The dynamically generated $N(1535)$ state in the $Λ_c^+ \to p\bar{K}^0 π^0$ decay

TL;DR

The paper addresses the nature of the N(1535) resonance and its role in the decay Λ_c^+ → p K0bar π^0. It adopts a chiral unitary framework to dynamically generate N(1535) from coupled-channel meson-baryon interactions and supplements this with nearby resonances, fitting to Belle invariant-mass distributions and Dalitz plots. The results show that the N(1535) peak around 1510 MeV in the π^0 p spectrum is naturally reproduced by the dynamical mechanism, while the inclusion of N(1650), K*(892), and K0*(1430) captures additional structures; an extended fit including N(1440) and Σ(1750) markedly improves the description (χ^2/d.o.f. ≈ 2.65). Overall, the work supports a molecular-like, dynamically generated N(1535) and highlights the importance of multiple resonances in shaping Λ_c^+ decays, with implications for future partial-wave analyses and tests of isospin symmetry in non-factorizable charmed-baryon processes.

Abstract

We present a theoretical analysis of the process $Λ_c^+ \to p\bar{K}^0 π^0$ within the chiral unitary approach, with particular emphasis on the dynamically generated $N(1535)$ resonance. In addition to $N(1535)$, our model incorporates contributions from other intermediate resonances including $N(1650)$, $K^*(892)$, $K_0^*(1430)$, $N(1440)$, and $Σ(1750)$. The calculated invariant mass distributions and Dalitz plot are in good agreement with the recent Belle measurements. Our analysis highlights the crucial role of $N(1535)$ state in this decay channel and supports its interpretation as a dynamically generated state arising from coupled-channel meson-baryon interactions.

Figures (6)

• Figure 1: Quark level diagram for the $\Lambda_c^+\to\bar{K}^0PB$ with hadronization of the $uud$ pair.
• Figure 2: Hadron-level diagrams for $\Lambda_c^+ \to p\bar{K}^0 \pi^0$ decay, including the tree level (a) and final state interactions (b). The blob represents the meson-baryon scattering amplitude $t_{MB\to\pi^0 p}$.
• Figure 3: Resonance contributions to $\Lambda_c^+ \to p\bar{K}^0 \pi^0$: (a) $N(1650)$ production, and (b) $K^*(892)/K_0^*(1430)$ production.
• Figure 4: $\pi^0p$ (a), $\bar{K}^0\pi^0$ (b), and $p\bar{K}^0$ (c) invariant mass distributions of the process $\Lambda^+_c\to p\bar{K}^0\pi^0$ with the fitted parameters of Model A. Black data points with error bars labeled by "Belle data" represent the Belle data taken from Ref. Belle:2025voy, and solid-red curves labeled by "Total" show the total theoretical results. In addition, we have also presented the contributions from the $N(1650)$, $K^*(892)$, and $K_0^*(1430)$, which are labeled by $N(1650)$, $K^*(892)$, and $K_0^*(1430)$, respectively.
• Figure 5: Same as Fig. \ref{['fig:dgdm-4']} but with the fitted parameters of Model B including the $N(1440)$ and $\Sigma(1750)$ contributions.