INSTANTONS AT ANGLES

We interpret a class of 4k-dimensional instanton solutions found by Wa rd, Corrigan, Goddard and Kent as four-dimensional instantons at angle s. The superposition of each pair of four-dimensional instantons is as sociated with four angles which depend on some of the ADHM parameters. All these solutions are associated with the group Sp(k) and are examp les of Hermitian-Einstein connections on E-4k. We show that the eight- dimensional solutions preserve 3/16 of the ten-dimensional N = 1 super symmetry. We argue that under the correspondence between the BPS state s of Yang-Mills theory and those of M-theory that arises in the contex t of Matrix models, the instantons at angles configuration corresponds to the longitudinal intersecting 5-branes on a string at angles confi guration of M-theory. (C) 1998 Elsevier Science B.V.