Canonical interpretation of the newly observed ${\mathrm{\Lambda }}_b(6146{)}^0$ and ${\mathrm{\Lambda }}_b(6152{)}^0$ via strong decay behaviors

Stimulated by the newly observed ${\mathrm{\Lambda }}_b(6146{)}^0$ and ${\mathrm{\Lambda }}_b(6152{)}^0$ resonances, we investigate the strong decays of the low-lying singly bottom baryons within the quark pair creation model. Considering their masses and decay modes, we tentatively assign these states as the $\lambda$-mode ${\mathrm{\Lambda }}_b(2S)$, ${\mathrm{\Lambda }}_b(1D)$, ${\mathrm{\Sigma }}_b(2S)$, and ${\mathrm{\Sigma }}_b(1P)$ states and then estimate their strong decay widths. Compared with the experimental total widths and decay modes measured by the LHCb Collaboration, the ${\mathrm{\Lambda }}_b(6146{)}^0$ and ${\mathrm{\Lambda }}_b(6152{)}^0$ can be reasonably clarified into the $J^P=5/2^{+}$ and $J^P=3/2^{+}$ ${\mathrm{\Lambda }}_b(1D)$ states, respectively, while other canonical assignments are disfavored. Other low-lying bottom states are also presented, where various narrow states may have good potential to be observed in future LHCb experiments.

Figure 1

The baryon decay process $A\to B+C$ in the ${}^3{P}_0$ model.

Figure 2

The dependence on the harmonic oscillator parameter ${\alpha }_{\rho }$ of the initial states. The green bands stand for the measured total decay widths with errors.

Figure 3

The total decay widths of various assignments as functions of the mixing angle $\theta$ in the range $-30°–30°$. The red solid lines are the $|P3/2^{-}{⟩}_1$ states, and the blue dashed curves correspond to the $|P3/2^{-}{⟩}_2$ states. The green bands stand for the measured total decay widths with errors.