Constraints on the nucleon strange form factors at Q2∼0.1 GeV2

• DOI: 10.1016/j.physletb.2006.03.011
• Publication Date: 2006-03-21T12:15:54Z
• Authors: K.A. Aniol; D.S. Armstrong; T. Averett; H. Benaoum; P.Y. Bertin; E. Burtin; J. Cahoon; G.D. Cates; C.C. Chang; Y.-C. Chao; J.P. Chen; Seonho Choi; E. Chudakov; B. Craver; F. Cusanno; P. Decowski; D. Deepa; C. Ferdi; R.J. Feuerbach; J.M. Finn; S. Frullani; K. Fuoti; F. Garibaldi; R. Gilman; A. Glamazdin; V. Gorbenko; J.M. Grames; J. Hansknecht; D.W. Higinbotham; R. Holmes; T. Holmstrom; T.B. Humensky; H. Ibrahim; C.W. de Jager; X. Jiang; L.J. Kaufman; A. Kelleher; A. Kolarkar; S. Kowalski; K.S. Kumar; D. Lambert; P. LaViolette; J. LeRose; D. Lhuillier; N. Liyanage; D.J. Margaziotis; M. Mazouz; K. McCormick; D.G. Meekins; Z.-E. Meziani; R. Michaels; B. Moffit; P. Monaghan; C. Munoz-Camacho; S. Nanda; V. Nelyubin; D. Neyret; K.D. Paschke; M. Poelker; R. Pomatsalyuk; Y. Qiang; B. Reitz; J. Roche; A. Saha; J. Singh; R. Snyder; P.A. Souder; M. Stutzman; R. Subedi; R. Suleiman; V. Sulkosky; W.A. Tobias; G.M. Urciuoli; A. Vacheret; E. Voutier; K. Wang; R. Wilson; B. Wojtsekhowski; X. Zheng
• Keywords: Parity (physics)

We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The was carried out with beam energy 3.03 GeV and scattering angle =6 degrees, result A_PV = -1.14 +/- 0.24 (stat) 0.06 (syst) parts per million. From this we extract, at Q^2 0.099 GeV^2, strange form factor combination G_E^s + 0.080 G_M^s 0.030 0.025 0.006 0.012 (FF) where first two errors are experimental last error is due uncertainty neutron electromagnetic factor. This significantly improves current knowledge ~0.1 GeV^2. A consistent picture emerges when several measurements about same value combined: zero while prefers positive values though G_E^s=G_M^s=0 compatible data 95% C.L.