From Ds → γ in lattice QCD to Bs → μμγ at high q2

• DOI: 10.1007/jhep07(2023)112
• Publication Date: 2023-07-14T15:01:45Z
• Authors: Diego Guadagnoli; Camille Normand; Silvano Simula; Ludovico Vittorio
• Keywords: Vector meson dominance; Vector meson; Lattice (music); Cabibbo–Kobayashi–Maskawa matrix; Pseudoscalar meson; B meson

We use a recent lattice determination of the vector and axial $D_s \to \gamma$ form factors at high squared momentum transfer $q^2$ to infer their $B_s counterparts. To this end, we introduce phenomenological approach summarized as follows. First, describe data with different fit templates motivated by vector-meson dominance, that is expected hold in high-$q^2$ region considered. identify reference ansaetze one or two physical poles, validate against alternative templates. Then, pole residues can be unambiguously related appropriate couplings involving pseudoscalar, mesons concerned, photon -- tri-couplings latter expressed sums over quark magnetic moments, weighed e.m. charges. This description obeys well-defined heavy-quark scaling, allows parametrically scale up case. discuss number cross-checks whole approach, whose validation rests ultimately first-principle determination, e.g. QCD. Finally, our obtained reassess SM prediction $\mathcal{B}(B_s \mu^+ \mu^- \gamma)$ range $\sqrt{q^2} \in [4.2, 5.0]$ GeV, where an experimental measurement awaited.