Demonstration of Parity Nonconservation in Hyperon Decay

In Fig. 1 are presented two curves of the cross section versus energy which correspond adequately to the data. Curve A is similar to the curve used by Anderson, Davidon, and Kruse. ' Curve 8 begins to rise more rapidly near 100 Mev, which may be attributed to the influence of some of the p waves. It should be noted that the difference between curves A and 8 is permitted chief by the data near 100 Mev, which has a large experimental error. Curve 8 also has a somewhat larger maximum than Curve A. The important eBect is the substantially greater slope of 8 over A in the region near 150 Mev, where the previous analysis had achieved a very poor fit. A similar variation is possible in the curve of the positive-pion total cross section, but the dispersion relation for forward scattering of negative pions is not sensitive to this. For higher energies than 350 Mev we use the values indicated by reference 1. In Fig. 2 the forward scattering resulting from Curve A is plotted for f'=0 04 and f.'=0.08. The result is similar to that of reference 1. We have added the experimental value of the forward scattering at 307 Mev, which is now available. 4 In Fig. 3 the forward scattering resulting from Curve 8 is plotted for f'=0.07 and f'=0.08. Both of these 40 80 I)0 IQ 200 240 2)0 3/0 3&70 4'