SCALAR-GAUGE DYNAMICS IN (2-DIMENSIONS AT SMALL AND LARGE SCALAR COUPLINGS(1))

We present the results of a detailed calculation of the excitation spe ctrum of states with quantum numbers J(PC) = 0(++), 1(-- an)d 2(++) in the three-dimensional SU(2) Higgs model at two values of the scalar s elf-coupling and for fixed gauge coupling, We study the properties of Polyakov loop operators, which serve to test the confining properties of the model in the symmetric phase. At both values of the scalar coup ling we obtain masses of bound states consisting entirely of gauge deg rees of freedom (glueballs), which are very close to those obtained in the pure gauge theory. We conclude that the previously observed, appr oximate decoupling of the scalar and gauge sectors of the theory persi sts at large scalar couplings. We study the crossover region at large scalar coupling and present a scenario how the confining properties of the model in the symmetric phase are lost inside the crossover by mea ns of flux tube decay. We conclude that. the underlying dynamics respo nsible for the observed dense spectrum of states in the Higgs region a t large couplings must be different from that in the symmetric phase. (C) 1998 Elsevier Science B.V.