Regarding the axial-vector mesons

The implications of the $f_1(1285)-f_1(1420)$ mixing for the $K_1{(}^3{P}_1)-K_1{(}^1{P}_1)$ mixing angle is investigated. Based on the $f_1(1285)-f_1(1420)$ mixing angle $\sim {50}^{\circ }$ suggested from the analysis for a substantial body of data concerning the $f_1(1420)$ and $f_1(1285)$, the masses of the $K_1{(}^3{P}_1)$ and $K_1{(}^1{P}_1)$ are determined to be $\sim 1307.35\pm 0.63$MeVand$1370.03\pm 9.69$ MeV, respectively, which therefore suggests that the $K_1{(}^3{P}_1)-K_1{(}^1{P}_1)$ mixing angle is about $\pm (59.55\pm 2.81)^\circ$\mathrm{.}Also,itisfoundthatthemassofthe$h^\prime_1(^1P_1)$(mostlyof$s\bar{s}$)stateisabout$1495.18\pm 8.82$ MeV. Comparison of the predicted results and the available experimental information of the $h_1(1380)$ shows that without further confirmation on the $h_1(1380)$, the assignment of the $h_1(1380)$ as the $s\bar{s}$ member of the ${}^1{P}_1$ meson nonet may be premature.