E. Shintani, S. Aoki, S. Hashimoto, T. Onogi, N. Yamada. Pi^0 to two-photon decay in lattice Qcd

Natural Sciences / Physics / Particle physics

Submitted on: Sep 20, 2012, 17:38:01

Description: We calculate the neutral pion ($pi^0$) to off-shell two photon ($gamma^*gamma^*$) transition form factor in lattice QCD. The transition form factor can be extracted from the three-point function of the form (axial-vector)-(vector)-(vector) as a function of off-shell two-photon momentum. Since the axial-anomaly plays an important role in the $pi^0togammagamma$ decay process, we employ the overlap fermion, which preserves the exact chiral symmetery on the lattice. After extrapolating to the chiral and the vanishing photon momentum limit with a fit function based on vector meson dominance (VMD) model, we find that the Adler-Bell-Jackiw anomaly is correctly reproduced. *** Journal reference: PoS LAT2009:246,2009 ***