Asymmetries in charm production in fixed-target experiments

Summary

From the experimentalist’s viewpoint the measurement of charm production asymmetries, the ratio of charm production cross-sections for particle and anti-particle, is a very productive field. Accurate measurements can be made that are largely free of systematic errors, and since leading-order QCD calculations produce no asymmetry, these measurements test fragmentation and other effects. Simple phenomenological models explain the gross features of the data, while a variety of more detailed models attempt to fit the rich details of the present data samples. This paper will briefly highlight the differences among a few of the theoretical models, and include a brief history of recent experimental measurements. New measurements from present experiments will be presented in more detail, with an emphasis on recent results from WA89, E687 and E791. This will be followed by a short summary of results expected in the near future from these and similar experiments, and by a shorter preview of the improvements expected in the next decade.