ABSTRACT
Abstract. In the first part of this paper I review the construction of the realistic free fermionic models, as well as current attempts to study aspects of these models in the nonperturbative framework of M-and F-theories, I discuss the recent demonstration of a Minimal Superstring Standard Model, which contains in the observable sector, below the string scale, solely the MSSM charged spectrum, and provides further support to the assertion that the true string vacuum is connected to the Z2 x Z2 orbifold in the vicinity of the free fermionic point in the Narain moduli space. In the second part I review the recent formulation of quantum mechanics from an equivalence postulate, which offers a new perspective on the synthesis of gravity and quantum mechanics, and contemplate possible relations with string theory and beyond,
1. Introduction
Superstring phenomenology aims at achieving two goals. The first task is to reproduce the phenomenological data provided by the Standard Particle Model. The subsequent goal is to extract possible experimental signatures which may provide further evidence for the validity of specific string models, in particular, and for string theory, in general. One should however note that, in the lack of substantial experimental evidence for any extension of the Standard Model, the conservative approach would be to derive solely the Standard Model, which we may assume to include non-vanishing neutrino masses. Experimental signatures beyond the Standard Model become
firm theoretical predictions once the first goal is achieved and it appears that something extra unavoidably remains.
