Eur. Phys. J. C (2023) 83: 524
https://doi.org/10.1140/epjc/s10052-023-11709-2

Regular Article - Theoretical Physics

Pentaquark interpretation of ${\mathrm{\Lambda }}_c$ states in the quark model

¹ Department of Physics, Nanjing Normal University, 210097, Nanjing, Jiangsu, People’s Republic of China
² School of Physics and Electronic Science, Zunyi Normal University, 563006, Zunyi, People’s Republic of China

^d hxhuang@njnu.edu.cn
^e jlping@njnu.edu.cn

Received: 23 March 2023
Accepted: 10 June 2023
Published online: 21 June 2023

Abstract

Motivated by the recent observation of the ${\mathrm{\Lambda }}_c{(2910)}^{+}$ state in the ${\mathrm{\Sigma }}_c{(2455)}^{0,++}{\pi }^{\pm }$ spectrum by the Belle Collaboration, we investigate the explanation of ${\mathrm{\Lambda }}_c$ states within the pentaquark framework using the quark delocalization color screening model (QDCSM). To check for bound states and resonance states, we utilize the real-scaling method. Additionally, we calculate the root mean square of cluster spacing to study the structure of the states and further estimate whether a state is a resonance state or not. Our numerical results show that ${\mathrm{\Lambda }}_c(2910)$ cannot be interpreted as a molecular state, and ${\mathrm{\Sigma }}_c(2800)$ cannot be explained as the ND molecular state with $J^P=1/2^{-}$. However, we find that ${\mathrm{\Lambda }}_c(2595)$ can be interpreted as a molecular state with $J^P={\frac{1}{2}}^{-}$, where the main component is ${\mathrm{\Sigma }}_c\pi$. Similarly, we interpret ${\mathrm{\Lambda }}_c(2625)$ as a molecular state with $J^P={\frac{3}{2}}^{-}$, where the main component is ${\mathrm{\Sigma }}_c^{\ast }\pi$. We also suggest that ${\mathrm{\Lambda }}_c(2940)$ is likely to be interpreted as a molecular state with $J^P=3/2^{-}$, where the main component is $N{D}^{\ast }$. In addition, we predict two new states: a $J^P=3/2^{-}$${\mathrm{\Sigma }}_c\rho$ resonance state with a mass of 3140–3142 MeV, and a $J^P={\frac{5}{2}}^{-}$${\mathrm{\Sigma }}_c^{\ast }\rho$ state with a mass about 3187–3188 MeV.