119423425
Large tan beta SUSY QCD corrections to B -> X_s gamma
The charged-Higgs boson contributions to the Wilson coefficients C_7 and C_8, relevant for the decay B -> X_s gamma, are discussed in supersymmetric models at large tan beta. These contributions receive two-loop O(alpha_s tan beta) corrections by squark-gluino subloops, which are possibly large and nondecoupling in the limit of heavy superpartners. In previous studies, the relevant two-loop Feynman integrals were approximated by using an effective two-Higgs-doublet lagrangian. However, this approximation is theoretically justified only when the typical supersymmetric scale M_SUSY is sufficiently larger than the electroweak scale m_weak \sim (m_W,m_t) and the mass of the charged-Higgs boson m_{H^\pm}. Here we evaluate these two-loop integrals exactly and compare the results with the existing, approximated ones. We then examine the validity of this approximation beyond the region where it has been derived, i.e. for m_H \gtap M_SUSY and/or M_SUSY \sim m_weak.
2853034
Two-loop renormalization of tan beta and its gauge dependence
Renormalization of two-loop divergent corrections to the vacuum expectation values (v_1, v_2) of the two Higgs doublets in the minimal supersymmetric standard model, and their ratio $\tan\beta=v_2/v_1$, is discussed for general R_{\xi} gauge fixings. When the renormalized (v_1, v_2) are defined to give the minimum of the loop-corrected effective potential, it is shown that, beyond the one-loop level, the dimensionful parameters in the R_{\xi} gauge fixing term generate gauge dependence of the renormalized $\tan\beta$. Additional shifts of the Higgs fields are necessary to realize the gauge-independent renormalization of $\tan\beta$.
11356307
Two-loop renormalization of gaugino masses in general supersymmetric gauge models.
We calculate the two-loop renormalization group equations for the running gaugino masses in general supersymmetry (SUSY) gauge models, improving our previous result. We also study its consequences on the unification of the gaugino masses in the SUSY SU(5) model. The two-loop correction to the one-loop relation [ital m][sub [ital i]]([mu])[proportional to][alpha][sub [ital i]]([mu]) is found to be of the order of a few percent.
17333378
SUSY - QCD corrections to top and bottom squark decays into Higgs bosons
We calculate the $\mathcal{O}({\ensuremath{\alpha}}_{s})$ SUSY-QCD corrections to the widths of top and bottom squark decays into Higgs bosons within the minimal supersymmetric standard model. We give the complete analytical formulas, paying particular attention to the on-shell renormalization of the soft SUSY-breaking parameters. We also perform a detailed numerical analysis of both top and bottom squark decays into all Higgs bosons ${h}^{0},$ ${H}^{0},$ ${A}^{0},$ and ${H}^{\ifmmode\pm\else\textpm\fi{}}.$ We find that the SUSY-QCD corrections are significant, mostly negative, and of the order of a few ten percent.
16486262
SUSY--QCD Corrections to Higgs Particle Decays into Quarks and Squarks
We study the decays of the Higgs bosons $H^{\pm}$, $H^0$, and $A^0$ within the Minimal Supersymmetric Standard Model. For decays into quarks and squarks we include the supersymmetric QCD radiative corrections. We find that the corrections are significant and can go up to 50%. The supersymmetric decay modes $H^+ \to \tilde t \bar{\tilde b}$ and $H^0 (A^0) \to \tilde t \bar{\tilde t}$ can be dominant in a wide range of the model parameters due to the large Yukawa couplings and mixings of $\tilde t$ and $\tilde b$.
16212962
Motivations for and implications of nonuniversal GUT scale boundary conditions for soft SUSY breaking parameters
We outline several well-motivated models in which GUT boundary conditions for SUSY breaking are non-universal. The diverse phenomenological implications of the non-universality for SUSY discovery at LEP2, the Tevatron, the LHC and the NLC are sketched.
119118937
Impacts of non-geometric moduli on effective theory of 5D supergravity
A bstract5D supergravity generically has moduli other than the radion that belong to 5D vector multiplets. We summarize the impacts of such non-geometric moduli on 4D effective theory of 5D supergravity on S1/Z2. We mainly discuss the structure of the effective Kähler potential including the one-loop quantum corrections. As an illustrative example, we construct a model in which the size of the extra dimension is stabilized at an exponentially large value compared to the Planck length, which is similar to the LARGE volume scenario in string theory.