Comprehensive study of light axial vector mesons with the presence of triangle singularity

We present a systematic study of the productions and decays of light axial vector mesons with J(PC) = 1(++/-) in charmonium decays. In the quark-model scenario, the two axial vector nonets are connected to each other by the Gell-Mann-Okubo mass relation through the mixing between two K-1 states [i.e., K-1(1270) and K-1(1400)] with configurations of P-3(1) and P-1(1). The mixing angles between f(1) and f(1)' [i.e., f(1)(1285) and f(1)(1420)] and between h(1) and h(1)' [i.e., h(1)(1170) and h(1)(1415)] can be reliably constrained. We then introduce the intermediate K*(K) over bar + c.c. meson loop transitions in the description of the productions and decays of these axial vector mesons. The presence of the nearby S-wave K*(K) over bar + c.c., to which these axial vector mesons have strong coupling strengths, turns out to be crucial for understanding many puzzling questions related to their production and decay. This is because the S-wave K*(K) over bar + c.c. rescatterings by the kaon exchange satisfy the triangle singularity (TS) condition in some of these cases and the TS mechanism can introduce special interference effects into the exclusive decays of these light axial vector mesons.

Automated summary

In this study, a systematic analysis of the production and decay of light axial vector mesons with J(PC) = 1(++/-) in charmonium decays was conducted. It was found that the presence of nearby S-wave K* mesons is crucial for understanding the production and decay of these axial vector mesons. The S-wave K* mesons play a significant role due to triangle singularity conditions and introduce special interference effects in the exclusive decays of the light axial vector mesons.