Resummation of (−b0αs)n corrections to the photon-meson transition form factor γ∗ + γ → π0 Original Research Article

We have resummed all the (−b0αs)n contributions to the photon-meson transition form factor Fπγ. To do this, we have used the assumption of ‘naive non-abelianization’ (NNA). Within NNA, a series in (Nƒαs)n is interpreted as a series in (−b0αs)n by means of the restoration of the full first QCD β-function coefficient −b0 by hand. We have taken into account corrections to the leading order coefficient function and to the evolution of the distribution function. Due to conformal symmetry constraints, it is possible to find the eigenfunctions of the evolution kernel. It turns out that the non-diagonal corrections are small, and neglecting them we obtained a representation for the distribution function with multiplicatively renormalized moments. For a simple shape of the distribution function, which is close to the asymptotic shape, we find that the radiative correction decrease the LO by 30%, and the uncertainty in the resummation lies between 10% and 2% for Q2 between 2 and 10 GeV2.