Typically in unified theories the neutrino mixing angles, like the Cabibbo-Kobayashi-Maskawa (CKM) angles of the quarks, are related to the small mass ratios between fermions of different generationsâ€¦ (More)

We present a predictive scheme for fermion masses and mixings inspired by supersymmetric SO(10) in which the gauge hierarchy problem is resolved without fine tuning the parameters. There are sixâ€¦ (More)

A small neutrino Majorana mass can arise in the Standard Model as an effective dimension 5 operator. We calculate the renormalization of this operator in the minimal Standard Model and in itsâ€¦ (More)

During 2004, four divisions of the American Physical Society commissioned a study of neutrino physics to take stock of where the field is at the moment and where it is going in the near and farâ€¦ (More)

We show that in supersymmetric unified theories such as SO(10), implementation of the seeâ€“saw mechanism for neutrino masses introduces a new set of color triplet fields and thereby a new source of dâ€¦ (More)

The discrete non-Abelian symmetry A4, valid at some high-energy scale, naturally leads to degenerate neutrino masses, without spoiling the hierarchy of charged-lepton masses. Realistic neutrino massâ€¦ (More)

The commonly accepted notion of a weak unified coupling Î±X â‰ˆ 0.04, based on the assumption of the MSSMâ€“spectrum, is questioned. It is suggested that the fourâ€“dimensional unified string couplingâ€¦ (More)

We discuss experimental implications of extending the gauge structure of the Standard Model to include an additional U(1) interaction broken at or near the weak scale. We work with the most general,â€¦ (More)