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The departure from T invariance in neutral K-meson decays is shown to be directly demonstrable through suitable measurements. The predicted asymmetries include a CP-and T-noninvariant effect larger than any which has been measured so far. u N D E R the assumption of TCP invariance, the as IRO) will be found after a lapse of time T to have observation of KzO -+ 2n decays1 delnonstrates transformed into T noninvariance to the same extent that it demonstrates the failure of CP invariance. Tests of T invariance in Current Algebra,

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due to the pion cloud should change sign. Relativistic field theory shows on general grounds that F(k 2 ) has the form F(k 2 ) = I dm, J2m T m 2 -{-k 2 where the lower limit of integration corresponds to the threshold for pion pair creation by an external electromagnetic field. With our assumptions about p°, it is thus possible that the two form factors F and F f cancel approximately for the neutron but reinforce for the proton, in agreement with observation. If we equate tentatively the mean square radius of the proton with the one due to p°:which checks with the previous estimate since G 2 /nc would be of the order one. The decay lives become, very approximately, r o~1 0-19 -10-20 sec, r b~Tc~1 0-17 -lO" 18 sec.We can pursue further consequences of our assumption.(1) p° could be produced by any strong nuclear reactions, but it would instantly decay mostly into a high-energy 7(>140 Mev) and a p°. The ratio of charged to neutral components in high-energy reactions should accordingly be influenced.(2) The second maximum of the pion-nucleon scattering around 1 Bev 2 could be attributed to the reaction if a resonance should occur for such a system.(3) p° would contribute a repulsive nuclear force of Wigner type and short range (<0.7X10~1 3 cm), more or less similar to the phenomenological hard core.(4) The anomalous moment of the nucleon 3 should be affected by p°. The main effect seems to be that p° and the usual pion give opposite contributions to the isotopic scalar part of the core moment, thus tending to bring better agreement between theory and experiment.(5) If it is energetically possible, we ought to expect that K mesons and hyperons would sometimes decay by emitting a p°.It should perhaps be added that the neutral meson considered here is similar in nature to the one introduced by Teller for quite different purposes. 4 R ECENTLY, various experiments 1-3 established the nonconservation of parity in 0 decay, w decay, and JJL decay. The purpose of this note is to emphasize that, in view of these developments, experiments on hyperon production and decay in (w+p) collisions of the type done by various groups using bubble chambers, 4 seem now to be especially important for a clarification of the following related questions: (i) whether parity conservation is violated in hyperon decays 5 and (ii) whether parity doublets exist. 6 A detailed analysis concerning the possible detection of parity doublets exists in the literature. 6 In the following we shall make a phenomenological study of the problem of possible detection of parity nonconservation in hyperon decay under the assumption that there exist no parity doublets for either K mesons or hyperons. 7 To make the analysis unambiguous and to draw conclusions that are relatively definite, it is necessary that one knows something about the polarization of the hyperons produced. It seems that a good plan is to study hyperon production and decay near threshold.Production and decay of S~. For example, let us consider the production of 2~ from (ir~+p) collisions:Tr-+p...