On the widths of η(1295) and η(1405/1475)

2023/02/02 by Cheng, Yin, Qiu, Lin, Zhao, Qiang
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2302.01210

Abstract

Based on the assignment of the first radial excitation states of the isoscalar pseudoscalars for η(1295) and η(1405/1475), we investigate their three-body and four-body decay contributions to the total widths. In agreement with our previous studies we find that the triangle singularity (TS) mechanism arising from the intermediate K^*K rescatterings by exchanging a kaon or pion plays a crucial role in both KKπ and ηππ channels. For the η_X (η_X stands for η(1295) and η(1405/1475)) decays into KKπ, we find that although the transition η_X→ K^*K+c.c.→ KKπ is the dominant tree-level process, the productions of the intermediate Kκ+c.c. and a₀(980)π are strongly enhanced by the TS mechanism. For the η_X decays into ηππ, we find that the production of the intermediate a₀(980)π via the triangle transition is the dominant one for η(1295) partly because of the large η(1295)K^*K coupling. In contrast, the tree-level and triangle loop contributions are compatible and dominant in the η(1405/1475) decays into ηππ. It shows that a combined analysis is useful for disentangling the underlying dynamics for these two states.

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