ψ production in p¯ N and π-N interactions at 125 GeV/c and a determination of the gluon structure functions of the p¯ and the π^-

Abstract

We have measured the cross section for production of ψ and ψ' in ρ¯ and π- interactions with Be, Cu, and W targets in experiment E537 at Fermilab. The measurements were performed at 125 GeV/c using a forward dimuon spectrometer in a closed geometry configuration. The gluon structure functions of the ρ¯ and π- have been extracted from the measured ds/dx_F spectra of the produced ψ 's. From the ρ¯ W data we obtain, for ρ¯ , xG(x)=(2.15± 0.7)[1-x]^{(6.83± 0.5)}[1+(5.85± 0.95)x]. In the ρ- case, we obtain, from the W and the Be data separately, xG(x)=(1.49± 0.03)[1-x]^{(1.98± 0.06)} (for π-W), xG(x)=(1.10± 0.10)[1-x]^{(1.20 ± 0.20)} (for π-Be).