A multi-scale perturbative approach to SU(2)-Higgs classical dynamics:   stability of nonlinear plane waves and bounds of the Higgs field mass
  We study the classical dynamics of SU(2)-Higgs field theory using multiple scale perturbation theory. In the spontaneously broken phase, assuming small perturbations of the Higgs field around its vacuum expectation value, we derive a nonlinear Schroedinger equation and study the stability of its nonlinear plane wave solutions. The latter, turn out to be stable only if the Higgs amplitude is an order of magnitude smaller than that of the gauge field. In this case, the Higgs field mass possesses some bounds which may be relevant to the search for the Higgs particle at ongoing experiments. 
V. Achilleos, F.K. Diakonos, D.J. Frantzeskakis, G.C. Katsimiga, X.N.   Maintas, C.E. Tsagkarakis and A. Tsapalis
hep-ph