2024/11/10 by Lin, Tian, Mattia Bruno, Xu Feng +9 · 1 citation
Physics and Astronomy · Computer Science · #Particle physics theoretical and experimental studies #Computational Physics and Python Applications #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2411.06349
We develop a method to compute the pion transition form factor directly at arbitrary space-like photon momenta and use it to determine the π0-pole contribution to the hadronic light-by-light scattering in the anomalous magnetic moment of the muon. The calculation is performed using eight gauge ensembles generated with 2+1 flavor domain wall fermions, incorporating multiple pion masses, lattice spacings, and volumes. By introducing a pion structure function and performing a Gegenbauer expansion, we demonstrate that about 98% of the π0-pole contribution can be extracted in a model-independent manner, thereby ensuring that systematic effects are well controlled. After applying finite-volume corrections, as well as performing chiral and continuum extrapolations, we obtain the final result for the π0-pole contribution to the hadronic light-by-light scattering in the muon's anomalous magnetic moment, aμπ0-pole=61.2(1.7)× 10-11, and the π0 decay width, Γπ0→ γγ=7.60(27) eV.