Phenomenology of axial-vector and pseudovector mesons: decays and mixing in the kaonic sector

TL;DR

This paper analyzes the decays and mixing of axial-vector and pseudovector mesons, especially in the kaonic sector, providing a good description of decay patterns and precise mixing angle predictions that can test beyond Standard Model theories.

Contribution

It offers a quarkonium-based model for meson decays and mixing, with new precise determination of the $K_1$ mixing angle in the kaonic sector.

Findings

Good description of meson decay patterns

Determined $K_1$ mixing angle as approximately 33.6 degrees

Results consistent with previous studies but with reduced uncertainty

Abstract

We study the decays of the lightest axial-vector and pseudovector mesons, interpreted as quark-antiquark states, into a vector and a pseudoscalar meson. We show that the quarkonium assignment delivers a good description of the decays and allows also to make further testable predictions. In the kaonic sector, the physical resonances $K_{1}(1270)$ and $K_{1}(1400)$ emerge as mixed objects of an axial vector state $K_{1,A}$ and a pseudovector state $K_{1,B}$. We determine the mixing angle as $\left\vert \theta_{K}\right\vert=\left(33.6\pm4.3\right) ^{\circ}$, a value compatible with previous studies but with a smaller uncertainty. This result may be helpful for testing models beyond the Standard Model of particle physics in which decays into the kaonic resonances $K_{1}(1270)$ and $K_{1}(1400)$ are investigated.