Durmus A. Demir

Effects of the supersymmetric phases on the neutral Higgs sector

By using the effective potential approximation and taking into account the dominant top quark and scalar top quark loops, radiative corrections to the MSSM Higgs potential are computed in the presence of the supersymmetric CP-violating phases. It is found that the lightest Higgs scalar remains essentially CP even as in the CP-invariant theory whereas the other two scalars are heavy and do not have definite CP properties. The supersymmetric CP-violating phases are shown to modify significantly the decay rates of the scalar to fermion pairs.

B ---> X(s) gamma in supersymmetry with explicit CP violation

We discuss B ! Xs decay in both constrained and unconstrained supersymmetric models with explicit CP violation within the minimal flavor violation scheme by including tan {enhanced large contributions beyond the leading order. In this analysis, we take into account the relevant cosmological and collider bounds, as well as electric dipole moment constraints. In the unconstrained model, there are portions of the parameter space yielding a large CP asymmetry at leading order (LO). In these regions, we nd that the CP phases satisfy certain sum rules, e.g., the sum of the phases of the parameter and the stop trilinear coupling centralize around with a width determined by the experimental bounds. In addition, at large values of tan , the sign of the CP asymmetry tracks the sign of the gluino mass, and the CP asymmetry is signicantly larger than the LO prediction. In the constrained minimal supersymmetric standard model based on minimal supergravity, we nd that the decay rate is sensitive to the phase of the universal trilinear coupling. This sensitivity decreases at large values of the universal gauino mass. We also show that for a given set of the mass parameters, there exists a threshold value of the phase of the universal trilinear coupling which grows with tan and beyond which the experimental bounds are satised. In both supersymmetric scenarios, the allowed ranges of the CP phases are wide enough to have phenomenological consequences.

Hadronic EDMs, the Weinberg Operator, and Light Gluinos

We reexamine questions concerning the contribution of the three-gluon Weinberg operator to the electric dipole moment of the neutron, and provide several QCD sum-rule-based arguments that the result is smaller than\char22{}but nevertheless consistent with\char22{}estimates which invoke naive dimensional analysis. We also point out a regime of the minimal supersymmetric standard model parameter space with light gluinos for which this operator provides the dominant contribution to the neutron electric dipole moment due to enhancement via the dimension five color electric dipole moment of the gluino.

Higgs boson couplings to quarks with supersymmetric CP and flavor violations

Abstract In minimal supersymmetric model (SUSY) with a light Higgs sector, explicit CP violation and most general flavor mixings in the sfermion sector, integration of the superpartners out of the spectrum induces potentially large contributions to the Yukawa couplings of light quarks via those of the heavier ones. These corrections can be sizeable even for moderate values of tanβ, and remain nonvanishing even if all superpartners decouple. When the SUSY breaking scale is close to the electroweak scale, the Higgs exchange effects can compete with the gauge boson and box diagram contributions to rare processes, and their partial cancellations can lead to relaxation of the existing bounds on flavor violation sources. In this case there exist sizeable enhancements in flavor-changing Higgs decays. When the superpartners completely decouple, however, the Higgs mediation becomes the dominant SUSY contribution to rare processes the saturation of which, without a strong suppression of the flavor mixings, prefers large tanβ and certain ranges for the CP-odd phases. The decay rate of the lightest Higgs into light down quarks becomes comparable with that into the bottom quark. Moreover, the Higgs decay into the up quark is significantly enhanced. There are observable implications for rare processes, atomic electric dipole moments, and collider searches for Higgs bosons.

Inflation with non-minimal coupling: Metric vs. Palatini formulations

We analyze non-minimally coupled scalar field theories in metric (second-order) and Palatini (first-order) formalisms in a comparative fashion. After contrasting them in a general setup, we specialize to inflation and find that the two formalisms differ in their predictions for various cosmological parameters. The main reason is that dependencies on the non-minimal coupling parameter are different in the two formalisms. For successful inflation, the Palatini approach prefers a much larger value for the non-minimal coupling parameter than the Metric approach. Unlike the Metric formalism, in Palatini, the inflaton stays well below the Planck scale whereby providing a natural inflationary epoch.

Nonlinearly realized local scale invariance: Gravity and matter

\stackrel{\ensuremath{\rightarrow}}{B}{K}^{*}{l}^{\ensuremath{-}}{l}^{+}(l=\ensuremath{\mu},\ensuremath{\tau})

Vacuum Energy as the Origin of the Gravitational Constant

is analyzed in a minimally extended standard model in which the Wilson coefficients have new CP-odd phases. The sensitivity of the CP asymmetry and lepton polarization asymmetries to the new phases is discussed. It is found that the CP asymmetry is sensitive to the new phase in the Wilson coefficient

Forward-backward asymmetry of B → (π,K)ℓ +ℓ -: Supersymmetry at work

{C}_{7}

CP Violation in Supersymmetric U(1) ' Models

whereas the normal lepton polarization asymmetry is sensitive to the phase in the Wilson coefficient