Line reversal, SU$_{3}, and exchange degeneracy in K$\pm$N charge exchange at 4 GeV/c

The recent data on charge exchange reactions K/sup +/n to K/sup 0/p and K/sup -/p to K/sup 0/n are discussed. The data are shown to be consistent with SU/sub 3/ octet symmetry for helicity flip rho and A /sub 2/ quantum-number exchange. The sizeable breaking of line reversal symmetry is not consistent with the standard model which blames the s-channel helicity-non flip amplitude, while supposing that the flip amplitude is EXD and Regge pole like. A model of alpha broken EXD poles may work for the flip amplitude. (20 refs).