String point of view for heavy-light mesons*

Abstract

An approximate rotational symmetry of a heavy-light meson is viewed from a string picture. Using a simple string configuration, we derive a formula, (M–mc)2 = πσL, whose coeffcient of the r.h.s. is just 1/2 of that of a light meson with two light quarks. A numerical plot is obtained for D mesons of experimental data as well as several theoretical models, which shows good agreement with this formula.