Abstract
A precise measurement of the atomic-mass dependence of dimuon production induced by 800-GeV protons is reported. Over 450 000 muon pairs with dimuon mass M≥4 GeV were recorded from targets of , C, Ca, Fe, and W. The ratio of dimuon yield per nucleon for nuclei versus , R=/, is sensitive to modifications of the antiquark sea in nuclei. No nuclear dependence of this ratio is observed over the range of target-quark momentum fraction 0.1<<0.3. For <0.1 the ratio is slightly less than unity for the heavy nuclei. These results are compared with predictions of models of the European Muon Collaboration effect.
- Received 1 March 1990
DOI:https://doi.org/10.1103/PhysRevLett.64.2479
©1990 American Physical Society