Physicists Discover New Particle Decay Pathways at China's Collider
Researchers using China's BESIII detector have identified previously unknown ways that exotic particles decay, potentially revealing hidden structures in matter. The findings advance understanding of particle physics fundamentals that underpin next-generation physics experiments and detector technologies.
Originaltitel: Study of the 𝜒<sub>𝑐𝐽</sub> → Λ¯Λ𝜂′ decays
<p>Using a data sample of (2.712 ±0.014) ×109 𝜓(3686) events collected with the BESIII detector at the BEPCII collider, we investigate the decays 𝜒𝑐𝐽 → Λ¯Λ𝜂′ for 𝐽 =0, 1, 2 via the radiative transition 𝜓(3686) → 𝛾𝜒𝑐𝐽. The decays 𝜒𝑐0,2 →Λ¯Λ𝜂′ are observed for the first time, with statistical significances of 6.7𝜎 and 6.4𝜎, respectively. Evidence for the decay 𝜒𝑐1 → Λ¯Λ𝜂′ is found with a statistical significance of 3.3𝜎. The corresponding branching fractions are measured to be ℬ(𝜒𝑐0 → Λ¯Λ𝜂′) = (7.56 ±1.42 ±0.90) ×10−5, ℬ(𝜒𝑐1 → Λ¯Λ𝜂′) =(1.54 ±0.51 ±0.16) ×10−5, and ℬ(𝜒𝑐2 → Λ¯Λ𝜂′) = (3.03 ±0.61 ±0.29) ×10−5, where the first uncertainties are statistical and the second are systematic. No significant excited Λ baryon states or Λ¯Λ near-threshold enhancements are observed.</p>