Left-right symmetric superstring supergravity

A left-right (L-R) symmetric model of four-dimensional supergravity with SO(10) gauge group, obtained as the low-energy limit in superstring theory, is considered. The spectrum of gauge fields and their interactions agree with the Weinberg-Salam theory and the model contains additional heavy bosons WR± and Zμ'. Besides the Ng = 3 generations of 16-plets the SO(10) model includes fragments of such generations, which play the role of Higgs particles, and scalar chiral fields, whose number exceeds the number of generation by one. As a result each generation's neutrino acquires a stably small Majorana mass. It is shown that the scalar fields potential gives rise to spontaneous breaking of the SU(2)R group and the L-R symmetry, resulting in the appearance of the standard Weinberg-Salam theory in the low-energy region