Determining See-Saw Parameters from Weak Scale Measurements?

The see-saw mechanism is a very attractive explanation for small neutrino masses, parametrized at the GUT scale by the right-handed Majorana mass matrix, ${\cal M}$, and the neutrino Yukawa matrix, ${\bf Y_\nu}$. We show that in a SUSY model with universal soft terms, ${\cal M}$ and ${\bf Y_\nu}$ can be calculated from the light neutrino masses, the MNS matrix, and ${\bf Y^{\dagger}_\nu} {\bf Y_\nu}$, which enters into the left-handed slepton radiative corrections. This suggests that in principle the GUT-scale inputs of the seesaw could be reconstructed from the neutrino and sneutrino mass matrices. We briefly discuss why this is impractical, but advocate the neutrino and sneutrino mass matrices as an alternative bottom-up parametrization of the seesaw.Comment: Version to be published. References added, modified abstract, minor stylistic changes. Content unchange

Spaghetti Regionalism or Strategic Foreign Trade: Some Evidence for Mexico

After signing ten free trade agreements between 1993 and 2001, Mexico as a world leader in foreign trade policy continues to negotiate with countries such as Japan, Panama, Uruguay or Argentina. Criticism of multiple regional trade agreements (RTAs) arises from a consistency test, but also from the ability of a country to administer them. Mexico's multiple agreements have generally used the principle of NAFTA consistency, after the acceptance that NAFTA became a broader and deeper accord than results of the Uruguay multilateral achievements. An analysis of multiple RTAs is presented, including a game model of equilibrium, along with a political economy approach of why Mexico seeks multiple RTAs as its foreign trade policy.

Lepton parameters in the see-saw model extended by one extra Higgs doublet

We investigate the radiative generation of lepton masses and mixing angles in the Standard Model extended by one right-handed neutrino and one extra Higgs doublet. We assume approximate rank-1 Yukawa couplings at a high energy scale and we calculate the one loop corrected charged lepton and neutrino mass matrices at the low energy scale. We find that quantum effects generate, for typical high energy parameters, a hierarchy between the muon and the tau mass, a hierarchy between the solar and the atmospheric mass splittings, and a pattern of leptonic mixing angles in qualitative agreement with experiments

Radiative Generation of Quark Masses and Mixing Angles in the Two Higgs Doublet Model

We present a framework to generate the quark mass hierarchies and mixing angles by extending the Standard Model with one extra Higgs doublet. The charm and strange quark masses are generated by small quantum effects, thus explaining the hierarchy between the second and third generation quark masses. All the mixing angles are also generated by small quantum effects: the Cabibbo angle is generated at zero-th order in perturbation theory, while the remaining off-diagonal entries of the Cabibbo-Kobayashi-Maskawa matrix are generated at first order, hence explaining the observed hierarchy $|V_{ub}|,|V_{cb}|\ll |V_{us}|$. The values of the radiatively generated parameters depend only logarithmically on the heavy Higgs mass, therefore this framework can be reconciled with the stringent limits on flavor violation by postulating a sufficiently large new physics scale.Comment: To appear in Physics Letters