Asymptotic behavior of meson transition form factors

Hoferichter, Martin; Stoffer, Peter

doi:10.1007/jhep05(2020)159

Cited by 68 publications

(59 citation statements)

References 107 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A good agreement with F ∞ presumes saturation of the scaled TFF at large Q 2 and entails the onset of scaling. The big unknown is at which momentum scale this becomes obvious [81,82]. The overall agreement of the TFF predictions, obtained in this work with the set of the BMS DAs [16] (including the platykurtic one [17]), with the CLEO [11], BABAR(<9 GeV 2 ) [3], and Belle [4] data is good and any discrepancies are within the corresponding experimental errors, see Fig.…”

Section: Discussionsupporting

confidence: 74%

Pion-photon transition form factor in light cone sum rules and tests of asymptotics

Stefanis

2020

Phys. Rev. D

View full text Add to dashboard Cite

We study the pion-photon transition form factor (TFF) F γÃγπ 0 ðQ 2 Þ using a state-of-the art implementation of light cone sum rules (LCSRs) within fixed-order QCD perturbation theory. The spectral density in the dispersion relation includes all currently known radiative corrections up to the next-to-next-to-leadingorder (NNLO) and all twist contributions up to order six. Predictions for the TFF are obtained for various pion distribution amplitudes (DAs) of twist two, including two-loop evolution which accounts for heavyquark mass thresholds. The influence of the main theoretical uncertainties is quantified in order to enable a more realistic comparison with the data. The characteristics of various pion DAs are analyzed in terms of the conformal coefficients a 2 and a 4 in comparison with the 1σ and 2σ error regions of the data and the most recent lattice constraints on a 2 with NLO and NNLO accuracy. Our results provide more stringent bounds on the variation of the pion DA and illuminate the corresponding asymptotic behavior of the calculated TFF.

show abstract

Section: Discussionsupporting

confidence: 74%

Pion-photon transition form factor in light cone sum rules and tests of asymptotics

Stefanis

2020

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…Furthermore, it yields asymptotic axial TFFs whose momentum dependence is consistent with the behavior derived in Ref. [29]. The infinite tower of axials has the correct momentum scaling in the asymmetric asymptotic regime dictated by the OPE constraint, but the coefficient is 38% too small [40].…”

Section: Including Ground-state Axial Mesons At Low Energiessupporting

confidence: 82%

“…Tree-level resonance exchanges cannot make a HLbL μ comply with all SDCs unless an infinite number of states is included. This is due to the fact that the transition form factors (TFFs) describing the resonance couplings to offshell photons are subject themselves to asymptotic QCD constraints [27][28][29], which make the full HLbL four-point function decay too fast at high virtualities. 1 MV proposed a model to satisfy the longitudinal and transversal OPE SDCs through a modification of the pion pole contribution [25,31], which affects also the low-energy region.…”

Section: (): V-volmentioning

confidence: 99%

Effects of longitudinal short-distance constraints on the hadronic light-by-light contribution to the muon $$\mathbf {g-2}$$

Lüdtke

Procura

2020

Eur. Phys. J. C

View full text Add to dashboard Cite

We present a model-independent method to estimate the effects of short-distance constraints (SDCs) on the hadronic light-by-light contribution to the muon anomalous magnetic moment $$a_\mu ^\text {HLbL}$$ a μ HLbL . The relevant loop integral is evaluated using multi-parameter families of interpolation functions, which satisfy by construction all constraints derived from general principles and smoothly connect the low-energy region with those where either two or all three independent photon virtualities become large. In agreement with other recent model-based analyses, we find that the SDCs and thus the infinite towers of heavy intermediate states that are responsible for saturating them have a rather small effect on $$a_\mu ^\text {HLbL}$$ a μ HLbL . Taking as input the known ground-state pseudoscalar pole contributions, we obtain that the longitudinal SDCs increase $$a_\mu ^\text {HLbL}$$ a μ HLbL by $$(9.1\pm 5.0) \times 10^{-11}$$ ( 9.1 ± 5.0 ) × 10 - 11 , where the isovector channel is responsible for $$(2.6\pm 1.5) \times 10^{-11}$$ ( 2.6 ± 1.5 ) × 10 - 11 . More precise estimates can be obtained with our method as soon as further accurate, model-independent information about important low-energy contributions from hadronic states with masses up to 1–2 GeV become available.

show abstract

“…In contrast to the usual simple model for the axial vector TFF involving a factorized dipole ansatz [12], the holographic result (1) is asymmetric in the photon virtualities 2 1 , 2 2 . Its high-energy limit coincides with the asymmetric asymptotic form following from perturbative QCD, which has only most recently been derived in [13].…”

Section: Axial Vector Tffs Andmentioning

confidence: 52%

Axial vector transition form factors in holographic QCD and their contribution to the anomalous magnetic moment of the muon

Leutgeb

Rebhan

2020

Phys. Rev. D

View full text Add to dashboard Cite

Whereas the theoretical results for the dominant contributions to hadronic light-by-light scattering coming from pseudoscalar meson exchange have converged over the past years, the various published estimates of the contribution due to axial vector meson exchange differ wildly. Since holographic AdS/QCD models have proved to provide rather good models of singly and doubly virtual pion transition form factors, which reproduce remarkably well the known low-energy data and also the asymptotic leading-order pQCD behavior, it is of interest to consider their predictions for axial vector transition form factors. Indeed, we find that these reproduce also very well existing data from the L3 experiment for 1 → *. Including the full infinite tower of axial vector mesons of the AdS/QCD models we moreover show that the Melnikov-Vainshtein shortdistance constraint can be satisfied, while almost all existing models for hadronic light-by-light scattering fail to incorporate it. The contribution to − 2, which is dominated by the first few resonances, turns out to be significantly larger than estimated previously.

show abstract

Asymptotic behavior of meson transition form factors

Cited by 68 publications

References 107 publications

Pion-photon transition form factor in light cone sum rules and tests of asymptotics

Pion-photon transition form factor in light cone sum rules and tests of asymptotics

Effects of longitudinal short-distance constraints on the hadronic light-by-light contribution to the muon $$\mathbf {g-2}$$

Axial vector transition form factors in holographic QCD and their contribution to the anomalous magnetic moment of the muon

Contact Info

Product

Resources

About