Using a sample of $(2712.4 \pm 14.3)\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector, we perform a search for the isospin-violating decays $\chi_{cJ}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.}$ $(J=0,1,2)$ and $\eta_c\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.}$. No significant signal for the $\chi_{cJ}$ or $\eta_c$ is observed in the $\Lambda\bar{\Sigma}^{0}$ invariant mass distribution. The upper limits on the branching fractions at the $90\%$ confidence level are determined to be $$\mathcal{B}(\chi_{c0}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.5\times10^{-6},$$ $$\mathcal{B}(\chi_{c1}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.6\times10^{-6},$$ $$\mathcal{B}(\chi_{c2}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.7\times10^{-6},$$ and $$\mathcal{B}(\eta_c\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<6.2\times10^{-5},$$ all measured for the first time.
Search for the isospin-violating decays 𝜒𝑐𝐽→ΛΣ0bar+c.c. and 𝜂𝑐→ΛΣ0bar+c.c.
Garzia, I.;Melendi, F. M.;
2026
Abstract
Using a sample of $(2712.4 \pm 14.3)\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector, we perform a search for the isospin-violating decays $\chi_{cJ}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.}$ $(J=0,1,2)$ and $\eta_c\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.}$. No significant signal for the $\chi_{cJ}$ or $\eta_c$ is observed in the $\Lambda\bar{\Sigma}^{0}$ invariant mass distribution. The upper limits on the branching fractions at the $90\%$ confidence level are determined to be $$\mathcal{B}(\chi_{c0}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.5\times10^{-6},$$ $$\mathcal{B}(\chi_{c1}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.6\times10^{-6},$$ $$\mathcal{B}(\chi_{c2}\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<1.7\times10^{-6},$$ and $$\mathcal{B}(\eta_c\to\Lambda\bar{\Sigma}^{0}+\mathrm{c.c.})<6.2\times10^{-5},$$ all measured for the first time.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
