Pseudo-Dirac Solar Neutrinos

Three of the viable solutions of the solar neutrino problem are consistent with close to maximal leptonic mixing: $\sin^2\theta_{12}={1\over2}(1-\epsilon_{12})$ with $|\epsilon_{12}|\ll1$. Flavor models can naturally explain close to maximal mixing if approximate horizontal symmetries force a pseudo-Dirac structure on the neutrino mass matrix. An experimental determination of $|\epsilon_{12}|$ and sign($\epsilon_{12}$) can constrain the structure of the lepton mass matrices and consequently provide stringent tests of such flavor models. If both $|\epsilon_{12}|$ and $\Delta m^2_{21}$ are known, it may be possible to estimate the mass scale of the pseudo-Dirac neutrinos. Radiative corrections to close to maximal mixing are negligible. Subtleties related to the kinetic terms in Froggatt-Nielsen models are clarified.Comment: 24 pages; v3: significant improvements and modifications, particularly in the three generation analysi

CP violation in meson decays

This is a written version of a series of lectures aimed at graduate students in the field of (theoretical and experimental) high energy physics. The main topics covered are: (i) The flavor sector of the Standard Model and the Kobayashi-Maskawa mechanism of CP violation; (ii) Formalism and theoretical interpretation of CP violation in meson decays; (iii) K decays; (iv) D decays; (v) B decays: b -> c c-bar s, b -> s s-bar s, b -> u u-bar d and b -> c u-bar s, u c-bar s; (vi) CP violation as a probe of new physics and, in particular, of supersymmetry.Comment: 67 pages, 7 figures; Lectures given at the `Third CERN-CLAF School of High Energy Physics', Malargue (Argentina) 3/2005, and at the Les Houches Summer School (Session LXXXIV) on `Particle Physics Beyond the Standard Model,' Les Houches (France) 8/200