M theory fivebrane interpretation for strong coupling dynamics of SO(N_c) gauge theories

We study M theory fivebranes to understand the moduli space of vacua of N = 1 supersymmetric SO(N_c) gauge theory with N_f flavors in four dimensions. We discuss how the various branches of this theory arise in the string/M theory brane configurations and compare our results with the ones obtained earlier by Intriligator and Seiberg in the context of field theory. In the M theory approach, we explain the various branches from the asymptotic position of semi-infinite D4 branes in the w = x⁸ + ix⁹ direction, which is closely related to the eigenvalues of the meson matrix M^ij = Qⁱ_aQ^j_a where Qⁱ_a is a squark multiplet(i = 1, ⋯ ,2N_f and a = 1, ⋯, N_c). In M theory, these branches are explained by observing a new phenomena which did not occur for the gauge groups SU(N_c) or Sp(N_c).