Lepton-pair angular distributions from hadronic production ofJψ

Abstract

We derive analytic and numerical expressions for the complete angular distributions and cross sections of lepton pairs coming from the decay of hadronically produced $\frac{J}{\psi }$ for each of six dynamical processes: five processes mediated by various $\chi$ intermediate states, formed by gluons and quarks, and the direct fusion of quarks into $\frac{J}{\psi }$. The proportion of the contributions of these six processes to $\pi N$, $\mathrm{pN}$, $\overline{p}N$ collisions depends on parameters that have not been well determined. We have, nevertheless, made an attempt to fix these parameters in order to make predictions for the angular distributions and cross sections of these hadronic processes. The results agree reasonably well with the angular distributions of the few available experiments as well as the percentage of $\chi$ contributions to total cross sections.