1932

Abstract

We review the production of high-mass lepton pairs in fixed-target experiments, including both Drell-Yan (DY) and heavy quarkonium production [/ψ, ψ′, ϒ(1), ϒ(2), and ϒ(3)]. In recent years, DY data have become standard input to the determination of parton density distributions. DY data have recently yielded the first measurement of the dependence of the , asymmetry of the proton. Similar to the observations in deeply inelastic scattering, precision measurements of the nuclear dependence of the proton-induced DY process exhibit shadowing at small target momentum fraction, . There is, however, no evidence of enhanced DY production from nuclear targets. Mean transverse momenta of DY pairs are observed to increase with target mass. These data, analyzed within a new theoretical framework, provide an estimation of the energy loss of fast quarks in nuclear matter. In contrast to the DY process, there are large nuclear effects in the production of all quarkonia. These effects show strong dependence on and but do not scale with . Statistically less precise measurements of meson (open-charm) production at small are consistent with no nuclear dependence.

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/content/journals/10.1146/annurev.nucl.49.1.217
1999-12-01
2024-06-18
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  • Article Type: Review Article
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