A coupled channel model of scattering with SO(3,1) symmetry

An exactly solvable coupled channel scattering problem with SO(3, 1) symmet ry is presented describing the helicity scattering of a particle with spin s. It is shown that the coupled channel wavefunction is a matrix-valued fun ction with definite group theoretical properties. The scattering phase shif ts are calculated for the special values of s = (1)/(2), 1 and (3)/(2) and the result for general s is conjectured. It is also demonstrated that for a n algebraic description of this coupled channel problem both of the indepen dent Casimir operators are needed.