2024/10/16 by Oleksandra Deineka, Igor Danilkin, Deineka, Oleksandra +3 · 1 citation
Mathematics · #Advanced Harmonic Analysis Research #Advanced Mathematical Physics Problems #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)
paper · pdf · doi:10.48550/arxiv.2410.12894
openalex publication_date 2024/10/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A dispersive implementation of the a0(980) resonance to (g-2)μ requires the knowledge of the double-virtual S-wave γ^*γ^*→πη/ K K(I=1) amplitudes. To obtain these amplitudes, we used a modified coupled-channel Muskhelishvili-Omnes formalism, with input from the left-hand cuts and the hadronic Omnes matrix. The latter was derived using a data-driven N/D method, where the hadronic left-hand cuts were approximated via a conformal expansion. Due to the absence of direct hadronic data in the πη channel, the expansion coefficients were fitted to various experimental data sets on two-photon fusion processes with πη and K K final states. The resulting dispersive estimate for the a0(980) contribution to (g-2)μ is aμHLbL[a0(980)]resc.=-0.43(1)(2)× 10-11, which presents an order of magnitude improvement in precision over the narrow resonance approximation.