Testing Neutrino Parameters at Future Accelerators

The simplest unified extension of the Minimal Supersymmetric Standard Model with bilinear R--Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies.Despite the smallness of neutrino masses R-parity violation is observable at present and future high-energy colliders, providing an unambiguous cross-check of the model.Comment: 9 pages, 10 Figures in Postscript, uses ws-procs9x6.cls. Talk given at the 4th International Workshop on New Worlds in Astroparticle Physics, Faro, Portugal, 5-7 September 200

A viable A4A_4 3HDM theory of quark mass matrices

It is known that a three Higgs doublet model (3HDM)symmetric under an exact $A_4$ symmetry is not compatible with nonzero quark masses and/or non-block-diagonal CKM matrix. We show that a 3HDM with softly broken $A_4$ terms in the scalar potential does allow for a fit of quark mass matrices. Moreover, the result is consistent with $m_h=125\textrm{GeV}$ and the $h \rightarrow WW, ZZ$ signal. We also checked numerically that, for each point that passes all the constraints, the minimum is a global minimum of the potential.Comment: 21 pages, 10 Figures in PDF. Minor changes; matches version to be publishe

Minimal Supergravity with R-Parity Breaking

We show that the minimal R-parity breaking model characterized by an effective bilinear violation of R-parity in the superpotential is consistent with minimal N=1 supergravity unification with radiative breaking of the electroweak symmetry and universal scalar and gaugino masses. This one-parameter extension of the MSSM-SUGRA model provides therefore the simplest reference model for the breaking of R-parity and constitutes a consistent truncation of the complete dynamical models with spontaneous R-parity breaking proposed previously. We comment on the lowest-lying CP-even Higgs boson mass and discuss its minimal N=1 supergravity limit, determine the ranges of $\tan\beta$ and bottom quark Yukawa couplings allowed in the model, as well as the relation between the tau neutrino mass and the bilinear R-parity violating parameter.Comment: 22 pages including 4 figures, Latex. A numerical error is corrected which changes figure number 4. The rest of the paper stays the sam

Fingerprinting the Type-Z three Higgs doublet models

There has been great interest in a model with three Higgs doublets in which fermions with a particular charge couple to a single and distinct Higgs field. We study the phenomenological differences between the two common incarnations of this so-called Type-Z 3HDM. We point out that the differences between the two models arise from the scalar potential only. Thus we focus on observables that involve the scalar self-couplings. We find it difficult to uncover features that can uniquely set apart the $Z_3$ variant of the model. However, by studying the dependence of the trilinear Higgs couplings on the nonstandard masses, we have been able to isolate some of the exclusive indicators for the $Z_2\times Z_2$ version of the Type-Z 3HDM. This highlights the importance of precision measurements of the trilinear Higgs couplings.Comment: 15 pages, 4 captioned figure