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Recent measurement of the $\gamma\gamma^\ast$ form factor of the neutral pionin the high $Q^2$ region disagrees with {\em a priori} predictions of QCD-basedcalculations. We comment on existing explanations, and analyze a possibilitythat this discrepancy is not due to poorly understood QCD effects, but is aresult of some new physics beyond the standard model (SM). We show that suchphysics would necessarily involve a new neutral light state with mass close tothe mass of $\pi^0$, and with stronger than $\pi^0$ couplings to heavier SMflavors such as $c$, $\tau$, and $b$. It is found that only the coupling to the$\tau$ lepton can survive the existing constraints and lead to the observedrise of the pion form factor relative to $Q^{-2}$ at high $Q^2$. We performnumerical fits to data and determine the allowed range of masses and couplingsfor such new particles. This range of masses and couplings could also reduce oreliminate the tension between the $e^+e^-$ and $\tau$ decay determinations ofthe hadronic vacuum polarization. Dedicated experimental analysis of $\tau$pair production in association with such new states should provide a conclusivetest of the new physics hypothesis as an explanation to the pion form factorrise. We also comment on the calculations of the pion form factor in the chiralquark model, and point out a possible dynamical origin of the quark mass scaleinferred from the form factor measurement.

The Pion-Photon Transition Form Factor and New Physics in the Tau Sector