Year: 2026
Type: preprint
Abstract: Motivated by the recent BESIII measurement, we revisit the $Λ_c^+\to nπ^+η$ decay within the chiral unitary approach, including internal and external $W$-emission mechanisms and final-state interactions. The $a_0(980)^+$ and $N(1535)^{0,+}$ resonances are dynamically generated by meson--meson and meson--baryon interactions, respectively. With the relative weight of internal to external emission fixed at $1/3$, $2/3$, and $1$, all three scenarios reasonably describe the measured $π^+η$ invariant mass distribution, but yield different fractions for the $a_0(980)$ contribution, and the fraction obtained for $γ=2/3$ and $1$ are numerically below the experimental upper limit. The $a_0(980)$ contribution exhibits a threshold cusp, modified by coherent interference in the total spectrum. Its modest prominence, together with the limited statistical precision and coarse binning, offers a plausible explanation for the absence of a clear experimental signal. We also predict the $ηn$ and $π^+n$ invariant mass distributions. Future high-statistics measurements at BESIII, Belle~II, and STCF would enable a joint analysis to constrain the relative production weight and resonance contributions, providing further insight into the nature of the $a_0(980)$ and $N(1535)$.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G4898400350, G8066039166, G8396383697
OpenAlex ID: W7201880263