Tests of Conservation Laws

In keeping with the current interest in tests of conservation laws, we collect together a Table of experimental limits on all weak and electromagnetic decays, mass differences, and moments, and on a few reactions, whose observation would violate conservation laws. The Table is given only in the full Review of Particle Physics, not in the Particle Physics Booklet. For the benefit of Booklet readers, we include the best limits from the Table in the following text. Limits in this text are for CL=90% unless otherwise specified. The references for these data can be found in the the Particle Listings in the Review. A discussion of these tests follows. CP T INVARIANCE General principles of relativistic field theory require invariance under the combined transformation CP T. The simplest tests of CP T invariance are the equality of the masses and lifetimes of a particle and its antiparticle. The best test comes from the limit on the mass difference between K 0 and K 0. Any such difference contributes to the CP-violating parameter. Assuming CP T invariance, φ , the phase of should be very close to 44 •. (See the review " CP Violation in K L decay " in this edition.) In contrast, if the entire source of CP violation in K 0 decays were a K 0 − K 0 mass difference, φ would be 44 • + 90 •. Assuming that there is no other source of CP T violation than this mass difference, it is possible to deduce that[1]