Infrared divergence on the light-front and dynamical Higgs mechanism
  Dynamical Higgs mechanism on the light-front (LF) is studied using a (1+1) dimensional model, with emphasis on the infrared divergence problem. The consideration of the zero mode $ k^+ = 0 $ is not sufficient for investigating dynamical symmetry breaking on the LF. It also needs to treat properly an infrared divergence caused by internal momentum $ p^+ \to 0 ~ (p^+ \neq 0) $ in the continuum limit. In order to avoid the divergence, we introduce an infrared cutoff function $ F_{\rm IR} (p, \Lambda) $ which is not Lorentz invariant. It is then shown that the gauge boson obtains mass dynamically on the LF. 
S.Maedan (Tokyo Nat. Coll.)