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 (ēe) (-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=GF=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. © 1975 Plenum Publishing Corporation.