Mass spectrum of orbitally and radially excited heavy-light mesons in the relativistic quark model

The mass spectrum of orbitally and radially excited states of $B$ and $D$ mesons is calculated in the framework of the relativistic quark model. The expansion in inverse powers of the heavy quark mass is carried out up to first order, while the light quark is treated without expansion. We find that the relativistic treatment of the light quark plays an important role. Different patterns of $P$ level inversion are discussed. The obtained masses of orbitally and radially excited states are in accord with available experimental data and heavy quark symmetry relations.