A central extension of U_q sl(2,2)⁽¹⁾ and R-matrices with a new parameter

In this paper, using a quantum superalgebra associated with the universal central extension of sl(2,2)^{(1)}, we introduce new R-matrices having an extra parameter x. As x\to 0, they become those associated with the symmetric and anti-symmetric tensor products of the copies of the vector representation of U_q sl(2,2)^{(1)}.