Abstract
The nucleon’s strange electric and magnetic form factors G s E and G s M can be probed via parity-violating electron scattering. The HAPPEX Collaboration has made new measurements of the parity-violating asymmetry A PV in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with <ϑ lab > ≈ 6.0°. For 4He the preliminary result is A PV = (+6.43 ± 0.23 (stat) ± 0.22 (syst)) × 10−6. For hydrogen the preliminary result is A PV = (−1.60 ± 0.12 (stat) ± 0.05 (syst)) × 10−6. From these values we extract G s E = 0.004 ± 0.014 ± 0.013 at <Q 2> = 0.077 GeV/c 2, and G s E + 0.09G s M = 0.004 ±0.011 ± 0.005 at <Q 2> = 0.109 GeV/c 2, both consistent with zero, providing stringent new limits on the role of strange quarks in the vector structure of the nucleon.
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Armstrong, D.S. (2007). New results from the HAPPEX Experiments at Q2 = 0.1 GeV/c2 . In: de Jager, K., et al. Proceedings of The 3rd Workshop From Parity Violation to Hadronic Structure and more.... Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-74413-9_14
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DOI: https://doi.org/10.1007/978-3-540-74413-9_14
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