Two-dimensional SU(N) Higgs theory: An instanton approach

The two-dimensional non-abelian Higgs model is studied by employing a dilute gas of Z_N vortices. The results obtained are similar to the corresponding results of the abelian model, studied by Callan, Dashen and Gross, and Raby and Ukawa. The most interesting conclusion is that in the presence of some number, N_F, of massless fermion flavors, the theory behaves differently for N > N_crit or N < N_crit where N_crit = N_F/(N_F?2).