$\Lambda_b(6146)^0$ state newly observed by LHCb

Abstract

We study the bottom $\Lambda_b(6146)^0$ baryon, newly discovered by the LHCb Collaboration. By adopting an interpolating current of $(L_{\rho}, L_{\lambda})=(0,2)$ type and $D$-wave nature with spin-parity quantum numbers $J^P=\frac{3}{2}^+$ for this heavy bottom baryon, we calculate its mass and residue. Using these spectroscopic parameters, we also investigate its dominant decays $\Lambda_b(6146)^0\rightarrow\Sigma_b\pi$ and $\Lambda_b(6146)^0\rightarrow\Sigma^*_b\pi$ and estimate the width of $\Lambda_b(6146)^0$ obtained via these channels. The obtained mass, $m_{\Lambda_b}=(6144\pm 68)$~MeV is in accord nicely with the experimental data. The width obtained via the dominant channels is also consistent with the experimental data of LHCb collaboration. We calculate the spectroscopic parameters and the same decay channels for the $c$-partner of $\Lambda_b(6146)^0$ state, namely $\Lambda_c(2860)^+$, as well. We compare the obtained results with the existing theoretical predictions as well as experimental data. The results indicate that the state $\Lambda_b(6146)^0$ and its charmed-partner $\Lambda_c(2860)^+$ can be considered as $1D$-wave baryons with $J^P=\frac{3}{2}^+$.