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Improved measurement of the d ¯ / ū asymmetry in the nucleon sea

2001; American Physical Society; Volume: 64; Issue: 5 Linguagem: Inglês

10.1103/physrevd.64.052002

1538-4500

R. S. Towell, P. L. McGaughey, T. C. Awes, M. Beddo, M. L. Brooks, C. N. Brown, J. D. Bush, T. A. Carey, T. H. Chang, W. E. Cooper, C. A. Gagliardi, G. T. Garvey, D. F. Geesaman, E. Hawker, X. He, L. Isenhower, Daniel M. Kaplan, S. Kaufman, P. Kirk, D. D. Koetke, G. S. Kyle, D. M. Lee, W. M. Lee, M. J. Leitch, N. C. R. Makins, J. M. Moss, B. Mueller, P. M. Nord, V. Papavassiliou, B. K. Park, J. C. Peng, G. Petitt, P. E. Reimer, M. E. Sadler, W. E. Sondheim, P. W. Stankus, T. N. Thompson, R. E. Tribble, M. A. Vasiliev, yibo wang, Z. F. Wang, J. C. Webb, J. L. Willis, Derek K. Wise, G. R. Young,

Quantum Chromodynamics and Particle Interactions

Measurements of the ratio of Drell-Yan yields from an 800 \rm{GeV/c} proton beam incident on liquid hydrogen and deuterium targets are reported. Approximately 360,000 Drell-Yan muon pairs remained after all cuts on the data. From these data, the ratio of anti-down ($\bar{d}$) to anti-up ($\bar{u}$) quark distributions in the proton sea is determined over a wide range in Bjorken-$x$. These results confirm previous measurements by E866 and extend them to lower $x$. From these data, $(\bar{d}-\bar{u})$ and $\int(\bar{d}-\bar{u})dx$ are evaluated for $0.015<x<0.35$. These results are compared with parameterizations of various parton distribution functions, models and experimental results from NA51, NMC, and HERMES.