2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/148055Mass splitting between axial and vector $\bar{Q}q$ mesons is considered within the standard QCD sum rules. In agreement with the first experimental data on the $B_1$ meson ($J^P =1^{+}$) we find that the splitting for B is about the same as for D and show that $1/m_Q$ corrections to the meson masses are small.5 pages, Latex, 6 figures in one uuencoded compressed postsript file (replacing corrupt file originally submitted)High Energy Physics - Phenomenologytext