A dispersive estimate of the a₀(980) contribution to hadronic light-by-light scattering in (g-2)_μ

2023/09/03 by Deineka, Oleksandra, Danilkin, Igor, Vanderhaeghen, Marc
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2309.01195

Abstract

A dispersive implementation of the a₀(980) resonance to (g-2)_μ requires the knowledge of the double-virtual S-wave γ^*γ^*→πη/ KK_I=1 amplitudes. To obtain these amplitudes we used a modified coupled-channel Muskhelischvili-Omnès formalism, with the input from the left-hand cuts and the hadronic Omnès function. The latter were obtained using a data-driven N/D method in which the fits were performed to the different sets of experimental data on two-photon fusion processes with πη and KK final states. This yields the preliminary dispersive estimate a_μ^HLbL[a₀(980)]_resc.=-0.46(2)× 10^-11.

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