Threshold effects on the mass-scale predictions in SO(10) models and solar-neutrino puzzle

B-L violating proton decay modes and new baryogenesis scenario in SO(10)

We show that grand unified theories based on SO(10) generate quite naturally baryon number violating dimension seven operators that violate B-L, and lead to novel nucleon decay modes such as n→e(-)K(+), e(-)π(+) and p→νπ(+). We find that in two-step breaking schemes of nonsupersymmetric SO(10), the partial lifetimes for these modes can be within reach of experiments. The interactions responsible for these decay modes also provide a new way to understand the origin of matter in the Universe via the decays of grand unified theory (GUT) scale scalar bosons of SO(10). Their (B-L)-violating nature guarantees that the GUT scale induced baryon asymmetry is not washed out by the electroweak sphaleron interactions. In minimal SO(10) models this asymmetry is closely tied to the masses of quarks, leptons and the neutrinos.

Supersymmetry facing experiment: much ado (already) about nothing (yet)

This report emphasizes the comparison between supersymmetric models and experiments. A minimal theoretical introduction is included as a guide to the interpretation of results. The existing constraints from low energy measurements, accelerator searches (LEP, Tevatron and HERA) and non-accelerator searches for neutralinos are presented. Prospects for upgrades of these facilities and for the LHC and linear collider are summarized. Most discussions are made in the framework of the minimal supersymmetric standard model inspired by supergravity (MSUGRA). But alternatives such as gauge mediated supersymmetry breaking (GMSB), anomaly mediated supersymmetry breaking (AMSB), models with R-parity violation and even alternatives to supersymmetry are also briefly considered.