Scalar meson contributions to a from hadronic light-by-light scattering

• DOI: 10.1016/j.physletb.2018.10.048
• Publication Date: 2018-10-26T09:57:13Z
• Authors: M. Knecht; S. Narison; A. Rabemananjara; D. Rabetiarivony
• Keywords: data analysis method; dispersion relation; QC1-999; Muon; Non perturbative effects; FOS: Physical sciences; f0(980); a0(980); 01 natural sciences; f0(1500); High Energy Physics - Phenomenology (hep-ph); muon; 0103 physical sciences; form factor: parametrization; f0(1370); photon photon --> K anti-K; muon: magnetic moment; K-matrix; Physics; photon photon: scattering; Radiative width; scalar meson; f0(600); coupled channel; [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph]; non perturbative effects; High Energy Physics - Phenomenology; Scalar mesons; [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]; scalar mesons; radiative width; Anomalous magnetic moment; photon photon --> pi pi

Using an effective ��/f_0(500) resonance, which describes the ����-->����and ����-->����scattering data, we evaluate its contribution and the ones of the other scalar mesons to the the hadronic light-by-light (HLbL) scattering component of the anomalous magnetic moment a_��of the muon. We obtain the conservative range of values: \sum_S~a_��^{lbl}\vert_S = -(4.51+- 4.12) 10^{-11}, which is dominated by the ��/f_0(500) contribution ( 50%~98%), and where the large error is due to the uncertainties on the parametrisation of the form factors. Considering our new result, we update the sum of the different theoretical contributions to a_��within the standard model, which we then compare to experiment. This comparison gives (a_��^{\rm exp} - a_��^{SM})= +(312.1+- 64.3) 10^{-11}, where the theoretical errors from HLbL are dominated by the scalar meson contributions.<br/>15 pages, 7 figures, 8 tables, some misprints corrected in Eq. 4.5 which modifies the results in Table 4 and slightly changes the final result<br/>