Unveiling the elusive $Σ(1380)$ resonance through coupled-channel dynamics in $Λ_c^+\toηπ^+Λ$ reaction

Abstract

We investigate the $Λ_c^+ \to ηπ^+ Λ$ decay measured by the Belle and BESIII Collaborations, focusing on the possible role of the $Σ(1380)$ state with spin-parity $J^P=1/2^-$. In our theoretical framework, the $Λ(1670)$ and $a_0(980)$ are dynamically generated from meson-baryon and meson-meson final-state interactions, respectively, and the corresponding line shapes of these two states used here are applicable to all relevant hadronic reactions. Furthermore, the contributions from the intermediate $Σ(1385)$ resonance and the possible $Σ(1380)$ state are included explicitly. By comparing the invariant mass and angular distributions obtained with and without the $Σ(1380)$ state, we demonstrate that this state plays an important role in improving the description of the experimental data. We also identify the kinematic regions most sensitive to the possible $Σ(1380)$ contribution. Future high-precision measurements of this process will be instrumental for testing the existence of the $Σ$ state with $J^P=1/2^-$.