On soft breaking and CP phases in the supersymmetric standard model

We consider a class of N=1 supersymmetric extensions of the Standard Model in which the soft breaking sector is CP conserving at the GUT scale. We study the question of whether the presence of explicit CP violation in the Yukawa sector of the theory induces through renormalization effects CP violating phases in the soft terms, which could lead to observable effects. A clear pattern appears in the structure of phases in the soft sector. In particular, the inclusion of intergenerational mixing induces large phases in the flavour mixing entries of the trilinear soft breaking terms, whereas the diagonal entries remain real. A mechanism is proposed for generating through chargino exchange a contribution to the neutron electric dipole moment which can be a few orders of magnitude larger that that of the Standard Model, although still out of reach of experimental tests. We comment on the possible relevance of these phases for baryogenesis at the weak scale in minimal supersymetric scenarios, recently considered in the literature.Comment: 12 pages + 1 figure (postscript file available on request), LATEX, SISSA 173/93/E

Using supernova neutrinos to monitor the collapse, to search for gravity waves and to probe neutrino masses

We discuss the importance of observing supernova neutrinos. By analyzing the SN1987A observations of Kamiokande-II, IMB and Baksan, we show that they provide a 2.5{\sigma} support to the standard scenario for the explosion. We discuss in this context the use of neutrinos as trigger for the search of the gravity wave impulsive emission. We derive a bound on the neutrino mass using the SN1987A data and argue, using simulated data, that a future galactic supernova could probe the sub-eV region.Comment: 8 pages, 1 figure. Proceeding for the Galileo-Xu Guangqi meeting: The Sun, the Stars, the Universe and General Relativity; October 26-30, 2009, Shanghai (China). Accepted for publication at International Journal of Modern Physics

Atmospheric neutrinos in a Large Liquid Argon detector

In view of the evaluation of the physics goals of a large Liquid Argon TPC, evolving from the ICARUS technology, we have studied the possibility of performing precision measurements on atmospheric neutrinos. For this purpose we have improved existing Monte Carlo neutrino event generators based on FLUKA and NUX by including the 3-flavor oscillation formalism and the numerical treatment of Earth matter effects. By means of these tools we have studied the sensitivity in the measurement of Theta(23) through the accurate measurement of electron neutrinos. The updated values for Delta m^2(23) from Super-Kamiokande and the mixing parameters as obtained by solar and KamLand experiments have been used as reference input, while different values of Theta(13) have been considered. An exposure larger than 500 kton yr seems necessary in order to achieve a significant result, provided that the present knowledge of systematic uncertainties is largely improved.Comment: Talk given at the worksgop "Cryogenic Liquid Detectors for Future Particle Physics", LNGS (Italy) March 13th-14th, 200

Fermion Mass Hierarchy in Lifshitz Type Gauge Theory

We study the origin of fermion mass hierarchy and flavor mixing in a Lifshitz type extension of the standard model including an extra scalar field. We show that the hierarchical structure can originate from renormalizable interactions. In contrast to the Froggatt-Nielsen mechanism, the higher the dimension of associated operators, the heavier the fermion masses. Tiny masses for left-handed neutrinos are obtained without introducing right-handed neutrinos.Comment: 13 pages; clarifications of some point