Selectron pair production in e+e− colliders and the supergravity spectrum

In Minimal Supergravity, with universality of scalar and gaugino masses and radiative breaking of the electroweak symmetry, the physical spectrum depends only on a few independent parameters. This predictive power implies that a few experimental measurements may be enough to determine these parameters. In these models, selectrons are among the lightest supersymmetric particles. In a scenario where selectrons are light enough to be produced at LEP2, we show that the measurement of their mass, their production cross section, and the mass of their decay product, the lightest neutralino, can be used to determine the value of the fundamental parameters of the model, and with them, the entire supersymmetric and Higgs spectrum can be predicted. In this scenario of light selectrons we find that 65