Higgs and SUSY Higgs bosons at future linear collider

Theoretical overview on phenomenology of Higgs boson and SUSY Higgs boson at a future linear collider experiment is given as a Higgs and SUSY Higgs working group summary report for LCWS 2000.Comment: 14 page, 4 figures, Talk given at Linear Collider Workshop 2000, October 24 -28, 2000, Fermila

Manifestaion of SUSY in B decays

SUSY effects on various flavor changing neutral current processes are discussed in the minimal supergravity model and the SU(5) grand unified theory with right-handed neutrino supermultiplets. In particular, in the latter case the neutrino Yukawa coupling constants can be a source of the flavor mixing in the right-handed-down-type-squark sector. It is shown that due to this mixing the time-dependent CP asymmetry of radiative B decay can be as large as 30% and the ratio of $B_s$-$\bar{B}_s$ mixing and $B_d$-$\bar{B}_d$ mixing deviates from the prediction in the standard model and the minimal supergravity model without the neutrino interaction.Comment: 7 pages, 2 figures, talk given at the Third International Conference on B Physics and CP Violation, December 3 -7, 1999, Taipe

Cancellation Mechanism of FCNCs in S_4 x Z_2 Flavor Symmetric Extra U(1) Model

We propose a E_6 inspired supersymmetric model with a non-Abelian discrete flavor symmetry; SU(3)_c x SU(2)_W x U(1)_Y x U(1)_X x S_4 x Z_2. In our scenario, the additional abelian gauge symmetry; U(1)_X, not only solves the mu-problem in the minimal Supersymmetric Standard Model(MSSM), but also requires new exotic fields which play an important role in solving flavor puzzles. If our exotic quarks can be embedded into a S_4 triplet, which corresponds to the number of the generation, one finds that dangerous proton decay can be well-suppressed. Hence, it might be expected that the generation structure for lepton and quark in the SM(Standard Model) can be understood as a new system in order to stabilize the proton in a supersymemtric standard model (SUSY). Moreover, due to the nature of the discrete non-Abelian symmetry itself, Yukawa coupling constants of our model are drastically reduced. In our previous work, we actually have found much success. However, we also have to solve Higgs mediated FCNC at tree level, as is often the case with such extended Higgs models. In this paper, we propose a promising mechanism which could make cancellation between Higgs and SUSY contributions.Comment: 19 pages, 2 tables, no figures. Title is slightly changed and minor parts are modifie

Extracting SUSY Parameters from the Higgs Boson Properties

We calculate the ratio of the two branching ratios, Br(h -> bb-bar) and Br(h -> cc-bar) + Br(h -> gg), in the minimal supersymmetric standard model taking into account the SUSY-loop corrections to the Higgs sector and the hbb-bar vertex. We show that the heavy Higgs mass can be extracted from the ratio, almost independently of other SUSY parameters, in the region of tan(beta) ~< 10.Comment: Talk given by S.Kiyoura at the Linear Collider Workshop 2000, October 24-28, 2000, Fermila