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

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 $\left|{\theta }_K\right|={\left(33.6\pm 4.3\right)}^{\circ }$, 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.

Comments: 14 pages, 4 tables; to appear in EPJA