Identifying the ${\mathrm{\Lambda }}_b(6146{)}^0$ and ${\mathrm{\Lambda }}_b(6152{)}^0$ as $D$-wave bottom baryons

We study the ${\mathrm{\Lambda }}_b(6146{)}^0$ and ${\mathrm{\Lambda }}_b(6152{)}^0$ recently observed by LHCb using the method of QCD sum rules within the framework of heavy quark effective theory. Our results suggest that they can be interpreted as $D$-wave bottom baryons of $J^P=3\mathrm{/}{2}^{+}$ and $5\mathrm{/}{2}^{+}$ respectively, both of which contain two $\lambda$-mode excitations. We also investigate other possible assignments containing $\rho$-mode excitations. We predict masses of their strangeness partners to be $m_{{\mathrm{\Xi }}_b(3\mathrm{/}{2}^{+})}=6.26_{-0.14}^{+0.11}$ GeV and $m_{{\mathrm{\Xi }}_b(5\mathrm{/}{2}^{+})}=6.26_{-0.14}^{+0.11}$ GeV with the mass splitting $\Delta M = 4.5^{+1.9}_{-1.5}$ MeV, and propose to search for them in future LHCb and CMS experiments.