Theory Seminar - De-Liang Yao

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Speaker: De-Liang Yao

Title: Dispersive analysis of the scalar form factors in semileptonic decays

Abstract: The form factors in the semileptonic decays of heavy B/D meson decays can be represented by dispersion relations, which build an elegant bridge to communicate dynamical information from scattering regions. By fitting to the lattice QCD data on the form factors, the subtraction constants in the dispersive representations can be determined such that the form factors in the whole kinematical region are established. As byproducts, Cabibbo–Kobayashi–Maskawa elements can also be extracted with form-factor values at $q^2=0$. In this talk, I will first present a study of heavy-to-light scalar form factors with Muskhelishvili–Omnès dispersion relations, and then introduce a new parametrization of the form factors in $\bar{B}\to D\ell^-\bar{\nu}_\ell$ decays.