Chiral constraints on the isoscalar electromagnetic spectral functions of the nucleon from leading order vector meson couplings

Ünal, Y.; Meißner, Ulf‐G.

doi:10.1016/j.physletb.2019.05.029

Cited by 4 publications

(3 citation statements)

References 30 publications

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“…For recent work on the isoscalar spectral functions in baryon chiral perturbation theory with explicit vector mesons, that strengthens the findings of these earlier works, see Ref. [73]. These important ingredients are discussed in more detail below.…”

Section: Dispersion Relations and Spectral Decompositionsupporting

confidence: 63%

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

2021

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We review the dispersion-theoretical analysis of the electromagnetic form factors of the nucleon. We emphasize in particular the role of unitarity and analyticity in the construction of the isoscalar and isovector spectral functions. We present new results on the extraction of the nucleon radii, the electric and magnetic form factors and the extraction of $$\omega $$ ω -meson couplings. All this is supplemented by a detailed calculation of the theoretical uncertainties, using bootstrap and Bayesian methods to pin down the statistical errors, while systematic errors are determined from variations of the spectral functions. We also discuss the physics of the time-like form factors and point out further issues to be addressed in this framework.

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Section: Dispersion Relations and Spectral Decompositionsupporting

confidence: 63%

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

2021

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“…High-mass strength appears at t 1 GeV 2 through the K K channel and the φ resonance, as well as through other hadronic states such as πρ [46,47]. We assume that the high-mass part of the isoscalar spectral function is approximately exhausted by these states at t ∼ 1 GeV 2 and parametrize the spectral functions as where the effective pole mass is chosen as…”

Section: Appendix A: Nucleon Radiimentioning

confidence: 99%

Transverse charge and current densities in the nucleon from dispersively improved chiral effective field theory

Alarcón,

Weiss

2022

Preprint

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Background: The transverse densities ρ1,2(b) describe the distributions of electric charge and magnetic moment at fixed light-front time and connect the nucleon's elastic form factors with its partonic structure. The dispersive representation of the form factors F1,2(t) expresses the densities in terms of exchanges of hadronic states in the t-channel and permits their analysis using hadronic physics methods.Purpose: Compute the densities at peripheral distances b = O(M −1 π ), where they are generated predominantly by the two-pion states in the dispersive representation. Quantify the uncertainties.Methods: Dispersively improved chiral effective field theory (DIχEFT) is used to calculate the isovector spectral functions Im F1,2(t) on the two-pion cut. The method includes ππ interactions (ρ resonance) through elastic unitarity and provides realistic spectral functions up to t ≈ 1 GeV 2 . Higher-mass states are parametrized by effective poles and constrained by sum rules (charges, radii, superconvergence relations). The densities ρ1,2(b) are obtained from their dispersive representation. Uncertainties are quantified by varying the spectral functions. The method respects analyticity and ensures the correct b → ∞ asymptotic behavior of the densities.Results: Accurate densities are obtained at all distances b 0.5 fm, with correct behavior down to b → 0. The region of distances is quantified where transverse nucleon structure is governed by the two-pion state. The light-front current distributions in the polarized nucleon are computed and discussed.Conclusions: Peripheral nucleon structure can be computed from first principles using DIχEFT. The method can be extended to generalized parton distributions and other nucleon form factors.

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“…In this case, the low order chiral Lagrangian is enough. On the other hand, some research studies the vector mesons themselves, such as the vector meson masses [24,[57][58][59][60][61][62], their electromagnetic properties [20,63], vector meson decay constants [64], vector meson radiative decays [13], vector meson scattering with the other high energy particles [19,39,[65][66][67] and so on. Some of them study to the next-to-leading order (NLO).…”

Section: Introductionmentioning

confidence: 99%

High order chiral Lagrangians with vector mesons in different approaches

Guo¹,

Yang²,

Jiang³

2020

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The chiral Lagrangians with vector mesons are constructed in different approaches, including the next-to-leading order Lagrangian in the vector-field approach, the next-to-next-to-leading order Lagrangians in the tensor-field and the hidden local symmetry approaches. Some redundant terms are found at the next-to-leading order in the tensor-field and the hidden local symmetry approaches. The corresponding relationships between the next-to-next-to-leading order pseudoscalar mesonic low-energy constants and the ones in the hidden local symmetry approach are obtained at the tree level. The equivalence between the tensor-field approach and the hidden local symmetry approach is also discussed.

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Chiral constraints on the isoscalar electromagnetic spectral functions of the nucleon from leading order vector meson couplings

Abstract: Using baryon chiral perturbation theory including vector mesons, we analyse various continuum contributions to the isoscalar electromagnetic spectral functions of the nucleon induced by the leading order couplings.

Cited by 4 publications

References 30 publications

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

Transverse charge and current densities in the nucleon from dispersively improved chiral effective field theory

High order chiral Lagrangians with vector mesons in different approaches

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