Meson Decay Constants from Isospin Mass Splittings in the Quark Model

Abstract

Decay constants of $D$ and $B$ mesons are estimated within the framework of a heavy-quark approach using measured isospin mass splittings in the $D$, $D^{\ast }$, and $B$ states to isolate the electromagnetic hyperfine interaction between quarks. The values $f_D=(262\pm 29)$ MeV and $f_B=(160\pm 17)$ MeV are obtained. Only experimental errors are given; possible theoretical ambiguities, and suggestions for reducing them, are noted.

7 pages, LaTeX, EFI-92-31