Preliminary cross sections for \gamma p \rightarrow \pi^+ \pi^0 n reaction were measured using the CEBAF Large Acceptance Spectrometer (CLAS) with tagged photon energies between 0.5 and 2.4 GeV. The \pi^+ was detected using the time-of-flight and tracking systems. The \pi^0 was detected via reconstruction of the invariant mass of its two decay photons, which were detected by an electromagnetic calorimeter. The presence of the neutron was inferred via missing mass in the process \gamma p \rightarrow \pi^+ \pi^0 X. From these cross sections measurement, the \gamma \rightarrow 3\pi structure function (F^3\pi) can be extracted at low t, and its momentum dependence can be evaluated. In the chiral limit, F^3\pi is related to the \pi^0 \rightarrow 2\gamma amplitude. Within the context of the chiral anomaly, which successfully predicts the decay of \pi^0, the \gamma \rightarrow 3\pi vertex can be used to evaluate the validity of chiral symmetry in QCD.

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