N = 1 supergravity, the weak scale and the low-energy particle spectrum

Abstract

We consider in detail the radiative SU(2) × U(1) breaking induced by broken N = 1 supergravity. We include in this study some parameters (b-quark Yukawas, mixed Higgs mass terms) neglected in a previous analysis. We show that there are essentially two types of mechanisms leading to radiative SU(2) × U(1) breaking. The first of them occurs for a t-quarks mass m t ⪆60 GeV. The second one appears for arbitrary small values of m t (without using a large A). These two mechanism correspond to two different classes of local SUSY GUTs. We present results for the low-energy supersymmetric particle spectrum. In some of the possible scenarios presented, squarks, sleptons and/or gauginos are accessible to present accelerator energies. In other scenarios, the scalar neutrinos may be the lightest R-odd particles. We finally remark that the SU(5) prediction for m b/ m t is substanially suppressed for a heavy t-quark.