The contributions are divided into two parts. The first deals with the problem of the convergence of the three fundamental forces of nature measured by the gauge couplings, with the onset of the energy threshold for the production of the lightest supersymmetric particles and with the existence of a gap between the string scale and the GUT scale. The second deals with the study of a theoretical model capable of including supersymmetry with the minimum number of parameters (possibly one), and agreeing with all the conditions established by string theories — this turns out to be a “one-parameter no-scale supergravity” model whose experimental consequences are investigated for present and future facilities aimed at the discovery of the first example of the superparticle.

Sergio Ferrara and Michael Duff, two of the founders of supergravity, superstring and M-theories, introduce the fascinating subject of supersymmetry, superspace and the superworld; the presentation of the seminal papers by Zichichi and his collaborators is made by two eminent physicists: Rudolf Mössbauer and Sergio Ferrara.
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