On the problem of isodoublet of 1 3 P 1 meson state

In the framework of meson–meson mass mixing, we investigate the mass of isodoublet of the 1 3 P 1 meson nonet in the presence of a 1 (1260), f 1 (1285) and f 1 (1420) being the 1 3 P 1 meson state and the decays of the states f 1 (1285) and f 1 (1420). The results are in agreement with the values predicted by other theoretical approaches and the experimental data. As a byproduct, with the help of the mass of isodoublet of the 1 3 P 1 meson nonet, we obtain the mixing angle between the K 1 (1270) and K 1 (1400) mesons. Our results should be tested in the experiment in the future.