Signals for the formation of the singlet D and P states of charmonium in p̄p collisions

We calculate the angular distribution of the photons produced in the decays of the singlet D and singlet P states in charmonium directly produced by unpolarized proton-antiproton (pp̄) collisions. The reactions we study are (1) pp̄→1D2→1P1+γ, (2) pp̄→1D2→1 3S1+γ, and (3) pp̄→1P1→1S0+γ. We also study the angular distribution of the electron (e-) in the cascade process (4) pp̄→1P1→ψ+π0→(e+e-)+(γ1γ2). Simple and distinct expressions are found for each case. The observation of the photon or electron (as the case may be) with the appropriate energy and the distinct angular distribution may be taken as a signal for the formation of the singlet D and P state resonance formation in pp̄ collisions.