Radion and Higgs masses in gauge-Higgs unification

We evaluate the radion and Higgs masses in the gauge-Higgs unification models on the warped geometry, in which the modulus is stabilized by the Casimir energy. We analyze the one-loop effective potential and clarify the dependences of those masses on the Wilson line phase $\theta_H$. The radion mass varies 1-30GeV for $0.06\leq\sin\theta_H\leq 0.3$, while the Higgs mass is 150-200 GeV and depends on $\theta_H$ only logarithmically. The radion couplings to the standard model particles are sensitive to the warp factor, and are too small to detect at colliders in the region where the five-dimensional description is valid.Comment: 20 pages, 3 figures; text modified, references adde

Geometry mediated supersymmetry breaking

We investigate SUSY breaking mediated through the deformation of the spacetime geometry due to the backreaction of a nontrivial configuration of a bulk scalar field. To illustrate its features, we work with a toy model in which the bulk is four dimensions. Using the superconformal formulation of SUGRA, we provide a systematic method of deriving the 3D effective action expressed by the superfields.Comment: 4 pages, contribution to the Proceedings of the 12th International Conference on Supersymmetry and Unification of the Fundamental Interactions, June 17-23, 2004, Tsukuba, Japa

6D gauge-Higgs unification on T^2/Z_N with custodial symmetry

We investigate the gauge-Higgs unification models compactified on T^2/Z_N that have the custodial symmetry. We select possible gauge groups, orbifolds and representations of the matter fermions that are consistent with the custodial symmetry, by means of the group theoretical analysis. The best candidate we found is 6D SU(3)_C x U(4) gauge theory on T^2/Z_3 and the third generation quarks are embedded into bulk fermions that are the symmetric traceless rank-2 tensor of SO(6).Comment: 38 pages, 1 table, a reference adde

Full diffeomorphism and Lorentz invariance in 4D N=1{\cal N}=1 superfield description of 6D SUGRA

We complete the four-dimensional ${\cal N}=1$ superfield description of six-dimensional supergravity. The missing ingredients in the previous works are the superfields that contain the sechsbein $e_4^{\;\;\underline{\nu}}$, $e_5^{\;\;\underline{\nu}}$, $e_\mu^{\;\;\underline{4}}$, $e_\mu^{\;\;\underline{5}}$ and the second gravitino. They are necessary to make the action invariant under the diffeomorphisms and the Lorentz transformations involving the extra dimensions. We find the corresponding superfield transformation laws, and show the invariance of the action under them. We also check that the resultant action reproduces the known superfield description of five-dimensional supergravity through the dimensional reduction.Comment: 45 pages, some comments adde