Solving the little hierarchy problem with a singlet and explicit μ terms.

We present a generalization of the next-to-minimal supersymmetric standard model, with an explicit μ term and a supersymmetric mass for the singlet superfield, as a route to alleviating the little hierarchy problem of the minimal supersymmetric standard model (MSSM). Though this model does not address the μ problem of the MSSM, we are able to generate masses for the lightest neutral Higgs boson up to 140 GeV with top squarks below the TeV scale, all couplings perturbative to the gauge unification scale, and with no need to fine-tune parameters in the scalar potential. This model more closely resembles the MSSM phenomenologically than the canonical next-to-minimal supersymmetric standard model.

Bd-->phi KS CP asymmetries as an important probe of supersymmetry.

The decay B(d)-->phi K(S) is a special probe of physics beyond the standard model (SM), since it has no SM tree level contribution. Motivated by recent data suggesting a deviation from the SM for its time-dependent CP asymmetry, we examine supersymmetric explanations. Chirality preserving contributions are generically small, unless gluino is relatively light.

Higgs-mediated tau-->3micro in the supersymmetric seesaw model.

Recent observations of neutrino oscillations imply nonzero neutrino masses and lepton flavor violation (LFV), most economically explained by the seesaw mechanism. Within the context of supersymmetry, LFV among the neutrinos can be communicated to the sleptons and from there to the charged leptons. We show that LFV can appear in the couplings of the neutral Higgs bosons, an effect that is strongly enhanced at large tan(beta.

New perspective on cosmic coincidence problems.

Cosmological data suggest that we live in an interesting period in the history of the universe when rho(Lambda) approximately rho(M) approximately rho(R). The occurrence of any epoch with such a "triple coincidence" is puzzling, while the question of why we happen to live during this special epoch is the "Why now?" problem. We introduce a framework which makes the triple coincidence inevitable; furthermore, the "Why now?" problem is transformed and greatly ameliorated.

Higgs-mediated B0 --> &mgr;(+)&mgr;(-) in minimal supersymmetry.

We demonstrate a new source for flavor-changing neutral currents within the minimal supersymmetric standard model. At moderate to large tanbeta, it is no longer possible to diagonalize the masses of the quarks in the same basis as their Yukawa couplings. This generates flavor-violating couplings of the form &bmacr;(R)d(L)straight phi and &bmacr;(R)s(L)straight phi where straight phi is any of the three neutral, physical Higgs bosons.