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

Abstract

We study the ${\Lambda }_b(6146{)}^0$ and ${\Lambda }_b(6152{)}^0$ 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 $J^P=3/2^{+}$ and $5/2^{+}$ 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 $m_{{\Xi }_b(3/2^{+})}=6.26_{-0.14}^{+0.11}$ GeV and $m_{{\Xi }_b(5/2^{+})}=6.26_{-0.14}^{+0.11}$ GeV with the mass splitting $\Delta M=4.5_{-1.5}^{+1.9}$ MeV, and propose to search for them in future LHCb and CMS experiments.

Comments: 14 pages, 6 figures, 1 table, revised version