Related Experiment Video
Updated: May 16, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Universal behavior of the [Formula: see text] transition form factors
Dmitri Melikhov1,2,3, Berthold Stech4
1HEPHY, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna, Austria.
Abstract:
The photon transition form factors of π, η and [Formula: see text] are discussed in view of recent measurements. It is shown that the exact axial anomaly sum rule allows a precise comparison of all three form factors at high-[Formula: see text] independent of the different structures and distribution amplitudes of the participating pseudoscalar mesons. We conclude: (i) The πγ form factor reported by Belle is in excellent agreement with the nonstrange [Formula: see text] component of the η and [Formula: see text] form factors obtained from the BaBar measurements. (ii) Within errors, the πγ form factor from Belle is compatible with the asymptotic pQCD behavior, similar to the η and [Formula: see text] form factors from BaBar. Still, the best fits to the data sets of πγ, ηγ, and [Formula: see text] form factors favor a universal small logarithmic rise [Formula: see text].
Related Concept Videos
Transition State Theory
Properties of Transition Metals
Convolution Properties I
The commutative property reveals that the input and the impulse response of an LTI (Linear Time-Invariant) system can be interchanged without affecting the output:
Periodic Classification of the Elements
Principle of Equivalence
System of Forces and Couples
The principle of transmissibility plays a crucial role in this process. According to...

