论文标题
弱辐射性超子衰减在协变性重手性扰动理论中
Weak radiative hyperon decays in covariant baryon chiral perturbation theory
论文作者
论文摘要
弱辐射性超子衰减对于测试强烈的相互作用很重要，并且与对标准模型物理的搜索相关，并且在实验和理论上一直困扰着很长时间。最近更新的分支分数和BESIII协作的$λ\至Nγ$的不对称参数的首次测量进一步加剧了问题，因为现有的预测都无法描述数据。我们在这封信中表明，协变量的重手性扰动理论，其最新测量值的限制可以很好地描述BESIII数据。预测的分支分数和$ξ^ - \toς^-γ$的不对称参数也与实验数据一致。我们注意到，对不对称参数的更精确的测量与$σ^+\至Pγ$相关，这对于测试HARA定理至关重要。我们进一步预测了$σ^0 \至Nγ$的分支分数和不对称参数，其未来的测量可以作为我们对弱辐射超子衰变和协证巴里式手里扰动理论的理解的高度非平凡检查。
Weak radiative hyperon decays, important to test the strong interaction and relevant in searches for beyond the standard model physics, have remained puzzling both experimentally and theoretically for a long time. The recently updated branching fraction and first measurement of the asymmetry parameter of $Λ\to nγ$ by the BESIII Collaboration further exacerbate the issue, as none of the existing predictions can describe the data. We show in this letter that the covariant baryon chiral perturbation theory, with constraints from the latest measurements of hyperon non-leptonic decays, can well describe the BESIII data. The predicted branching fraction and asymmetry parameter for $Ξ^-\toΣ^-γ$ are also in agreement with the experimental data. We note that a more precise measurement of the asymmetry parameter, which is related with that of $Σ^+\to pγ$, is crucial to test Hara's theorem. We further predict the branching fraction and asymmetry parameter of $Σ^0\to nγ$, whose future measurement can serve as a highly nontrivial check on our understanding of weak radiative hyperon decay and on the covariant baryon chiral perturbation theory.
