Search for diphoton decays of exotic scalars at BaBar

We report on a search in e+e− annihilations for new π0-like particles produced in association with a τ-lepton pair. These objects, with a similar mass and similar decay modes to π0 mesons, could provide an explanation for the non-asymptotic behavior of the pion-photon transition form factor measured by the BaBar Collaboration. No significant signal is observed, and limits on the production cross section at the level of 73 fb−1 or 370 fb−1, depending on the model parameters, are determined at 90% confidence level. These upper limits lie below the cross section values needed to explain the BaBar form factor data.