Hadronic ligh-by-light contribution to the anomalous magnetic moment of the muon: The role of scalar resonances in a holographic model of {QCD}

We review the evaluation of scalar mesons contribution to the hadronic light-by-light piece of the muon anomalou smagnetic moment, using a holographic model of QCD. We evaluate the contributions ofthelightest, sub-GeV scalarsσ(500), a0(980) and f0(980) and their associated towers of excited states. Our results point at an egative contribution, overwhelmingly dominated by the σ(500)meson, that we estimate at a(HLbL)= µ =−9(2)·10^−11, in very good agreement with recent determinations from dispersive analyses.