Vacuum configurations for superstrings

We study candidate vacuum configurations in ten-dimensional O(32) and E<inf>8</inf> × E<inf>8</inf> supergravity and superstring theory that have unbroken N = 1 supersymmetry in four dimensions. This condition permits only a few possibilities, all of which have vanishing cosmological constant. In the E<inf>8</inf> × E<inf>8</inf> case, one of these possibilities leads to a model that in four dimensions has an E<inf>6</inf> gauge group with four standard generations of fermions. © 1985.