QCD Mechanisms for Double Quarkonium and Open Heavy Meson Hadroproduction

Abstract

Double $J/ψ$ production on the order of 20-30 pb has been observed by the NA3 collaboration. These $ψψ$ pairs, measured in $π^- N$ interactions at 150 and 280 GeV$/c$ and in $pN$ interactions at 400 GeV$/c$, carry a large fraction of the projectile momentum, $x_{ψψ} \geq 0.6$ for the 150 GeV$/c$ beam and $\geq 0.4$ at 280 GeV$/c$. We examine several sources of $ψψ$ pair production within QCD, including ${\cal O}(α_s^4)$ $ψψ$ production, leading-twist $b \overline b$ production and decay, and the materialization of heavy-quark Fock states in the projectile. We estimate the production cross section and the single and double $J/ψ$ momentum and mass distributions for each, comparing the results with the NA3 data, and predict $ψψ$ production in $pN$ interactions at 800 GeV$/c$, accessible to current fixed-target experiments. We also discuss the observable implications of open heavy meson pair production from the intrinsic heavy quark Fock states.

Revtex, APS style, 16 pages, 15 figures available as uuencoded postscript files (or ps files) from the Author