Doubly heavy baryonsΩQQ′versusΞQQ′in sum rules of nonrelativistic QCD

In the framework of two-point sum rules of nonrelativistic QCD, the masses and couplings of doubly heavy baryons to the corresponding quark currents are evaluated taking into account Coulomb-like corrections in the system of a doubly heavy diquark as well as the contribution of nonperturbative terms determined by the quark, gluon, mixed condensates, and the product of gluon and quark condensates. The introduction of nonzero light quark mass destroys the factorization of baryon and diquark correlators even at the perturbative level and provides the better convergency of sum rules. We estimate the difference $M_{\Omega }-M_{\Xi }=100\mathrm{}\pm 30\mathrm{MeV}.$ The ratio of baryonic constants $|Z_{\Omega }{|}^2/|Z_{\Xi }{|}^2$ is equal to $1.3\pm 0.2$ indicating the violation of $\mathrm{SU}\left(3\right)\mathrm{}$ flavor symmetry for the doubly heavy baryons.