Abstract :
We study the M5-brane configuration of the chiral gauge theory whose type IIA brane configuration with an orientifold 6-plane (06) is studied by various authors. Much of thepaper is devoted to studying the related M-theory picture of SO/Sp gauge theory with fundamental flavors realized in a type IIA setup with the 06-plane. The Higgs branch of N = 2 SO/Sp gauge theory is studied and the curve corresponding to the rotated brane configuration is presented. In the chiral gauge theory, the middle NS′5-brane on top of the 06-plane is realized as a detached rational curve in M-theory. Depending on the location of the rational curve in the x7 direction, the same curve plus the rational curve can be interpreted as describing the Coulomb branch of SU(2Nc) chiral gauge theory, SO(2Nc)/Sp(Nc) gauge theory with Nf/(Nf+4) fundamental hypermultiplets. Various consistency checks for this proposal are made. By introducing two more rational curves corresponding to NS′5-branes one can produce a non-trivial fixed point which mediates chiral-non-chiral transition.
