BOUND-STATE-SPECTRUM OF THE SU(2) MASSIVE THIRRING MODEL

We present the bound-state spectrum of an SU(2) massive Thirring model by employing the 1/K expansion method. For charge-2 sector (qq), the model is found to possess one bound state. For charge-0 sector (qqBAR boson), there are four bound states, one singlet and three triplet bos ons. For various combinations of U(1) and SU(2) coupling constants g(s ) and g(v), we find some interesting observations. For g(s) = 0, for e xample, the binding energy of the triplet boson vanishes again when g( v) is 4pi, which shows a critical point. Also, the charge-2 state and the singlet boson have the same mass spectrum behaviour. For g(v) = 4/ 3g(s), we find that the charge-2 sector does not have a bound state wh ile the singlet and triplet bosons become just the same boson as the U (1) case. It is still open to interpretation whether these phenomena s hould be treated in terms of Abelian and/or non-Abelian bosonizations.