2025/02/05 by Guevara, Adolfo, Guo, Feng-Kun, Jing, Hao-Jie
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2502.02837
We propose a novel approach for extracting symmetry breaking effects from symmetry conserved three-body decays. The method is based on mapping the Dalitz plot to a unit disk, and the difference of the disk distributions of two related decays isolates purely symmetry breaking effects. We demonstrate this method by extracting the fundamental parameter Q, an isospin breaking ratio of light quark masses defined as Q2≡ (ms2- m2)/(md2-mu2) with m the average of up and down quark masses, from the decays η'→ηπ+π- and η'→ηπ0π0. With the Dalitz plot distributions for these two decays reported by BESIII, we obtain Q=22.3±0.7, which is consistent with previous determinations and has a comparable uncertainty. With the full BESIII data set, which is eight times larger than the one used here, a significantly more precise determination of Q will be achievable. This promising and novel method can be generalized to other three-body decays to extract symmetry breaking effects.