Two-photon form factors of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>η</mml:mi></mml:math>, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>η</mml:mi><mml:mo>′</mml:mo></mml:msup></mml:math>mesons in the chiral theory with resonances

Czyż, Henryk; Ivashyn, S.; Korchin, A. Yu.; Shekhovtsova, O.

doi:10.1103/physrevd.85.094010

Cited by 52 publications

(76 citation statements)

References 94 publications

(132 reference statements)

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“…Our choice is based on the precision achieved by the PAs. While for the η TFF the P N N (Q 2 ) sequence reaches only the N = 1 element, with the consequent lack of stability checks and big uncertainties discussed above, the η TFF reaches N = 2 6 The axial-vector currents are defined as A a µ =qγµγ 5 λa √ 2 q, with…”

Section: η-η Mixing From the Tffsmentioning

confidence: 99%

“…An older phenomenological analysis based on the FKS scheme leads to F q /F π = 1.07(3), F s /F π = 1.34 (6) and φ = 39.3(1.0)…”

Section: η-η Mixing From the Tffsmentioning

confidence: 99%

“…Concerning the slope parameter, chiral perturbation theory (ChPT) predicts [2,3] b η = 0.51 and b η = 1.47 for sin θ P = −1/3 [4], being θ P the η-η mixing angle in the octet-singlet basis defined at lowest order. Other theoretical predictions are [4]: b η = 0.53 and b η = 1.33, from vector meson dominance (VMD); b η = 0.51 and b η = 1.30, from constituent-quark loops; b η = 0.36 and b η = 2.11, from the Brodsky-Lepage interpolation formula [5]; and b η = 0.521 (2) and b η = 1.323 (4), from resonance chiral theory [6]. More recently, the values b η = 0.61 −0.12 have been obtained from a dispersive analysis for η → γγ [7].…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, such a description is still lacking for the η and η [6,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] (see also a first attempt beyond single-pole interpolation formulas in Ref. [24]).…”

Section: Introductionmentioning

confidence: 99%

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$\eta$ and $\eta '$ transition form factors from rational approximants

Escribano¹

2014

Proceedings of XV International Conference on Hadron Spectroscopy — PoS(Hadron 2013)

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The η and η transition form factors in the space-like region are analyzed at low and intermediate energies in a model-independent way through the use of rational approximants. The slope and curvature parameters of the form factors as well as their values at zero and infinity are extracted from experimental data. The impact of these results on the mixing parameters of the η-η system and the pseudoscalar-exchange contributions to the hadronic light-by-light scattering part of the anomalous magnetic moment aµ are also discussed.

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Section: η-η Mixing From the Tffsmentioning

confidence: 99%

“…An older phenomenological analysis based on the FKS scheme leads to F q /F π = 1.07(3), F s /F π = 1.34 (6) and φ = 39.3(1.0)…”

Section: η-η Mixing From the Tffsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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$\eta$ and $\eta '$ transition form factors from rational approximants

Escribano¹

2014

Proceedings of XV International Conference on Hadron Spectroscopy — PoS(Hadron 2013)

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“…The feasibility of the TFF measurements at BESIII has been studied [25] using the Ekhara [26,27] event generator. It was found that using data taken at the ψ(3770) peak the TFF's of π 0 , η and η mesons can be extracted at momentum transfers in the range of 0.3 ≤ Q 2 [GeV 2 ] ≤ 10.…”

Section: Br Mesons Producedmentioning

confidence: 99%

Studies of Light Pseudoscalar Mesons at BESIII

Redmer

2014

EPJ Web of Conferences

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Pseudoscalar pole light-by-light contributions to the muon (g − 2) in resonance chiral theory

Guevara

Roig²,

Sanz-Cillero

2018

J. High Energ. Phys.

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We have studied the P → γ ⋆ γ ⋆ transition form-factors (P = π 0 , η, η ′ ) within a chiral invariant framework that allows us to relate the three form-factors and evaluate the corresponding contributions to the muon anomalous magnetic moment aµ = (gµ − 2)/2, through pseudoscalar pole contributions. We use a chiral invariant Lagrangian to describe the interactions between the pseudo-Goldstones from the spontaneous chiral symmetry breaking and the massive meson resonances. We will consider just the lightest vector and pseudoscalar resonance multiplets. Photon interactions and U (3) flavor breaking effects are accounted for in this covariant framework. This article studies the most general corrections of order m 2 P within this setting. Requiring short-distance constraints fixes most of the parameters entering the form-factors, consistent with previous determinations. The remaining ones are obtained from a fit of these form-factors to experimental measurements in the space-like (q 2 ≤ 0) region of photon momenta. No time-like observable is included in our fits. The combination of data, chiral symmetry relations between form-factors and high-energy constraints allows us to determine with improved precision the on-shell Ppole contribution to the Hadronic Light-by-Light scattering of the muon anomalous magnetic moment: we obtain a P,HLbL µ = (8.47 ± 0.16) · 10 −10 for our best fit. This result was obtained excluding BaBar π 0 data, which our analysis finds in conflict with the remaining experimental inputs. This study also allows us to determine the parameters describing the η − η ′ system in the two-mixing angle scheme and their correlations. Finally, a preliminary rough estimate of the impact of loop corrections (1/NC ) and higher vector multiplets (asym) enlarges the uncertainty up to a P,HLbL µ = ( 8.47 ± 0.16sta ± 0.09 1/N C +0.5 −0 asym ) · 10 −10 . Conclusions 36A Wess-Zumino-Witten Lagrangian 38 B The P form-factor in the evaluation of a HLbL µ 38 C Additional information on the fit correlations 401 The same deviation is quoted in the updated analysis of the leading hadronic vacuum polarization contribution in ref.[17], while it is 3.7σ according to the most recent study in [18]. See ref.[19] for a discussion on the Monte Carlo needs for these accurate predictions.2 Also lattice QCD simulations have recently managed to give accurate determinations. See, e.g., refs. [25].3 This dominance is not fully understood from a first-principles derivation [32,33].

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Two-photon form factors of theπ0,η, andη′mesons in the chiral theory with resonances

Cited by 52 publications

References 94 publications

$\eta$ and $\eta '$ transition form factors from rational approximants

$\eta$ and $\eta '$ transition form factors from rational approximants

Studies of Light Pseudoscalar Mesons at BESIII

Pseudoscalar pole light-by-light contributions to the muon (g − 2) in resonance chiral theory

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