Constraints on $s-\bar s$ asymmetry of the proton in chiral effective theory

分类： 物理学 >> 核物理学 提交时间： 2016-08-31

X. G. Wang Chueng-Ryong Ji W. Melnitchouk Y. Salamu A. W. Thomas P. Wang

摘要： We compute the s−s¯ asymmetry in the proton in chiral effective theory, using phenomenological constraints based upon existing data. Unlike previous meson cloud model calculations, which accounted for kaon loop contributions with on-shell intermediate states alone, this work includes off-shell terms and contact interactions, which impact the shape of the s−s¯ difference. Using a regularization procedure that preserves chiral symmetry and Lorentz invariance, we find that existing data limit the integrated value of the first moment of the asymmetry to the range −0.07×10−3≤⟨x(s−s¯)⟩≤1.12×10−3 at a scale of Q2=1GeV2. In contrast to some suggestions in the literature, the magnitude of this correction is too small to account for the NuTeV anomaly.

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