European Physical Journal C: Particles and Fields (Jul 2021)

Hadronic light-by-light contribution to $$(g-2)_\mu $$ ( g - 2 ) μ from lattice QCD: a complete calculation

  • En-Hung Chao,
  • Renwick J. Hudspith,
  • Antoine Gérardin,
  • Jeremy R. Green,
  • Harvey B. Meyer,
  • Konstantin Ottnad

DOI
https://doi.org/10.1140/epjc/s10052-021-09455-4
Journal volume & issue
Vol. 81, no. 7
pp. 1 – 27

Abstract

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Abstract We compute the hadronic light-by-light scattering contribution to the muon $$g-2$$ g - 2 from the up, down, and strange-quark sector directly using lattice QCD. Our calculation features evaluations of all possible Wick-contractions of the relevant hadronic four-point function and incorporates several different pion masses, volumes, and lattice-spacings. We obtain a value of $$a_\mu ^{\text {Hlbl}}= 106.8(15.9) \times 10^{-11}$$ a μ Hlbl = 106.8 ( 15.9 ) × 10 - 11 (adding statistical and systematic errors in quadrature), which is consistent with current phenomenological estimates and a previous lattice determination. It now appears conclusive that the hadronic light-by-light contribution cannot explain the current tension between theory and experiment for the muon $$g-2$$ g - 2 .