TWISTED QUANTUM AFFINE SUPERALGEBRA U-Q[SL(2 2)((2))], U-Q[OSP(2/2)] INVARIANT R-MATRICES AND A NEW INTEGRABLE ELECTRONIC MODEL/

We describe the twisted affine superalgebra sl(2\2)((2)) and its quant ized version U-q[sl(2\2)((2))]. We investigate the tensor product repr esentation of the four-dimensional grade star representation for the f ixed-point sub superalgebra U-q[osp(2\2)]. We work out the tensor prod uct decomposition explicitly and find that the decomposition is not co mpletely reducible. Associated with this four-dimensional grade star r epresentation we derive two U-q[osp(2\2)] invariant R-matrices: one of them corresponds to U-q [sl(2\2)(2)] and the other to U-q [osp(2\2)(( 1))]. Using the R-matrix for U-q[sl(2\2)((2))], we construct a new U-q [osp(2\2)] invariant strongly correlated electronic model, which is in tegrable in one dimension. Interestingly this model reduces in the q = 1 limit, to the one proposed by Essler et al which has a larger sl(2\ 2) symmetry.