D-branes in non-critical superstrings and minimal super-Yang-Mills in various dimensions

We construct and analyze D-branes in superstring theories in even dimensions less than ten. The backgrounds under study are supersymmetric Rd-1.1 x SL (2, R)(k)/U (1) where the level of the supercoset is tuned such as to provide bona fide string theory backgrounds. We provide exact boundary states for D-branes that are localized at the tip of the cigar SL(2, R)/U (1) supercoset conformal field theory. We analyze the spectra of open strings on these D-branes and show explicitly that they are consistent with supersymmetty in d = 2, 4 and 6. The low energy theory on the world-volume of the D-brane in each case is pure Yang-Mills theory with minimal supersymmetry. In the case with four macroscopic flat directions d = 4, we realize an N = 1 super-Yang-Mills theory, and we interpret the backreaction for the dilaton as the running of the gauge coupling, and study the relation between R-symmetry breaking in the gauge theory and the backreaction on the RR axion. (c) 2006 Elsevier B.V. All rights reserved.