https://doi.org/10.1140/epjc/s10052-008-0649-8
Regular Article - Theoretical Physics
Polarized angular distributions in the decays of the ψ’ charmonium state directly produced in unpolarized proton–antiproton collisions
1
Department of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
2
Department of Physics, University of Massachusetts at Lowell, Lowell, Massachusetts, 01854, USA
* e-mail: wkmok@hkbu.edu.hk
Received:
10
April
2008
Revised:
9
May
2008
Published online:
2
July
2008
Using the helicity formulism, we calculate the combined angular distribution function of the polarized gamma photons and electron in the cascade process pp̄→ψ’→χJ+γ1→ψ+γ2+γ1→e++e-+γ2+γ1 (J=0,1,2), when p̄ 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.
© Springer-Verlag , 2008