Short-distance HLbL contributions to the muon anomalous magnetic moment beyond perturbation theory

• DOI: 10.1007/jhep10(2020)203
• Publication Date: 2020-10-31T04:39:11Z
• Authors: Johan Bijnens; Nils Hermansson-T...; Laetitia Laub; Antonio Rodríguez...
• Keywords: 530 Physics; FOS: Physical sciences; QC770-798; 01 natural sciences; High Energy Physics - Phenomenology; High Energy Physics - Phenomenology (hep-ph); Nonperturbative Effects; Nuclear and particle physics. Atomic energy. Radioactivity; Perturbative QCD; 0103 physical sciences; Precision QED

AbstractThe hadronic light-by-light contribution to the muon anomalous magnetic moment depends on an integration over three off-shell momenta squared ($$ {Q}_i^2 $$Qi2) of the correlator of four electromagnetic currents and the fourth leg at zero momentum. We derive the short-distance expansion of this correlator in the limit where all three$$ {Q}_i^2 $$Qi2are large and in the Euclidean domain in QCD. This is done via a systematic operator product expansion (OPE) in a background field which we construct. The leading order term in the expansion is the massless quark loop. We also compute the non-perturbative part of the next-to-leading contribution, which is suppressed by quark masses, and the chiral limit part of the next-to-next-to leading contributions to the OPE. We build a renormalisation program for the OPE. The numerical role of the higher-order contributions is estimated and found to be small.