The decay rate for ${\eta }_c$→pp¯ is computed at the tree level in perturbative QCD, modeling the proton with a quark-diquark system. Satisfactory agreement with the data is obtained. Comparisons with pure-quark models are made and predictions are given for this and other heavy-pseudoscalar-meson decay rates into baryon-antibaryon.

• Received 17 February 1988

DOI:https://doi.org/10.1103/PhysRevD.38.3516