Critical Behavior of a General O(n)-symmetric Model of two n-Vector   Fields in D=4-2 epsilon
  The critical behaviour of the O(n)-symmetric model with two n-vector fields is studied within the field-theoretical renormalization group approach in a D=4-2 epsilon expansion. Depending on the coupling constants the beta-functions, fixed points and critical exponents are calculated up to the one- and two-loop order, resp. (eta in two- and three-loop order). Continuous lines of fixed points and O(n)*O(2) invariant discrete solutions were found. Apart from already known fixed points two new ones were found. One agrees in one-loop order with a known fixed point, but differs from it in two-loop order. 
Yuri M. Pis'mak (1), Alexej Weber (2), Franz J. Wegner (2) ((1)   Department of Theoretical Physics State University Saint-P...