Flavor Mixing in the Gauge-Higgs Unification

Gauge-Higgs unification is the fascinating scenario solving the hierarchy problem without supersymmetry. In this scenario, the Standard Model (SM) Higgs doublet is identified with extra component of the gauge field in higher dimensions and its mass becomes finite and stable under quantum corrections due to the higher dimensional gauge symmetry. On the other hand, Yukawa coupling is provided by the gauge coupling, which seems to mean that the flavor mixing and CP violation do not arise at it stands. In this talk, we discuss that the flavor mixing is originated from simultaneously non-diagonalizable bulk and brane mass matrices. Then, this mechanism is applied to various flavor changing neutral current (FCNC) processes via Kaluza-Klein (KK) gauge boson exchange at tree level and constraints for compactification scale are obtained.Comment: 5 pages, prepared for the proceedings of the International Workshop on Grand Unified Theories (GUT2012) held at Yukawa Institute for Theoretical Physics, March 15-17 2012, Kyoto, Japa

Magnetic Ground State of Pr0.89_{0.89}LaCe0.11_{0.11}CuO4+α−δ_{4+\alpha-\delta} with Varied Oxygen Depletion Probed by Muon Spin Relaxation

The magnetic ground state of an electron-doped cuprate superconductor Pr$_{1-x}$LaCe$_x$CuO$_{4+\alpha-\delta}$ ($x=0.11, \alpha\simeq0.04$) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, $0.03\le\delta\le0.12$. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of $\delta$-dependence for the random magnetism and the multiplet pattern of muon Knight shift at higher fields strongly suggest that the random moments are associated with excited Pr$^{3+}$ ions under crystal electric field.Comment: 6 pages, 4 figures, submitted to J. Phys. Soc. Jp

Theoretical study of transition radiation from hot electrons generated in the laser-solid interaction

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 10(7), 2994-3003, 2003 and may be found at http://dx.doi.org/10.1063/1.157638

Characterization of preplasma produced by an ultrahigh intensity laser system

Copyright 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 11(8), 3721-3725, 2004 and may be found at http://dx.doi.org/10.1063/1.176077

Absence of magnetic field effect on static magnetic order in electron-doped superconductor Nd_{1.86}Ce_{0.14}CuO_4

Neutron-scattering experiments were performed to study the magnetic field effect on the electron-doped cuprate superconductor Nd_{1.86}Ce_{0.14}CuO_4, which shows the coexistence of magnetic order and superconductivity. The (1/2 3/2 0) magnetic Bragg intensity, which mainly originates from the order of both the Cu and Nd moments at low temperatures, shows no magnetic field dependence when the field is applied perpendicular to the CuO_{2} plane up to 10 T above the upper critical field. This result is significantly different from that reported for the hole-doped cuprate superconductors, in which the quasi-static magnetic order is noticeably enhanced under a magnetic field.Comment: 4 pages, 3 figure