Distribution Amplitudes of Heavy-Light Mesons

Abstract

A symmetry-preserving approach to the continuum bound-state problem in quantum field theory is used to calculate the masses, leptonic decay constants and light-front distribution amplitudes of empirically accessible heavy-light mesons. The inverse moment of the $B$-meson distribution is particularly important in treatments of exclusive $B$-decays using effective field theory and the factorisation formalism; and its value is therefore computed: ${\lambda }_B(\zeta =2\mathrm{GeV})=0.54(3)$GeV. As an example and in anticipation of precision measurements at new-generation $B$-factories, the branching fraction for the rare $B\to \gamma (E_{\gamma })\ell {\nu }_{\ell }$ radiative decay is also calculated, retaining $1/m_B^2$ and $1/E_{\gamma }^2$ corrections to the differential decay width, with the result ${\Gamma }_{B\to \gamma \ell {\nu }_{\ell }}/{\Gamma }_B=0.47(15)$ on $E_{\gamma }>1.5$GeV.

6 pages, 6 figure, 5 tables