Physicists Measure Exotic Particle Decay With 10x Better Precision
Researchers used 10 billion particle collision events to measure how a J/psi particle decays into other particles with unprecedented accuracy. The findings validate theoretical physics models and could refine our understanding of fundamental forces—relevant for anyone developing quantum technologies or particle detection systems.
Originaltitel: Study of the Magnetic Dipole Transition of 𝐽/𝜓 → 𝛾𝜂𝑐 via 𝜂𝑐 → 𝑝¯𝑝
<p>Using (10.087±0.044)×109 𝐽/𝜓 events collected with the BESIII detector at the 𝑒+𝑒− BEPCII collider, we present the first amplitude analysis of 𝐽/𝜓 → 𝛾𝑝¯𝑝 with the 𝑝¯𝑝 invariant mass in the 𝜂𝑐mass region [2.70,3.05] GeV/𝑐2. The product branching fraction ℬ(𝐽/𝜓 → 𝛾𝜂𝑐)×ℬ(𝜂𝑐 → 𝑝¯𝑝) is determined to be (2.11±0.02stat±0.07syst)×10−5 with precision improved by 1 order of magnitude. Combining with the product branching fractions ℬ(𝜂𝑐 → 𝑝¯𝑝)×ℬ(𝜂𝑐 → 𝛾𝛾) and ℬ(𝐽/𝜓 → 𝛾𝜂𝑐)×ℬ(𝜂𝑐 → 𝛾𝛾), the branching fractions of ℬ(𝐽/𝜓 → 𝛾𝜂𝑐) and ℬ(𝜂𝑐 → 𝛾𝛾) are calculated to be (2.29±0.01stat±0.04syst±0.18opbf)% and (2.28±0.01stat±0.04syst±0.18opbf)×10−4, respectively, which are consistent with the latest lattice quantum chromodynamics calculations. Here, opbf is the uncertainty from the other product branching fractions used in the calculation.</p>