Physicists set new limits on exotic particle production in rare collisions
Researchers using China's BESIII detector searched for evidence of a rare particle-creation process but found no signal, establishing the first upper bounds on how often it occurs. The null result helps refine models of exotic matter and guides where future particle physics experiments should focus resources.
Originaltitel: Search for the e + e − → ϕχ <sub>c1</sub>(3872) process at BESII
<p>Based on 368.5 pb<sup>−1</sup> of 𝑒+𝑒− collision data collected at center-of-mass energies 4.914 and 4.946 GeV by the BESIII detector, the 𝑒+𝑒− →𝜙𝜒𝑐1(3872) process is searched for the first time. No significant signal is observed and the upper limits at the 90% confidence level on the product of the Born cross section 𝜎(𝑒<sup>+</sup>𝑒<sup>−</sup> →𝜙𝜒𝑐1(3872)) and the branching fraction ℬ[𝜒𝑐1(3872) →𝜋<sup>+</sup>𝜋<sup>−</sup>𝐽/𝜓] at 4.914 and 4.946 GeV are set to be 0.85 and 0.96 pb, respectively. These measurements provide useful information for the production of the 𝜒<sub>𝑐1</sub>(3872) at 𝑒<sup>+</sup>𝑒<sup>−</sup> colliders and deepen our understanding about the nature of this particle.</p>