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The new BABAR data on the pion-photon transition form factor arouses people'snew interests on the determination of pion distribution amplitude. To explainthe data, we take both the leading valence quark state's and the non-valencequark states' contributions into consideration, where the valence quark part upto next-to-leading order is presented and the non-valence quark part isestimated by a phenomenological model based on its limiting behavior at both$Q^2\to 0$ and $Q^2\to\infty$. Our results show that to be consistent with thenew BABAR data at large $Q^2$ region, a broader other than the asymptotic-likepion distribution amplitude should be adopted. The broadness of the piondistribution amplitude is controlled by a parameter $B$. It has been found thatthe new BABAR data at low and high energy regions can be explainedsimultaneously by setting $B$ to be around 0.60, in which the pion distributionamplitude is closed to the Chernyak-Zhitnitsky form.

An Implication on the Pion Distribution Amplitude from the Pion-Photon Transition Form Factor with the New BABAR Data