Measurement of γγ⁎→π0 transition form factor at Belle

We report a measurement of the exclusive π0 production in the process of e+e− scattering in kinematic region where the π0 and the final-state electron or positron are detected (i.e., tagged). We use 759 fb−1 data sample recorded with the Belle detector at the KEKB asymmetric-energy e+e− collider to measure the γγ⁎→π0 transition form factor F(Q2) in the momentum transfer region 4 GeV2⩽Q2⩽40 GeV2. The reported values of Q2|F(Q2)| agree well with previous measurements at Q2⩽9 GeV2, are reasonably consistent with recent results reported by the BaBar experiment but do not support their hypothesis of the rapid increase of Q2|F(Q2)| at higher Q2 values.