Physicists spot unexpected decay pattern that challenges particle physics models
A team using China's BESIII particle detector has observed a rare decay process in charm baryons that contradicts theoretical predictions by a significant margin. The finding suggests unknown forces or particles may be at work, potentially opening new directions for fundamental physics research and detector development.
Originaltitel: First observation of the decay Λ<sub>c</sub><sup>+</sup> → nK<sub>S</sub><sup>0</sup>π<sup>+</sup>π<sup>0</sup>
<p>Based on 4.5 fb<sup>-1</sup> of e<sup>+</sup>e<sup>-</sup> collision data accumulated at center-of-mass energies between 4599.53 and 4698.82 MeV with the BESIII detector, the decay Λ<sub>c</sub><sup>+</sup> → nK<sub>S</sub><sup>0</sup>π<sup>+</sup>π<sup>0</sup> is observed for the first time with a significance of 9.2σ. The branching fraction is measured to be (0.85 ± 0.13 ± 0.03)%, where the first uncertainty is statistical and the second is systematic, which differs from the theoretical prediction based on isospin by 4.4σ. This indicates that there may be resonant contributions or some unknown dynamics in this decay.</p>