Constraints on the asymmetry of the proton in chiral effective theory

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• 作者：X.G. Wang^a ; Chueng-Ryong Ji^b ; W. Melnitchouk^c ; ^{wmelnitc@jlab.org" class="auth_mail" title="E-mail the corresponding author} ; Y. Salamu^d ; A.W. Thomas^a ; P. Wang^d ; ^e
• 关键词：Strange asymmetry ; Chiral symmetry ; Kaon loops
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 November 2016
• 年：2016
• 卷：762
• 期：Complete
• 页码：52-56
• 全文大小：373 K

文摘

We compute the yJSB inlineImage" height="11" width="30" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305081-si1.gif"> 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 yJSB inlineImage" height="11" width="30" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305081-si1.gif"> difference. We identify a valence-like component of s(x) which is balanced by a δ  -function contribution to yJSB inlineImage" height="14" width="24" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305081-si3.gif"> at abea74dbf488dd" title="Click to view the MathML source">x=0$x=0$, so that the integrals of s   and yJSB inlineImage" height="11" width="8" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305081-si5.gif"> over the experimentally accessible region x>0$x>0$ are not equal. Using a regularization procedure that preserves chiral symmetry and Lorentz invariance, we find that existing data limit the integrated value of the second moment of the asymmetry to the range yJSB inlineImage" height="16" width="246" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305081-si7.gif"> at a scale of Q²=1 GeV²$Q^2=1{\text{GeV}}^2$. This is too small to account for the NuTeV anomaly and of the wrong sign to enhance it.