scholarly journals Towards a dispersive determination of the pion transition form factor

2018 ◽  
Vol 166 ◽  
pp. 00013 ◽  
Author(s):  
Stefan Leupold ◽  
Martin Hoferichter ◽  
Bastian Kubis ◽  
Franz Niecknig ◽  
Sebastian P. Schneider
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Standard Model ◽  
Model Calculation ◽  
Transition Form Factor ◽  
Current Status ◽  
Transition Form ◽  
Dispersion Theory ◽  
Ongoing Project

We start with a brief motivation why the pion transition form factor is interesting and, in particular, how it is related to the high-precision standard-model calculation of the gyromagnetic ratio of the muon. Then we report on the current status of our ongoing project to calculate the pion transition form factor using dispersion theory. Finally we present and discuss a wish list of experimental data that would help to improve the input for our calculations and/or to cross-check our results.

scholarly journals η′transition form factor from space- and timelike experimental data

2016 ◽  
Vol 94 (5) ◽  
Author(s):  
R. Escribano ◽  
S. Gonzàlez-Solís ◽  
P. Masjuan ◽  
P. Sanchez-Puertas
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form

scholarly journals PION TRANSITION FORM FACTOR AT THE TWO-LOOP LEVEL VIS-À-VIS EXPERIMENTAL DATA

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2858-2867 ◽  
Author(s):  
S. V. MIKHAILOV ◽  
N. G. STEFANIS
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Form Factor ◽  
Light Cone ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Leading Order ◽  
Transition Form ◽  
Qcd Sum Rules ◽  
Theoretical Results

We use light-cone QCD sum rules to calculate the pion-photon transition form factor, taking into account radiative corrections up to the next-to-next-to-leading order of perturbation theory. We compare the obtained predictions with all available experimental data from the CELLO, CLEO, and the BaBar Collaborations. We point out that the BaBar data are incompatible with the convolution scheme of QCD, on which our predictions are based, and can possibly be explained only with a violation of the factorization theorem. We pull together recent theoretical results and comment on their significance.

scholarly journals $$\omega \rightarrow 3\pi $$ and $$\omega \pi ^{0}$$ transition form factor revisited

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
M. Albaladejo ◽  
◽  
I. Danilkin ◽  
S. Gonzàlez-Solís ◽  
D. Winney ◽  
...  
Keyword(s):  
Form Factor ◽  
Experimental Determination ◽  
Dalitz Plot ◽  
Transition Form Factor ◽  
Decay Amplitude ◽  
Experimental Results ◽  
Transition Form ◽  
Dispersive Analysis ◽  
Low Energies

AbstractIn light of recent experimental results, we revisit the dispersive analysis of the $$\omega \rightarrow 3\pi $$ ω → 3 π decay amplitude and of the $$\omega \pi ^0$$ ω π 0 transition form factor. Within the framework of the Khuri–Treiman equations, we show that the $$\omega \rightarrow 3\pi $$ ω → 3 π Dalitz-plot parameters obtained with a once-subtracted amplitude are in agreement with the latest experimental determination by BESIII. Furthermore, we show that at low energies the $$\omega \pi ^0$$ ω π 0 transition form factor obtained from our determination of the $$\omega \rightarrow 3\pi $$ ω → 3 π amplitude is consistent with the data from MAMI and NA60 experiments.

scholarly journals Form factor π0γ*γ in lightcone sum rules combined with renormalization-group summation vs experimental data.

2019 ◽  
Vol 222 ◽  
pp. 03017 ◽  
Author(s):  
C. Ayala ◽  
S. V. Mikhailov ◽  
A. V. Pimikov ◽  
N. G. Stefanis
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Renormalization Group ◽  
Form Factor ◽  
Transition Form Factor ◽  
Sum Rules ◽  
Transition Form ◽  
Analytic Perturbation Theory ◽  
Sum Rule ◽  
Fixed Order

We consider the lightcone sum-rule (LCSR) description of the pionphoton transition form factor in combination with the renormalization group of QCD. The emerging scheme represents a certain version of Fractional Analytic Perturbation Theory and significantly extends the applicability domain of perturbation theory towards lower momenta Q2 ≲ 1 GeV2. We show that the predictions calculated herewith agree very well with the released preliminary data of the BESIII experiment, which have very small errors just in this region, while the agreement with other data at higher Q2 is compatible with the LCSR predictions obtained recently by one of us using fixed-order perturbation theory.

A COMPREHENSIVE ANALYSIS OF THE PION–PHOTON TRANSITION FORM FACTOR IN THE LEADING ORDER APPROXIMATION

2007 ◽  
Vol 22 (18) ◽  
pp. 3065-3086 ◽  
Author(s):  
TAO HUANG ◽  
XING-GANG WU
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Transition Form Factor ◽  
Order Approximation ◽  
Comprehensive Analysis ◽  
Distribution Amplitude ◽  
Leading Order ◽  
Transition Form ◽  
Photon Transition ◽  
Fock State

We perform a comprehensive analysis of the pion–photon transition form factor Fπγ(Q2) involving the transverse momentum corrections in the leading order approximation with the present CLEO experimental data, in which the contributions beyond the leading Fock state have been taken into consideration. As is well known, the leading Fock-state contribution dominates of Fπγ(Q2) at large momentum transfer (Q2) region. One should include the contributions beyond the leading Fock state in small Q2 region. In this paper, we construct a phenomenological expression to estimate the contributions beyond the leading Fock state based on its asymptotic behavior at Q2→0. Our present theoretical results agree well with the experimental data in the whole Q2 region. Then, we extract some useful information of the pionic leading twist-2 distribution amplitude (DA) by comparing our results of Fπγ(Q2) with the CLEO data. By taking best fit, we have the distribution amplitude moments, [Formula: see text] and all of higher moments, which are closed to the asymptotic-like behavior of the pion wave function.

Determination of the η-transition form factor in the γp→pη→pγe+e− reaction

2011 ◽  
Vol 701 (5) ◽  
pp. 562-567 ◽  
Author(s):  
H. Berghäuser ◽  
V. Metag ◽  
A. Starostin ◽  
P. Aguar Bartolomé ◽  
L.K. Akasoy ◽  
...  
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form

scholarly journals DISPERSION THEORY METHODS FOR TRANSITION FORM FACTORS

2014 ◽  
Vol 35 ◽  
pp. 1460461
Author(s):  
SEBASTIAN P. SCHNEIDER
Keyword(s):  
Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Dispersion Theory ◽  
Stepping Stones ◽  
Independent Determination ◽  
Model Independent ◽  
Scattering Contribution ◽  
Theoretical Analyses

Dispersion-theoretical analyses of transition form factors are stepping stones to a model-independent determination of the light-by-light scattering contribution to (g - 2)μ. We extend a calculation of the conversion decays of the lightest isoscalar vector mesons, ω/ϕ → π0ℓ+ℓ-, that builds on a previous dispersive analysis of the ω/ϕ → 3π partial-wave amplitudes and the pion vector form factor as its sole ingredients. We construct a good parametrization of e+e- → 3π that, together with information on the anomalous process γπ → ππ, allows us to obtain a description of the π0 transition form factor measured in e+e- → π0γ.

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