Complete determination of SU(3)F amplitudes and strong phase in Λ

Abstract

The BESIII collaboration has recently reported the first time measurement of the decay asymmetry α(Λc+→Ξ0K+)=0.01±0.16(stat)±0.03(syst) and also a sizable phase shift of δP−δS=−1.55±0.25 or 1.59±0.25 between S- and P-wave amplitudes. This implies significant strong phase shifts in the decay amplitudes. The strong phases indicate the existence of rescattering or loop effects, which are challenging to calculate due to nonperturbative effects. By employing the flavor SU(3)F symmetry and applying the Körner-Pati-Woo theorem to reduce the number of parameters, we find that the current data already allow us to obtain, for the first time, model-independent decay amplitudes and their strong phases. The establishment of the existence of sizable strong phases opens a window for future investigations into CP violation. In our fit, a notable discrepancy emerges in the branching ratio of Ξc0→Ξ−π+. The direct relationship between Γ(Λc+→Λe+νe) and Γ(Ξc0→Ξ−e+νe), along with newly discovered SU(3)F relations, collectively suggests an underestimation of B(Ξc0→Ξ−π+) in experimental findings. Published by the American Physical Society 2024