Perturbative Generation of a Strange-Quark Asymmetry in the Nucleon

Catani, Stefano; Florian, Daniel de; Rodrigo, Germán; Vogelsang, Werner

doi:10.1103/physrevlett.93.152003

Cited by 101 publications

(116 citation statements)

References 30 publications

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“…This latter quantity has been determined by various groups, at various scales: several of these results are collected in Table 10 and compared to our own. Results are given both at the scale at which they were determined, and then also when evolved to a common scale, exploiting the fact that at NLO (though not at NNLO [43]) [S − ] evolves multiplicatively. In this case, too, the NNPDF1.2 uncertainty is much larger than that obtained in other fits: while for all other groups there is an indication that a positive value of [S − ] is favored (all results being nevertheless compatible with zero), this indication looses its significance in our analysis due to the very large uncertainty.…”

Section: Discussionmentioning

confidence: 99%

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Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

et al. 2009

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Abstract:We use recent neutrino dimuon production data combined with a global deep-inelastic parton fit to construct a new parton set, NNPDF1.2, which includes a determination of the strange and antistrange distributions of the nucleon. The result is characterized by a faithful estimation of uncertainties thanks to the use of the NNPDF methodology, and is free of model or theoretical assumptions other than the use of NLO perturbative QCD and exact sum rules. Better control of the uncertainties of the strange and antistrange parton distributions allows us to reassess the determination of electroweak parameters from the NuTeV dimuon data. We perform a direct determination of the |V cd | and |V cs | CKM matrix elements, obtaining central values in agreement with the current global CKM fit: specifically we find |V cd | = 0.244 ± 0.019 and |V cs | = 0.96 ± 0.07. Our result for |V cs | is more precise than any previous direct determination. We also reassess the uncertainty on the NuTeV determination of sin 2 θ W through the Paschos-Wolfenstein relation: we find that the very large uncertainties in the strange valence momentum fraction are sufficient to bring the NuTeV result into complete agreement with the results from precision electroweak data.1

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Section: Discussionmentioning

confidence: 99%

“…Using the value of R S Eq. (20), obtained at the typical scale Q 2 = 20 GeV 2 of the NuTeV data (and whose scale dependence is very small anyway [43]) we obtain δ s sin 2 θ W = −0.001 ± 0.011 PDFs ± 0.002 th ,…”

Section: Pdf Corrections To the Paschos-wolfenstein Ratiomentioning

confidence: 99%

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

et al. 2009

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“…Consequently previous NLO estimates of the effect of, for instance, the (presumably mainly non-perturbative, see Refs. [47][48][49]) charge asymmetry of the strange sea remain practically unaffected by higher-order corrections to the coefficient functions.…”

Section: Applicationsmentioning

confidence: 99%

Differences between charged-current coefficient functions

2008

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Second-and third-order results are presented for the structure functions of charged-current deepinelastic scattering in the framework of massless perturbative QCD. We write down the two-loop differences between the corresponding crossing-even and -odd coefficient functions, including those for the longitudinal structure function not covered in the literature so far. At three loops we compute the lowest five moments of these differences for all three structure functions and provide approximate expressions in Bjorken-x space. Also calculated is the related third-order coefficient-function correction to the Gottfried sum rule. We confirm the conjectured suppression of these quantities if the number of colours is large. Finally we derive the second-and third-order QCD contributions to the Paschos-Wolfenstein ratio used for the determination of the weak mixing angle from neutrino-nucleon deep-inelastic scattering. These contributions are found to be small.

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“…Catani et al [16], for instance, showed that perturbative three-loop effects can induce nonzero negative S − values, S − ≈ −0.5 × 10 −3 , through Q 2 evolution of symmetric s/s distributions from a low input scale, Q 0 ≈ 0.5 GeV. Nonperturbatively, the most common approach to computing the s −s asymmetry has been in the framework of meson cloud models, which focus on the role of the nucleon's light-front wave function with Fock state component consisting of kaons and hyperons, Y = Λ, Σ, .…”

Section: Introductionmentioning

confidence: 99%

“…While the generation of ss pairs through perturbative gluon radiation typically produces symmetric s ands distributions (at least up to two loop corrections [16]), any significant difference between the momentum dependence of the s ands parton distribution functions (PDFs) would be a clear signal of nonperturbative effects. In fact, insights from chiral symmetry breaking in the nonstrange sector led to the prediction [17] of an excess ofd antiquarks over u in the proton, which was spectacularly confirmed in DIS [18,19] and Drell-Yan [20,21] experiments more than a decade later.…”

Section: Introductionmentioning

confidence: 99%

Strange-quark asymmetry in the proton in chiral effective theory

Wang

Melnitchouk

et al. 2016

Phys. Rev. D

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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 δ-function contributions to thes 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 −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 ands 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.

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Perturbative Generation of a Strange-Quark Asymmetry in the Nucleon

Cited by 101 publications

References 30 publications

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

Differences between charged-current coefficient functions

Strange-quark asymmetry in the proton in chiral effective theory

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