We present results from the initial run of Fermilab experiment E706. The data include incident π− and p beams at 500 GeV/c on Be and Cu targets, and span the kinematic ranges of transverse momentum and rapidity of 3.5≤pT≤10 GeV/c and −0.7≤yc.m.≤0.7, respectively. We have measured cross sections for π0 and direct-photon production, as well as the ηπ0 production ratio. From the data on Be and Cu, we have extracted the nuclear dependence of π0 production, parametrized as Aα. The cross sections are compared with next-to-leading-log QCD predictions for different choices of the QCD momentum scales and several sets of parton distribution functions.
No description provided.
No description provided.
No description provided.
Data on the multiplicity and inclusive spectra of γ produced in inelastic pNe20 and pN interactions at 300 GeV are presented. The γ multiplicity for pNe20 interactions is 11.43±0.23, and the ratio of 〈nγ〉 for pNe20 and pN interactions is 1.48±0.05. From an analysis of the effective-mass distributions, 〈nπ0〉=4.91±0.52 and 〈nη0〉=1.47±0.33. In fact, η0 production is much higher in pNe20 interactions [R(η0π0)=0.66±0.12 for np≥21] than in pN interactions [R(η0π0)=0.06±0.04]. No η′(958) signal is seen. Strong correlations between 〈nγ〉 and np, the number of secondary protons, are observed, primarily from the central and target fragmentation regions. Inclusive y* and p⊥ spectra are analyzed and evidence for low-energy cascading and rescattering of fast particles in the projectile fragmentation region is discussed. The data are compared to the predictions of the additive quark model, the Lund model, and the dual parton model.
No description provided.
GAMMA-MULTIPLICITY FOR (PROTON-NUCLEON)-INTERACTION WAS OBTAINED AT AVERAGING OVER (PP) AND (PN) EVENTS, AND THEN WAS USED IN THE PRESENTED RATIO.
No description provided.
Forum