Search

Total and differential cross sections for production of the ρ, ω, φ, and J/ψ vector mesons were measured in the Feynman‐x region 0.1≤xF≤0.8 with a 530 GeV/cπ− beam incident on beryllium and copper targets. Using the cross‐section parametrization Aα, we find α=0.76±0.02, 0.81±0.04, 0.87±0.04, and 0.97±0.06 for the ρ/ω, φ, Jψ and Drell‐Yan continuum, respectively. No statistically significant dependence of α on either xF or transverse momentum pT is observed. We have also studied the relative production rates of vector mesons as a function of the event inelasticity, as measured by transverse energy, ET. ET is defined as the scalar sum of transverse momenta for centrally produced charged particles. The relative rate of J/ψ’s and continuum muon pairs does not change with event inelasticity, contrary to the findings of a heavy‐ion collision experiment. On the other hand, the production rate of φ mesons as compared to ρ/ω increases with ET. We argue that the observed increase reflects a simple momentum conserva...

We are studying production of χc states in 530 GeV/c π− interactions with several targets. χc mesons are observed in the mode (χ→J/ψ+γ). Only photons that converted to e+e− pairs are used in the reconstruction of the χc mesons. Preliminary analysis shows that the fraction of observed J/ψs coming from χc radiative decays is 0.44±0.09±0.08, and that the relative production rate of χc1 to χc2 is 1.3±0.6.