Ashoke Sen

We analyze M-theory compactified on (K3 × S)/Z2 where the Z2 changes the sign of the three form gauge field, acts on S as a parity transformation and on K3 as an involution with eight fixed points preserving SU(2) holonomy. At a generic point in the moduli space the resulting theory has as its low energy limit N = 1 supergravity theory in six dimensions with eight vector, nine tensor and twenty hypermultiplets. The gauge symmetry can be enhanced (e.g. to E8) at special points in the moduli space. At other special points in the moduli space tensionless strings appear in the theory. On leave of absence from Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay 400005, INDIA E-mail: [email protected], [email protected]