1. M. Schwartz: private communication; andL. I. Schiff: private communication, both suggested such experiments to the authors some time ago. Such ideas have undoubtedly been considered by many others as well. As electron and neutrino induced weak interactions are very similar much of the discussion of such points as time-reversal violation, PCAC, and Cabibbo theory can be found in discussions of neutrino interactions as for example those of ref. (2). We review these points here for purposes of completeness. To our knowledge however there does not exist in the literature a numerical analysis of electron induced processes or results analogous to those we give in Fig. 1 and 2 or in Tables I and II.
2. For example see the following and references cited therein:A. Fujii andY. Yamaguchi:Nuovo Cimento,43 A, 325 (1966);N. Cabibbo andF. Chilton:Phys. Rev.,137, B 1628 (1965);S. M. Berman andM. Veltman:Phys. Lett.,12, 275 (1964);S. Adler:Nuovo Cimento,30, 1020 (1963), erratum,32, 509 (1964);J. S. Bell andS. M. Berman:Nuovo Cimento,25, 404 (1962);T. D. Lee andC. N. Yang:Phys. Rev.,126, 2239 (1962);N. Cabibbo andR. Gatto:Nuovo Cimento,15, 304 (1960).
3. R. P. Feynman andM. Gell-Mann:Phys. Rev.,109, 193 (1958);E. C. G. Sudarshan andR. E. Marshak:Proceedings of the Padua-Venice Conference on Mesons and Recently Discovered Particles, 1957 (Padua-Venice, 1958);Phys. Rev.,109, 1860 (1958).
4. N. Brene, L. Veje, M. Roos andC. Cronstrom:Phys. Rev.,149, 1288 (1966).
5. The notation for Dirac spinors, etc., is that ofJ. D. Bjorken andS. D. Drell:Relativistic Quantum Mechanics (New York, 1964).