Lattice QCD and the two-photon decay of the neutral pion

Abstract

Two-photon decays probe the structure of mesons and represent an important contribution to hadronic light-by-light scattering. For the neutral pion, the decay amplitude tests the effects of the chiral anomaly; for a heavy quarkonium state, it measures the magnitude of its wavefunction at the origin. We rederive the expression of the decay amplitude in terms of a Euclidean correlation function starting from the theory defined on the torus. The derivation shows that for timelike photons the approach to the infinite-volume decay amplitude is exponential in the periodic box size.

18 pages, no figures

References in corpus (5)

• Three particles in a finite volume
• Three-particle scattering amplitudes from a finite volume formalism
• Two Photon Decays of Charmonia from Lattice QCD
• Two-photon decay of the neutral pion in lattice QCD
• The neutral pion decay and the chiral anomaly on the lattice

Cited by in corpus (6)

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• On the Determination of Elastic and Inelastic Nuclear Observables from Lattice QCD
• Formal Developments for Lattice QCD with Applications to Hadronic Systems