We study new physics effects on B decay processes including a final τ particle, namely B → Dτ ν and B → τ ν. An important feature of these processes is that a charged Higgs boson can contribute to the decay amplitude at the tree level in models such as Two Higgs Doublet Model and the Minimal Supersymmetric Standard Model (MSSM). We derive a resummed effective Lagrangian for charged-Higgs mediated interactions in the MSSM with the Minimal Flavor Violation. Including supersymmetric (SUSY) loop corrections for downtype-quark and charged-lepton Yukawa couplings, we calculate the branching ratios of the B → Dτ ν and B → τ ν processes. We find that SUSY correction due to gluino-sbottom diagrams can change the Higgs exchange contribution by ±50%, whereas stau-neutralino diagrams can make corrections up to 20%. We also discuss relationship between SUSY corrections in the tauonic decays and flavor changing neutral current processes such as B s → µ + µ − and b → sγ. §1. IntroductionRecent success of B factory experiments at KEK and SLAC has proved that B physics provide a very promising way to explore physics in and beyond the Standard Model (SM). The Kobayashi-Maskawa mechanism 1) of the CP violation in the quark sector has been established from the precise determination of the CP asymmetry in B → J/ψK S and related modes. 2), 3) B factory experiments have made many new observations such as the branching ratio of the b → sll 4) and CP violation in the B → φK S mode, 5), 6) which are known to be sensitive to new physics effects.In future, more information on B decays will be obtained at current B factories as well as hadron B experiments at Tevatron and LHC. Furthermore, the future upgrade of the e + e − asymmetric B factory, Super B Factory, is discussed, where the goal of the luminosity is 50-100 times more than the current achieved luminosity. 7)We study here new physics effects on B decay processes including a final τ particle, namely B → Dτ ν and B → τ ν. An important feature of these processes is that a charged Higgs boson can contribute to the decay amplitude at the tree level in models such as Two Higgs Doublet Model (2HDM) and the Minimal Supersymmetric Standard Model (MSSM). From the experimental side, since at least two neutrinos are present in the final state in the signal side, full-reconstruction is required for the B decay in the opposite side. For the B → Dτ ν process, the branching ratio is not at

We study the effect of the Higgs-exchange diagram for the lepton flavor violating muon-electron conversion process in nuclei in the supersymmetric seesaw model. The contribution is significant for a large value of tan β and a small value of a neutral heavy Higgs boson mass, in which case the ratio of the branching ratios of B(µN → eN)/B(µ → eγ) is enhanced. We also show that the target atom dependence of the conversion branching ratio provides information on the size of the Higgs exchange diagram. *

Phenomenological issues of no-scale structure of Kähler potential are reexamined, which arises in various approaches to supersymmetry breaking.When no-scale boundary conditions are given at the Grand Unified scale and universal gaugino masses are postulated, a bino mass is quite degenerate with right-handed slepton masses and the requirement that the lightest superparticle (LSP) be neutral supplemented with slepton searches at LEP200 severely constrains allowed mass regions of superparticles. The situation drastically changes if one moderately relaxes the assumption of the universal gaugino masses. After reviewing some interesting scenarios where non-universal gaugino masses arise, we show that the non-universality diminishes the otherwise severe constraint on the superparticle masses, and leads a variety of superparticle mass spectra: in particular the LSP can be a wino-like neutralino, a higgsino-like neutralino, or even a sneutrino, and also left-handed sleptons can be lighter than right-handed ones.

Recently, the E821 experiment at the Brookhaven National Laboratory announced their latest result of their muon g − 2 measurement which is about 2.6-σ away from the standard model prediction. Taking this result seriously, we examine the possibility to explain this discrepancy by the supersymmetric contribution. Our analysis is performed in the framework of the unconstrained supersymmetric standard model which has free seven parameters relevant to muon g − 2. We found that, in the case of large tan β, sparticle masses are allowed to be large in the region where the SUSY contribution to the muon g − 2 is large enough, and hence the conventional SUSY search may fail even at the LHC. On the contrary, to explain the discrepancy in the case of small tan β, we found that (i) sleptons and SU (2) L gauginos should be light, and (ii) negative search for the Higgs boson severely constrains the model in the framework of the mSUGRA and gauge-mediated model. *

An analysis is made on bottom-tau Yukawa unification in supersymmetric (SUSY) SU(5) grand unified theory (GUT) in the framework of minimal supergravity, in which the parameter space is restricted by some experimental constraints including Br(b → sγ) and muon g − 2. The bottom-tau unification can be accommodated to the measured branching ratio Br(b → sγ) if superparticle masses are relatively heavy and higgsino mass parameter µ is negative. On the other hand, if we take the latest muon g − 2 data to require positive SUSY contributions, then wrong-sign threshold corrections at SUSY scale upset the Yukawa unification with more than 20 percent discrepancy. It has to be compensated by superheavy threshold corrections around the GUT scale, which constrains models of flavor in SUSY GUT. A pattern of the superparticle masses preferred by the three requirements is also commented. *