The photon-pion transition form factor: incompatible data or incompatible models?

Abstract

The elastic and $\gamma \to \pi$ transition form factors of the pion along with its usual static observables are calculated within a light-front field approach to the constituent quark model. The focus of this exercise in a simple model is on a unified description of all observables with one singly parametrized light-front wave function to detect possible discrepancies in experimental data, in particular the contentious large momentum-squared data on the transition factor as reported by BaBar and Belle. We also discuss the relation of a small to vanishing pion charge radius with an almost constant pion distribution amplitude and compare our results with those obtained in a holographic light-front model.

Invited contribution to the Light Cone 2013 Conference in Skiathos, Greece, 20-24 May 2013. 7 pages, two figures

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Cited by in corpus (9)

• Distribution Amplitudes of Heavy Mesons and Quarkonia on the Light Front
• Modeling interactions of photons with pseudoscalar and vector mesons
• Pion to photon transition form factors with basis light-front quantization
• Pseudoscalar mesons with symmetric bound state vertex functions on the light front
• Systematic twist expansion of $({\eta }_c,{\eta }_b)\to {\gamma }^{\ast }\gamma$ transition form factors in light-front quark model
• Chiral anomaly and the pion properties in the light-front quark model
• Electromagnetic spin-1 form-factor free of zero-modes
• Radial excitation of light mesons and the $\gamma {\gamma }^{\ast }\to {\pi }^0$ transition form factor
• Pion observables calculated in Minkowski and Euclidean spaces with Ansätze for quark propagators