Nucleon polarization resulting from π-meson production

In this paper we derive the polarization of the nucleons resulting from the three «fundamental,» meson-nucleon reactions π+N→N′+π′+,γ+N→N′+π′,π+D→N+N′. It is shown that the observed angular distributions of these reactions permit of two types of solutions—a «Fermi» solution, in which the important interaction is in the meson-nucleon intermediate state ofJ=3/2+,T=3/2; and a «Yang» solution, which requires a strong interaction in the stateJ=1/2+,T=3/2. These solutions can be distinguished on the basis of the polarization of the recoil nucleons. Tables are given for the predicted polarizations in the second and third of the above reactions (the first has previously been discussed byFermi). The greatest difference between the two solutions is predicted in the photoproduction of neutral mesons. However, the kinematics of the reactions are such that the most likely case for detection of the polarized nucleons is the third of the above reactions; in this case, however, the difference between the predicted polarizations for the two solutions is only in the sign.