supersymmetric gauge model in a framework of gauge-Higgs
unification. Multi-Higgs spectrum appears in the model at low energy. We
develop a useful perturbative approximation scheme for evaluating effective
potential to study the multi-Higgs mass spectrum. We find that both
tree-massless and massive Higgs scalars obtain mass corrections of similar size
from finite parts of the loop effects. The corrections modify multi-Higgs mass
spectrum, and hence, the loop effects are significant in view of future
verifications of the gauge-Higgs unification scenario in high-energy
experiments.Comment: 32 pages; typos corrected and a few comments added, published versio

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