Radiative Higgs-Sector CP Violation in the MSSM

We briefly review the phenomenological implications of the minimal supersymmetric standard model (MSSM) with explicit radiative breaking of CP invariance in the Higgs sector for the LEP2 and Tevatron colliders.Comment: 6 pages, talk given at PASCOS '99, Lake Tahoe, California, December 10-16, 199

Symmetries for SM Alignment in multi-Higgs Doublet Models

We derive the complete set of continuous maximal symmetries for Standard Model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs Doublet Models, with $n > 2$ Higgs doublets. Our results generalize the symmetries of SM alignment, without decoupling of large mass scales or fine-tuning, previously obtained in the context of two-Higgs Doublet Models.Comment: 12 pages, no figures, expanded version with significant clarifications adde

CP Violation in the Higgs Sector of the MSSM

Recently, it has been found that the tree-level CP invariance of the Higgs potential in the MSSM can be sizeably broken by loop effects due to soft-CP-violating trilinear interactions involving third generation scalar quarks. These soft-CP-violating couplings may be constrained by considering new two-loop contributions to the electron and neutron EDMs. The phenomenological consequences of such a minimal supersymmetric scenario of explicit CP violation at present and future colliders are briefly discussed.Comment: 11 pages, comments on the renormalization-scheme dependence of the radiatively-induced CP-odd Higgs phase adde

Anomalous Fermion Mass Generation at Three Loops

We present a novel mechanism for generating gauge-invariant fermion masses through global anomalies at the three loop level. In a gauge theory, global anomalies are triggered by the possible existence of scalar or pseudoscalar states and heavy fermions, whose masses may not necessarily result from spontaneous symmetry breaking. The implications of this mass-generating mechanism for model building are discussed, including the possibility of creating low-scale fermion masses by quantum gravity effects.Comment: 12 pages, 2 axodraw figures, to appear in MPL

Phenomenology of neutrino physics in the Kaluza-Klein theories of low scale gravity

We discuss the phenomenological consequences of theories which describe sterile neutrinos in large extra dimensions. We show that the Kaluza-Klein tower of the singlet neutrinos, albeit tiny individual contribution in electroweak processes, act cumulatively, giving rise to non-universality of the weak interactions of the light neutrinos and to flavour-violating radiative processes. Owing to these non-decoupling effects of th Kaluza--Klein neutrinos, we derive strong constraints on the parameters of the theory that originates from the non-observation of flavour-violating and universality-breaking phenomena. In this theory we propose a four-neutrino model which can reconcile the existing data coming from underground experiments in terms of neutrino oscillations, together with the hint from the LSND experiment and a possible neutrino contribution to the hot dark matter of the Universe.Comment: 5 pages, Talk given at the EuroConference on Frontiers in Particle Astrophysics and Cosmology, San Feliu de Guixols, Spain, 30 September - 5 October, 200

e^+ e^- --> {tilde t}_1 {tilde t}_1^* (H_1) in the MSSM with explicit CP violations

The author considers the effects of the CP-violating phases, e. g. arg(A_t) and arg(mu) on the e^+ e^- --> {tilde t}_1 {tilde t}_1^* (H_1) processes. The third generation squark trilinear terms give significant contributions to the Higgs potential at the one-loop level. This results in the changes of the stop masses and the lighter stop - the lighter anti-stop - the lightest Higgs coupling. The author shows the coupling and the loop effects on the processes. And the author will discuss the determination method of soft parameters.Comment: 18 pages, 7 figures. Detailed comments and minor changes added; To appear in Phys. Lett.

Charged LFV in a low-scale seesaw mSUGRA model

We investigate the influence of the boundary conditions of minimal supergravity (mSUGRA) on the supersymmetric mechanism for lepton flavour violation (LFV) proposed recently [1], within the framework of the MSSM extended by TeV-scale singlet heavy neutrinos. We find that the consideration of the mSUGRA boundary condition may increase the branching ratios of the muon and tauon decaying into three charged leptons by up to a factor of 5, whereas the corresponding branching ratio for their photonic decays remains almost unchanged.Comment: 6 pages, 3 figures. Prepared for the Proceedings of the 11th International Workshop on Tau Lepton Physics, Manchester, UK, September 13-17, 2010. Presented by A. Ilakova

Thermal field theory to all orders in gradient expansion

We present a new perturbative formulation of non-equilibrium thermal field theory, based upon non-homogeneous free propagators and time-dependent vertices. The resulting time-dependent diagrammatic perturbation series are free of pinch singularities without the need for quasi-particle approximation or effective resummation of finite widths. After arriving at a physically meaningful definition of particle number densities, we derive master time evolution equations for statistical distribution functions, which are valid to all orders in perturbation theory and all orders in a gradient expansion. For a scalar model, we make a loopwise truncation of these evolution equations, whilst still capturing fast transient behaviour, which is found to be dominated by energy-violating processes, leading to non-Markovian evolution of memory effects.Comment: 8 pages, 4 figures. Prepared for the proceedings of DISCRETE2012: the Third Symposium on Prospects in the Physics of Discrete Symmetries, IST Lisbon, to appear in the Journal of Physics: Conference Series (JPCS). Presented by P. Millingto

F_D-Term Hybrid Inflation with Electroweak-Scale Lepton Number Violation

We study F-term hybrid inflation in a novel supersymmetric extension of the SM with a subdominant Fayet-Iliopoulos D-term. We call this particular form of inflation, in short, F_D-term hybrid inflation. The proposed model ties the mu-parameter of the MSSM to an SO(3)-symmetric Majorana mass m_N, through the vacuum expectation value of the inflaton field. The late decays of the ultraheavy particles associated with the extra U(1) gauge group, which are abundantly produced during the preheating epoch, could lower the reheat temperature even up to 1 TeV, thereby avoiding the gravitino overproduction problem. The baryon asymmetry in the Universe can be explained by thermal electroweak-scale resonant leptogenesis, in a way independent of any pre-existing lepton- or baryon-number abundance. Further cosmological and particle-physics implications of the F_D-term hybrid model are briefly discussed.Comment: 20 pages, 1 eps figure, comments added to conclusion