BaBar and Belle Measurements of the γγ⁎→π0 Transition Form Factor and Chiral Anomaly

The BaBar measurements of the γγ⁎→π0 transition form factor F(Q2 show that Q2F(Q2) rises steadily with Q2 and at 34 GeV2 is more than 50% above the perturbative QCD(pQCD) prediction. In this talk, I would like to discuss a recent work on the chiral anomaly effects in the γγ⁎→π0 transition form factor F(Q2) at large momentum transfer squared Q2. Using PCAC and the Adler-Bell-Jackiw chiral anomaly triangle graph, we find that, F(Q2) at large Q2 behaves as (m2Q2)×(ln(Q2/m2))2 and is in striking agreement with the BaBar data with m=135MeV which also reproduces very well the CLEO data at lower Q2. The new Belle measurements could also be fitted with m=120MeV.