Electromagnetic probes revealing the inner structure of the $\Lambda_c(2940)$

TL;DR

This paper explores the internal structure of the $ ext{Lambda}_c(2940)$ baryon through electromagnetic decay modes, using a molecular state hypothesis and theoretical calculations to guide future experimental investigations.

Contribution

It provides a theoretical analysis of $ ext{Lambda}_c(2940)$ radiative decays based on a molecular model, offering predictions to distinguish its structure.

Findings

Decay width ratios vary with quantum number assumptions

Electromagnetic probes can reveal the baryon's internal structure

Theoretical predictions guide future experimental validation

Abstract

The $\Lambda_c(2940)$, an open-charm baryon discovered in 2006, has sparked interest due to its ``low mass puzzle'', paralleling the $X(3872)$ in the charmoniumlike sector. Both states challenge conventional hadronic interpretations, with the $X(3872)$ understood as a $D^*\bar{D}$ molecular state and the $\Lambda_c(2940)$ hypothesized as a $D^*N$ molecular state. This work investigates the radiative decay modes $\Lambda_c(2940) \to \Lambda_c(2286)\gamma$, $\Lambda_c(2940) \to \Lambda_c(2595)\gamma$, and $\Lambda_c(2940) \to \Lambda_c(2765)\gamma$, analogous to radiative transitions observed in the $X(3872)$. Using the one-boson-exchange model to obtain the $D^*N$ molecular spatial wave function as input, we calculate decay widths and their ratios, finding differences with different quantum number assumptions. Our findings underscore the potential of electromagnetic probes in revealing its nature and highlight the need for dedicated experimental studies to validate these theoretical predictions.