Abstract
We provide a theoretical update of the calculations of the pi(0)gamma*gamma form factor in the light cone sum rules framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six corrections related to the photon emission at large distances. The results are compared with the calculations of the B -> pi l nu decay and pion ...
Abstract
We provide a theoretical update of the calculations of the pi(0)gamma*gamma form factor in the light cone sum rules framework, including up to six polynomials in the conformal expansion of the pion distribution amplitude and taking into account twist-six corrections related to the photon emission at large distances. The results are compared with the calculations of the B -> pi l nu decay and pion electromagnetic form factors in the same framework. Our conclusion is that the recent BABAR measurements of the pi(0)gamma*gamma form factor at large momentum transfers [B. Aubert et al. (The BABAR Collaboration), Phys. Rev. D 80, 052002 (2009)] are consistent with QCD, although they do suggest that the pion distribution amplitude may have more structure than usually assumed.
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