The Standard Model Gauge Symmetry from Higher-Rank Unified Groups in Grand Gauge-Higgs Unification Models

We study grand unified models in the five-dimensional space-time where the extra dimension is compactified on $S^1/Z_2$. The spontaneous breaking of unified gauge symmetries is achieved via vacuum expectation values of the extra-dimensional components of gauge fields. We derive one-loop effective potentials for the zero modes of the gauge fields in SU(7), SU(8), SO(10), and $E_6$ models. In each model, the rank of the residual gauge symmetry that respects the boundary condition imposed at the orbifold fixed points is higher than that of the standard model. We verify that the residual symmetry is broken to the standard model gauge symmetry at the global minima of the effective potential for certain sets of bulk fermion fields in each model.Comment: 34 pages, 1 figure, clarifications added in Sec. 6, published versio

Superconducting nanowire single-photon detectors with non-periodic dielectric multilayers

We present superconducting nanowire single-photon detectors (SSPDs) on non-periodic dielectric multilayers, which enable us to design a variety of wavelength dependences of optical absorptance by optimizing the dielectric multilayer. By adopting a robust simulation to optimize the dielectric multilayer, we designed three types of SSPDs with target wavelengths of 500 nm, 800 nm, and telecom range respectively. We fabricated SSPDs based on the optimized designs for 500 and 800 nm, and evaluated the system detection efficiency at various wavelengths. The results obtained confirm that the designed SSPDs with non-periodic dielectric multilayers worked well. This versatile device structure can be effective for multidisciplinary applications in fields such as the life sciences and remote sensing that require high efficiency over a precise spectral range and strong signal rejection at other wavelengths

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

COMPARISON OF SUCCESS AND FAILURE TRIALS BY FEMALE DISCUS THROWERS

The purpose of this study was to investigate the factors that caused poor records of female discus throwers by comparing their success and failure trials in the same competition. Seven female discus throwers were recorded with two video cameras in competition and their trials were analysed by a three-dimensional DLT method. The increase in discus speed from L-ON (the left foot grounded) to REL (discus was released) was smaller in failure trials than in success trials. The horizontal rotation of shoulders and hips from L-ON to REL was smaller in failure trials than in success trials. The upper limb moved towards throwing direction earlier in failure trials than in success trials. The decrease in twist angle of trunk at L-ON is considered to relate poor records in female discus throwers

On representation matrices of boundary conditions in SU(n)SU(n) gauge theories compactified on two-dimensional orbifolds

We study the existence of diagonal representatives in each equivalence class of representation matrices of boundary conditions in $SU(n)$ gauge theories compactified on the orbifolds $T^2/{\mathbb Z}_N$ ($N = 2, 3, 4, 6$). Using constraints, unitary transformations and gauge transformations, we examine whether the representation matrices can simultaneously become diagonal or not. We show that at least one diagonal representative necessarily exists in each equivalence class on $T^2/{\mathbb Z}_2$ and $T^2/{\mathbb Z}_3$, but the representation matrices on $T^2/{\mathbb Z}_4$ and $T^2/{\mathbb Z}_6$ can contain not only diagonal matrices but also non-diagonal $2 \times 2$ ones and non-diagonal $3 \times 3$ and $2 \times 2$ ones, respectively, as a member of block-diagonal submatrices. These non-diagonal matrices have discrete parameters, which means that the rank-reducing symmetry breaking can be caused by the discrete Wilson line phases.Comment: 44 page

New insights into electron transport due to azimuthal drift in a Hall effect thruster

International audiencePartially magnetized plasmas in the Hall effect thrusters remain poorly understood primarily due to the electron transport in the cross-field direction. It is recently discussed that the drift-diffusion approximation is invalid for the electron dynamics in the presence of a large drift velocity. It is therefore possible that the anomalous electron transport is strongly related with the presence of an azimuthal drift. In this paper, we discuss the importance of the azimuthal drift on cross-field electron transport based on some recent results from a one-dimensional particle-in-cell simulation, two-dimensional particle-in-cell simulation, and laser Thomson scattering measurements