The heavy-quark effective theory is developed on the light front. Based on this effective theory, a light-front heavy-meson bound state with definite spin and parity is constructed. Within the effective theory, the Isgur-Wise function is derived in terms of the asymptotic light-front bound state amplitudes in the limit ${\mathit{m}}_{\mathit{Q}}$→∞; the result is a general expression for arbitrary recoil velocities. With the asymptotic form of the BSW amplitudes, the Isgur-Wise function is given by ξ(v⋅v′)=1/v⋅v′. The slope at the zero-recoil point is ${\mathrm{\rho }}^2$=-ξ′(1)=1, in excellent agreement with the recent CLEO result of ${\mathrm{\rho }}^2$=1.01±0.15±0.09.

• Received 21 March 1995

DOI:https://doi.org/10.1103/PhysRevD.52.2915