Hadroproduction of the Jψ and ψ′ states has been studied in 300-GeV/c proton, antiproton, and π±Li interactions. Both total and differential cross sections in xF and pT have been measured for the Jψ for the π±, proton, and antiproton interactions. The ratio of ψ′ to Jψ production has been determined for the four types of beam particles.
Absolute cross sections as functions of kinematic variables are presented for the production of muon pairs from 800 GeV proton bombardment of H2. Drell-Yan (continuum) dimuons were recorded in the mass regions 4.5≤Mμ+μ−≤9 GeV and Mμ+μ−≥11 GeV, with an x-Feynman range -0.1≤xF≤0.75. This range corresponds to smaller masses and larger values of xF than previous 800 GeV Drell-Yan data. Cross sections for the Υ(1S) resonance are also given versus the transverse momentum and xF.
We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, $\sigma (p + d \to \Upsilon) / 2\sigma (p + p\to \Upsilon)$, is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0 < x_F < 0.6, this ratio is found to be consistent with unity, in striking contrast to the behavior of the Drell-Yan cross section ratio $\sigma(p+d)_{DY}/2\sigma(p+p)_{DY}$. This result shows that the gluon distributions in the proton and neutron are very similar. The Upsilon production cross sections are also compared with the p+d and p+Cu cross sections from earlier measurements.
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