We study the breaking of supersymmetry and its transmission to the light states in the context of the minimal SU(5) grand unified theory, with no additional singlets. This simple theory can be taken as a prototype for a program of breaking simultaneously grand unified symmetry and supersymmetry. The main predictions are: (i) d=6 proton decay is completely negligible and d=5 is in accord with ex...

Recently, a grand unification scenario in unphysical world has been proposed.1) The basic idea is as follows. Fields form multiplets under a unified gauge group and the gauge coupling unification originates from the gauge symmetry at a high-energy scale, as ordinary grand unified theories (GUTs).2), 3) Some members in multiples, however, are unphysical degrees of freedom, which are eliminated b...

The outstanding question of string theory is whether it describes our universe. This question turns out to be very difficult to answer as the space of classical string vacua has a very large degeneracy, and there lack objective criteria that would select a particular string vacuum among the numerous possibilities. One might expect non-perturbative string dynamics to lift, partially or completel...

The low energy effective action of string theory depends strongly on the process of compactification and the localization of fields in extra dimensions. Explicit string constructions towards the minimal supersymmetric standard model (MSSM) reveal interesting results leading to the concept of local grand unification. Properties of the MSSM indicate that we might live at a special location close ...

At 15, Ron Germain cared for white mice kept on a ping-pong table in his basement. " You couldn't just buy inbred mice at the pet store, " he recalls, " but I had a connection. " With his C57BL/6 and A/J strains, he attempted to cure graft-versus-host disease with thymic transplants. His mother would supplement these experiments by driving him to Rockefeller University, where the young Germain ...

The geological record indicates that the major animal phyla began biomineralizing in a relatively short interval of time during the Cambrian evolutionary explosion, about 525 Myr ago. Because these phyla diverged well before this biomineralization event, it was triggered either by an unprecedented lateral genetic transfer, or was the result of parallel exaptation of an ancestral biomineral syst...