In the present paper we investigate the phase transition "Coulomb--confinement" in the Higgs model of abelian scalar dyons -- particles having both, electric $e$ and magnetic $g$, charges. It is shown that by dual symmetry this theory is equivalent to scalar fields with the effective squared electric charge e^{ *2}=e^2+g^2. But the Dirac relation distinguishes the electric and magnetic charges of dyons. The following phase transition couplings are obtained in the one--loop approximation: \alpha_{ crit}=e^2_{ crit}/4\pi\approx 0.19, \tilde\alpha_{ crit}=g^2_{ crit}/4\pi\approx 1.29 and \alpha^*_{ crit}\approx 1.48.
Categories: hep-ph hep-lat hep-th