Search for the isospin-violating decays 𝜒 𝑐𝐽 → $Λ\bar{Σ}^0$ + c.c. and 𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c.
Using a sample of (2712.4 ± 14.3) × 10 6 𝜓(3686) events collected with the BESIII detector, we perform a search for the isospin-violating decays 𝜒 𝑐𝐽 → $Λ\bar{Σ}^0$ + c.c.(𝐽 = 0,1,2) and 𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c. No significant signal for 𝜒 𝑐𝐽 or 𝜂 𝑐 is observed in the $Λ\bar{Σ}^0$ invariant mass distribution. The upper limits on the branching fractions at the 90% confidence level are set to be ℬ(𝜒 𝑐0 → $Λ\bar{Σ}^0$ + c.c.) < 1.5 × 10 −6 , ℬ(𝜒 𝑐1 → $Λ\bar{Σ}^0$ + c.c.) < 1.6 × 10 −6 , ℬ(𝜒 𝑐2 → $Λ\bar{Σ}^0$ + c.c.) < 1.7 × 10 −6 , and ℬ(𝜂 𝑐 → $Λ\bar{Σ}^0$ + c.c.) < 6.2 × 10 −5 for the first time.
Ablikim, M. [Institute of High Energy Physics] (OR↗