On the Solution of the Polonyi Problem with No-Scale Type Supergravity

We study the solution to the Polonyi problem in the framework of no-scaletype supergravity. In such a model, Polonyi field can weigh as $O(10{\rm TeV})$and decay just before the big-bang nucleosynthesis. It is shown that in spiteof a large entropy production by the decay of the Polonyi field, one cannaturally explain the present value of the baryon-to-entropy ratio, $n_B/s \sim(10^{-10}-10^{-11})$ if the Affleck-Dine mechanism for baryogenesis works. Itis pointed out, however, that there is another cosmological problem related tothe abundance of the lightest superparticles produced by the decay of thePolonyi field.Comment: Talk given at the Yukawa International Seminar '95 in Kyoto, 21 - 26 August, 199