Inclusive Higgs boson pair production through the mechanism of gauge bo-ew ) in the linear colliders ILC and CLIC. This kind of processes is highly sensitive to the trilinear (3H) Higgs boson self-interactions and hence can be a true keystone in the reconstruction of the Higgs potential. For example, in the ILC at 1 TeV, the most favorable scenarios yield cross-sections up to roughly 1 pb, thus entailing 10 5 events per 100 fb -1 of integrated luminosity, whilst remaining fully consistent with the perturbativity and unitarity bounds on the 3H couplings, the electroweak precision data and the constraints from B(b → sγ). Comparing with other competing mechanisms, we conclude that the Higgs boson-pair events could be the dominant signature for Higgs-boson production in the TeV-class linear colliders for a wide region of the 2HDM parameter space, with no counterpart in the Minimal Supersymmetric Standard Model (MSSM). Owing to the extremely clean environment of these colliders, inclusive 2H events should allow a comfortable tagging and might therefore open privileged new vistas into the structure of the Higgs potential.

Singlet Higgs bosons present in extensions of the MSSM can have sizable Yukawa couplings to the b quark and the τ lepton for large values of tan β at the 1-loop level. We present an effective Lagrangian which incorporates these tan β-enhanced Yukawa couplings and which enables us to study their effect on singlet Higgs-boson phenomenology within the context of both the mnSSM and the NMSSM. In particular, we find that the loop-induced coupling can be a significant effect for the singlet pseudoscalar, and may dominate its decay modes. Further implications of the tan β-enhanced Yukawa couplings for the phenomenology of the singlet Higgs bosons are briefly discussed.

The current 7 TeV run of the LHC experiment shall be able to probe gluino and squark masses up to values larger than 1 TeV. Assuming that hints for SUSY are found in the jets plus missing energy channel by the end of a 5 fb −1 run, we explore the flavour constraints on three models with a CMSSM-like spectrum: the CMSSM itself, a Seesaw extension of the CMSSM, and Flavoured CMSSM. In particular, we focus on decays that might have been measured by the time the run is concluded, such as B s → µµ and µ → eγ. We also analyse constraints imposed by neutral meson bounds and electric dipole moments. The interplay between collider and flavour experiments is explored through the use of three benchmark scenarios, finding the flavour feedback useful in order to determine the model parameters and to test the consistency of the different models.

Higgs singlet superfields are usually present in most extensions of the minimal supersymmetric standard model that address the -problem, such as the next-to-minimal supersymmetric standard model and the minimal nonminimal supersymmetric standard model. Employing a gauge-and flavor-covariant effective Lagrangian formalism, we show how the singlet-Higgs bosons of such theories can have significant contributions to B-meson flavor-changing neutral current observables for large values of tan * 50 at the 1-loop level. Illustrative results are presented including effects on the B s and B d mass differences and on the rare decay B s ! þ À . In particular, we find that depending on the actual value of the lightest singlet pseudoscalar mass in the next-to-minimal supersymmetric standard model, the branching ratio for B s ! þ À can be enhanced or even suppressed with respect to the standard model prediction by more than 1 order of magnitude.