Regarding the axial-vector mesons

The implications of the f1(1285)-f1(1420) mixing for the K1(3P1)-K1(1P1) mixing angle are investigated. Based on the f1(1285)-f1(1420) mixing angle ∝50 suggested from the analysis for a substantial body of data concerning the f1(1420) and f1(1285), the masses of the K1(3P1) and K1(1P1) are determined to be ∝1307.35±0.63 MeV and 1370.03±9.69 MeV, respectively, which therefore suggests that the K1(3P1)-K1(1P1) mixing angle is about ±(59.55±2.81) . Also, it is found that the mass of the h'1(1P1) (mostly of s) state is about 1495.18±8.82 MeV. Comparison of the predicted results and the available experimental information of the h1(1380) shows that without further confirmation on the h1(1380), the assignment of the h1(1380) as the s member of the 1P1 meson nonet may be premature. (orig.)