On the precision of a data-driven estimate of the pseudoscalar-pole contribution to hadronic light-by-light scattering in the muong−2

Abstract

Abstract. The evaluation of the numerically dominant pseudoscalar-pole contribution to hadronic light-bylight scattering in the muon g − 2 involves the pseudoscalar-photon transition form factor F Pγ * γ * (−Q 2 1 , −Q 2 2 ) with P = π 0 , η, η and, in general, two off-shell photons with spacelike momenta Q 2 1,2 . We determine which regions of photon momenta give the main contribution for hadronic light-by-light scattering. Furthermore, we analyze how the precision of future measurements of the single-and double-virtual form factor impacts the precision of a data-driven estimate of this contribution to hadronic light-by-light scattering.

A call for new physics: The muon anomalous magnetic moment and lepton flavor violation

“…(44) and Eq. (47). After computing the coupling constants and matching the vector and axial-vector couplings to the Left-Right charged current, as done above, we obtain,…”

Hadronic light-by-light contribution toaμ: extended Nambu-Jona-Lasinio, chiral quark models and chiral Lagrangians

“…We took the form-factor that was made to fit the then existing data integrated up to 6.66 × 10 −10 All of these are in reasonable agreement, within the errors. Future improvements will come when more experimental results are included as discussed in the talk by Nyffeler [6].…”

“…The hadronic light-by-light-contribution (HLbL) shown in Fig. 1 was discussed in the talks by Procura [3], Cappiello [4], Greynat [5], Nyffeler [6], Lehner [7] and Vanderhaeghen [8].…”

Hadronic light-by-light contribution to $a_μ$: extended Nambu-Jona-Lasinio, chiral quark models and chiral Lagrangians

“…The hadronic light-by-light-contribution (HLbL) shown in Fig. 1 was discussed in the talks by Procura [3], Cappiello [4], Greynat [5], Nyffeler [6], Lehner [7] and Vanderhaeghen [8]. There were also several talks on the underlying formfactors, both theoretically and experimentally.…”