Tests of time reversal invariance and their significance

Abstract

The object of this talk is to review briefly tests of time reversal invariance (TRI) in low and intermediate energy physics and to discuss their significance for the understanding of the origins of time reversal violation (TRV), or CP violation observed up to now only in neutral K decay. The main emphasis of this analysis lies on non‐weak processes for which the conclusions are rather pessimistic: In spite of the fact that in nuclei some TRV tests have reached an impressive accuracy of better than 10−3 it is hard if not impossible to extract a significant restriction on a basic time reversal violating interaction from upper limits in this field. In the last section I shall come back to a recent TRI test in nuclear β‐decay for which prospects are not as bad.