Phenomenological constraints on supergravity models

Minimal supergravity models are characterized by five free parameters. The author has calculated the low-energy effective lagrangian by a full, analytic solution of the renormalization group equations at the one-loop level, in terms of the five parameters. He studies the constraints obtained from the requirement of SU(2) x U(1) breaking, and obtain the allowed domains for four parameters. However, the so-defined regions have a very strong dependence on the unknown t-quark mass. The author has also estimated the contribution of gluino exchange to the dipole electric moment of the neutron (this is a new, unpublished result). It is proportional to the relative phase between the parameter A and the gluino mass. He assumes that this phase only originates from the Kobayashi-Maskawa phase through radiative corrections. The result turns out to be much smaller than the experimental upper bound, in strong disagreement with other recent evaluations