Polarization and asymmetry of protons in an annihilation process e− + e+ → p + ¯p in the presence of weak neutral currents

The differential and total cross sections for annihilation of longitudinally polarized and transversely polarized electrons and positrons into pairs of longitudinally polarized protons and antiprotons are calculated in the center-of-mass system. The expressions obtained for the cross sections have electromagnetic, weak, and interference terms. It is shown that the existence of a weak current-current interaction (e) (¯pp) must lead for protons and antiprotons, emitted at an angle ®=90° to a nonzero degree of longitudinal polarization P(E) =1.3 and 36% for E=2.5 and 10 GeV and G=G_F=10^–5 M^–2,to the presence of forward-backward asymmetry in the angular distribution of the protons A(E)=1 and 12% for E=2.5 and 10 GeV (the asymmetry exists even when all the particles are unpolarized), and to other effects which are absent in the case of a pure electromagnetic interaction. It is shown that in experiments with polarized particles the contributions of different form factors can be distinguished and studied separately.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 93–100, January, 1974.We thank the participants in the seminars of Professor A. A. Sokolov and Professor Ya. P. Terletskii for discussions of the work.     

Effects of the finite size of a nucleus having a magnetic dipole moment on the bremsstrahlung of longitudinally polarized electrons

Expressions are obtained in the Born approximation for the differential cross section and circular polarization of the bremsstrahlung radiated by longitudinally polarized electrons in the field of a nucleus having a magnetic dipole moment. Account is taken of the rms radius and the fourth moment of the charge distribution and the magnetic moment of the nucleus. The effects of r² and r⁴ on the spectrum of the charge and magnetic bremsstrahlung are studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 97–104, September, 1969.The authors thank professor A.A. Sokolov for discussion of these results.