Precision evaluation of the $η$- and $η'$-pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon
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| Format: | Preprint |
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2024
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| _version_ | 1866913811496173568 |
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| author | Holz, Simon Hoferichter, Martin Hoid, Bai-Long Kubis, Bastian |
| author_facet | Holz, Simon Hoferichter, Martin Hoid, Bai-Long Kubis, Bastian |
| contents | Next to the $π^0$ pole, $η$ and $η'$ intermediate states give rise to the leading singularities of the hadronic light-by-light tensor, resulting in sizable contributions to the anomalous magnetic moment of the muon $a_μ$. The strength of the poles is determined by the respective transition form factors (TFFs) to two (virtual) photons. We present a calculation of these TFFs that implements a number of low- and high-energy constraints, including the $η^{(\prime)}\toγγ$ decay widths, $η^{(\prime)}\toπ^+π^-γ$ spectra, chiral symmetry for the $η^{(\prime)}\to 2(π^+π^-)$ amplitudes, vector-meson couplings, and asymptotic limits. Crucially, we investigate the role of the leading left-hand singularity generated by the exchange of the $a_2$ tensor meson, yielding, for the first time, an estimate of the associated factorization-breaking corrections. Our final results, $a_μ^{η\text{-pole}}=14.7(9)\times 10^{-11}$ and $a_μ^{η'\text{-pole}}=13.5(7)\times 10^{-11}$, conclude a dedicated effort to evaluate the pseudoscalar-pole contributions to hadronic light-by-light scattering using dispersion relations, amounting to a combined $a_μ^{\text{PS-poles}}=91.2^{+2.9}_{-2.4}\times 10^{-11}$. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2411_08098 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Precision evaluation of the $η$- and $η'$-pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon Holz, Simon Hoferichter, Martin Hoid, Bai-Long Kubis, Bastian High Energy Physics - Phenomenology High Energy Physics - Experiment High Energy Physics - Lattice Nuclear Theory Next to the $π^0$ pole, $η$ and $η'$ intermediate states give rise to the leading singularities of the hadronic light-by-light tensor, resulting in sizable contributions to the anomalous magnetic moment of the muon $a_μ$. The strength of the poles is determined by the respective transition form factors (TFFs) to two (virtual) photons. We present a calculation of these TFFs that implements a number of low- and high-energy constraints, including the $η^{(\prime)}\toγγ$ decay widths, $η^{(\prime)}\toπ^+π^-γ$ spectra, chiral symmetry for the $η^{(\prime)}\to 2(π^+π^-)$ amplitudes, vector-meson couplings, and asymptotic limits. Crucially, we investigate the role of the leading left-hand singularity generated by the exchange of the $a_2$ tensor meson, yielding, for the first time, an estimate of the associated factorization-breaking corrections. Our final results, $a_μ^{η\text{-pole}}=14.7(9)\times 10^{-11}$ and $a_μ^{η'\text{-pole}}=13.5(7)\times 10^{-11}$, conclude a dedicated effort to evaluate the pseudoscalar-pole contributions to hadronic light-by-light scattering using dispersion relations, amounting to a combined $a_μ^{\text{PS-poles}}=91.2^{+2.9}_{-2.4}\times 10^{-11}$. |
| title | Precision evaluation of the $η$- and $η'$-pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment High Energy Physics - Lattice Nuclear Theory |
| url | https://arxiv.org/abs/2411.08098 |