A natural solution to the μ-problem in supergravity theories

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)xU(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 symmetries a la Peccei and Quinn. (orig.)