Two-photon decay of the neutral pion in lattice QCD

Understand

We perform non-perturbative calculation of the \pi^0 to {\gamma}{\gamma} transition form factor and the associated decay width using lattice QCD.

• The amplitude for two-photon final state, which is not an eigenstate of QCD, is extracted through an Euclidean time integral of the relevant three-point function.
• We utilize the all-to-all quark propagator technique to carry out this integral as well as to include the disconnected quark diagram contributions.
• The overlap fermion formulation is employed on the lattice to ensure exact chiral symmetry on the lattice.