ON THE SIGN OF THE EFFECTIVE PSEUDOSCALAR TERM IN μ–CAPTURE REACTIONS

Recent experiments seem to show that the sign of the effective pseudoscalar term in μ–capture reactions is different from the theoretical result of Goldberger and Treiman based on V – A theory and dispersion relation technique. A possible explanation of this difference is proposed in the present note. It is shown that a very small p. s. tem in the HamiHonian (of the order 1/100 of the effective p. s. term) can change the sign of the effective p. s. term. If this small term is transformed and added as a part of the universal axial vector current, it will produce practically no effect in β–decay and π → μ + ν decay. Finally the inclusion of hyperon pairs is considered.