A natural solution to the μ-problem in supergravity theories

Abstract

We propose a “natural” way to avoid the introduction by hand of a small mass scale μ in the observable sector of N = 1 supergravity theories. In our approach, μ automatically arises from the general couplings of broken supergravity. In this way, all low energy mass parameters arise only from supergravity breaking and, in particular, SU (2) × U (1) is left unbroken in the limit of exact supersymmetry. Our solution of the μ-problem presents interesting connections with the strong CP puzzle through the implementation of symmetriesàla Peccei and Quinn.