Observations of the Cabibbo-Suppressed decays $\Lambda_{c}^{+}\to n\pi^{+}\pi^{0}$, $n\pi^{+}\pi^{-}\pi^{+}$ and the Cabibbo-Favored decay $\Lambda_{c}^{+}\to nK^{-}\pi^{+}\pi^{+}$

TL;DR

This paper reports the first observation and measurement of branching fractions for specific Cabibbo-suppressed and favored decays of the $\Lambda_c^+\$ baryon using electron-positron collision data collected by BESIII, providing new insights into charm baryon decays.

Contribution

It presents the first observation and precise measurement of branching fractions for three $\Lambda_c^+\$ decay modes, including both Cabibbo-suppressed and favored channels.

Findings

First observation of $\Lambda_c^+ o n ext{ } ext{pi}^+ ext{ } ext{pi}^0$ decay.

Branching fraction of $\Lambda_c^+ o n ext{ } ext{pi}^+ ext{ } ext{pi}^- ext{ } ext{pi}^+$ measured as (0.45±0.07±0.03)%.

Branching fraction of $\Lambda_c^+ o n ext{ } K^- ext{ } ext{pi}^+ ext{ } ext{pi}^+$ measured as (1.90±0.08±0.09)%.

Abstract

Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 $\rm{{fb}^{-1}}$, collected by the BESIII detector in the energy region between $4600$ MeV and $4699$ MeV, we report the first observations of the Cabibbo-suppressed decays $\Lambda_c^+\to n\pi^+\pi^0$, $\Lambda_c^+\to n\pi^+\pi^-\pi^+$, and the Cabibbo-favored decay $\Lambda_c^+\to nK^-\pi^+\pi^+$ with statistical significances of $7.9\sigma$, $7.8\sigma$, and $>10\sigma$, respectively. The branching fractions of these decays are measured to be $\mathcal{B}(\Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{0})=(0.64\pm0.09\pm0.02)\%$, $\mathcal{B}(\Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{-}\pi^{+})=(0.45\pm0.07\pm0.03)\%$, and $\mathcal{B}(\Lambda_{c}^{+}\rightarrow nK^{-}\pi^{+}\pi^{+})=(1.90\pm0.08\pm0.09)\%$, where the first uncertainties are statistical and the second are systematic. We find that the branching fraction of the decay $\Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{0}$ is about one order of magnitude higher than that of $\Lambda_{c}^{+}\rightarrow n\pi^{+}$.