Angular distributions in the decays of the ψ’ charmonium state directly produced in polarized proton-antiproton collisions

Abstract

Using the helicity formulism, we calculate the combined angular distribution function of the polarized gamma photons and electron in the cascade process pp→ψ’→χJ+γ1→ψ+γ2+γ1→e++e-+γ2+γ1 (J=0,1,2), when p and p are unpolarized. We also present the partially integrated angular distribution functions in different cases. Our results show that by measuring the two-particle angular distribution of γ1 and γ2 and that of γ2 and e- with the polarization of either one of the two particles, one can determine the relative magnitudes as well as the relative phases of the helicity amplitudes in the radiative decay processes ψ’→χJ+γ1 and χJ→ψ+γ2.