Study of the angular distribution of the reaction pp→χc2→J/ψ→e+e−γ

We report on a study of the angular distribution in the reaction pp → χ c 2 → J/ψγ → e + e − γ. Using a sample of 1904 events, we find that the contribution of helicity zero in the formation process is B 0 2 < 0.22 (90% C.L.), and that the normalized quadrupole amplitude in the radiative decay is a 2 = −0.14 ± 0.06. The normalized radiative decay octupole amplitude a 3 is found to be consistent with zero