CONCERNING TESTS OF TIME REVERSAL INVARIANCE VIA THE POLARIZATION-ANALYZING POWER EQUALITY

It is shown that one of the more recent tests of time reversal invariance, via measurements of the polarization and the analyzing power in p + {sup 13}C elastic scattering, does not, in fact, provide a significant test of time reversal invariance. This follows from the fact that the polarization-analyzing power equality depends on the equality of the two possible spin~flip probabilities. A possible non-zero difference between the spin-flip was beyond the precision of the experiment because the individual spin-flip probabilities are so small. It is immediately clear that tests of time reversal invariance should be made through measurements of the polarization and analyzing power in a reaction (and its inverse) where the spin-flip probability is expected or known to be large