Strange quark asymmetry in the proton in chiral effective theory

Abstract

We perform a comprehensive analysis of the strange-antistrange parton distribution function (PDF) asymmetry in the proton in the framework of chiral effective theory, including the full set of lowest order kaon loop diagrams with off-shell and contact interactions, in addition to the usual on-shell contributions previously discussed in the literature. We identify the presence of $\delta$-function contributions to the $\bar{s}$ PDF at $x=0$, with a corresponding valence-like component of the $s$-quark PDF at larger $x$, which allows greater flexibility for the shape of $s-\bar{s}$. Expanding the moments of the PDFs in terms of the pseudoscalar kaon mass, we compute the leading nonanalytic behavior of the number and momentum integrals of the $s$ and $\bar{s}$ distributions, consistent with the chiral symmetry of QCD. We discuss the implications of our results for the understanding of the NuTeV anomaly and for the phenomenology of strange quark PDFs in global QCD analysis.

47 pages, 7 figures, 2 tables

References in corpus (11)

• Parton distributions in the LHC era: MMHT 2014 PDFs
• Extraction of Spin-Dependent Parton Densities and Their Uncertainties
• Chiral Perturbation Theory and Baryon Properties
• Soft-Gluon Resummation and the Valence Parton Distribution Function of the Pion
• The SAMPLE Experiment and Weak Nucleon Structure
• Testing the Standard Model by precision measurement of the weak charges of quarks
• Isovector EMC effect explains the NuTeV anomaly
• Parity-Violating Electron Scattering and the Electric and Magnetic Strange Form Factors of the Nucleon
• Determination of Strange Sea Quark Distributions from Fixed-target and Collider Data
• Pion momentum distributions in the nucleon in chiral effective theory
• Constraining nucleon strangeness

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• The Sea of Quarks and Antiquarks in the Nucleon: a Review
• What does kinematical target mass sensitivity in DIS reveal about hadron structure?
• The Spin Budget of the Proton at NNLO and Beyond
• Helicity-dependent distribution of strange quarks in the proton from nonlocal chiral effective theory