TEV SCALE SUPERSTRING AND EXTRA DIMENSIONS - ART. NO. 106007

Utilizing the idea of extra large dimensions, it has been suggested th at the gauge and gravity couplings unification can happen at a scale a s low as 1 TeV. In this paper, we explore this phenomenological possib ility within string theory. In particular, we discuss how the proton d ecay bound can be satisfied in type I string theory. The string pictur e also suggests different scenarios of gauge and gravitational couplin gs unification. The various scenarios are explicitly illustrated with a specific 4-dimensional N = 1 supersymmetric chiral type I string mod el with Pati-Salam-like gauge symmetry and 3 fermion families. We poin t out certain features that should be generic in other type I strings. [S0556-2821(98)00522-0].