SEESAW SCALES AND STEPS FROM THE STANDARD MODEL TOWARDS SUPERSTRING-INSPIRED FLIPPED E6

Abstract

Recently in connection with superstring theory and with an alternative nonsupersymmetric "Exceptionally Simple Theory of Everything," E8 and E6 unifications became very promising. In the present paper we have investigated a number of available paths from the Standard Model (SM) to the E6 unification, considering chains of flipped models following the extension of the SM, also a chain with a left–right symmetry. We have presented four examples including nonsupersymmetric and supersymmetric extensions of the SM and different contents of the Higgs bosons providing the breaking of the flipped SO(10) and SU(5) down to the SM. It was shown that the final unification E6× U (1) or E6 at the (Planck) GUT scale M SSG depends on the number of the Higgs boson representations considered in theory.