近日，厄瓜多尔国立理工学院的A. Duenas-Vidal及其研究小组与西班牙萨拉曼卡大学的P. G. Ortega等人合作并取得一项新进展。经过不懈努力，他们详细推导出针对重子的³P₀强衰变模型。相关研究成果已于2025年1月15日在《中国物理C》上发表。

利用³P₀夸克对产生模型，该研究团队详细推导了重子衰变为介子-重子系统的跃迁矩阵。这一分析方法在介子领域已成功应用于[J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)]，研究人员将同一形式主义扩展到重子领域，重点研究Δ(1232)→πN强衰变宽度，因为该反应涉及的所有强子都已非常确定，末态中的两个强子是稳定的且无需进一步分析，所有夸克都是轻夸克因而等价，且该过程的衰变宽度测量得相对准确。

研究人员采用常用的Rayleigh-Ritz变分法求解二体和三体的薛定谔束缚态方程，其中强子的径向波函数用高斯基展开。这样，他们可以将不变矩阵元的表达式与衰变中涉及的强子的均方半径联系起来。他们利用它们的实验测量值，使得仅有真空中的夸克-反夸克对产生强度成为自由参数。

这一参数取自之前关于介子领域强衰变宽度的研究[J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)]，并且所得结果与计算的Δ(1232)→πN衰变宽度的实验结果相符。尽管还需要计算其他重子的强衰变，但在单一组分夸克模型框架内，对重子和介子的强衰变宽度进行统一描述的可行途径可能是可实现的。

最后，这项研究为将新方法应用于奇异强子奠定了基础，即描述重子与介子-重子阈值的耦合，这是被认为负责给原始态提供大重整化或真正动态生成的介子-重子分子的机制之一。

附：英文原文

Title: Detailed derivation of the ³P₀ strong decay model applied to baryons

Author: T. Aguilar, A. Capelo-Astudillo, M. Conde-Correa, A. Duenas-Vidal, P. G. Ortega, J. Segovia

Issue&Volume: 2025-01-15

Abstract: By using the³P₀ pair creation model, we provide a detailed derivation of the transition matrix for a baryon decaying into a meson-baryon system. This analysis was successfully conducted for a meson in [J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)], and we extend the same formalism to the baryon sector, focusing on the Δ(1232)→πN strong decay width because all hadrons involved in the reaction are very well established, the two hadrons in the final state are stable and require no further analysis, all quarks are light and thus equivalent, and the decay width of the process is relatively well measured. Utilizing a very common Rayleigh-Ritz variational method to solve the 2- and 3-body Schdinger bound-state equation in which the hadron’s radial wave functions are expanded in terms of a Gaussian basis, we can relate the expression of the invariant matrix element with the mean-square radii of hadrons involved in the decay. We use their experimental measures in such a way that only the strength of the quark-antiquark pair creation from the vacuum is a free parameter. This is then taken from our previous study on strong decay widths in the meson sector [J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)], and the obtained results are compatible with the experimental results for the calculated Δ(1232)→πN decay width. Despite requiring the calculation of additional baryon strong decays, a feasible avenue towards a unified description of both baryon and meson strong decay widths within a single constituent quark model framework may be attainable. Finally, this research has been developed to lay the foundation for a novel raft of applications to exotic hadrons, i.e., the description of the baryon’s coupling to meson-baryon thresholds, one of the mechanisms that is considered to be responsible for providing either a large renormalization to naive states or genuine dynamically-generated meson-baryon molecules.

DOI: 10.1088/1674-1137/ad8d4c

Source: http://hepnp.ihep.ac.cn/article/doi/10.1088/1674-1137/ad8d4c