  We present the mass formula for heavy-light charm meson for one loop, using
heavy quark effective theory. Formulating an effective Lagrangian, the masses
of the ground state heavy mesons have been studied in the heavy quark limit
including leading corrections from finite heavy quark masses and nonzero light
quark masses using a constrained fit for the eight equation having eleven
parameters including three coupling constants g, h and g'. Masses determined
from this approach is fitted to the experimentally known decay widths to
estimate the strong coupling constants, showing a better match with available
theoretical and experimental data
