Lished). Violation of Cp Invariance and the Possibility of Very Weak Interactions*

section for charge exchange obtained from our data and compare it with the prediction using the forward dispersion relationships to calculate the real part and the optical theorem to calculate the imaginary part of the forward scattering amplitude. Ne used the most recent evaluation of the dispersion relation, ' based upon new Saclay measurements that have been published by Amblard et al. ,"to make the prediction. The band around the predicted curve is the estimate of the uncertainty on the smooth curve as determined in reference 9. The agreement is seen to be quite good. We would like to thank Mr. B. Dainese and his group, and Mr. Thomas Lyons and his group, for their expert assistance in the construction, development, and operation of the spark-chamber system. We would also like to thank the entire staff of the Brookhaven National Laboratory Cosmotron, without whose expert assistance and support the experiment could not have been performed. Finally, we are grateful to our respective scanning groups for their fast and efficient reduction of the data.