Angular distributions in the decays of the triplet D2 state of charmonium directly produced in polarized proton-antiproton collisions

A. W. K. Mok, Hong Kong Baptist University
K. J. Sebastian


Using the helicity formalism, we calculate the combined angular distribution function of the two gamma photons and the electron in the cascade process pp → 3D2 → χJ+γ1 → (ψ+γ2)+γ1 → (e+ + e−)+γ1+γ2 (J=0,1,2), when p and p are arbitrarily polarized. We also present the partially integrated angular distribution functions in six different cases. Our results show that by measuring the two-particle angular distribution of γ 1 and γ 2 and that of γ 1 and e −, one can determine the relative magnitudes as well as the relative phases of all the helicity amplitudes in the two radiative decay processes 3D2→χ J +γ 1 and χ J →ψ+γ 2. PACS 11.80.Cr - 13.20.Fc