Study of the K1(1270) - K1(1400) mixing in the decays B → J/ψ K1(1270), J/ψ K1(1400)

We study the B meson decays B -> J/psi K-1 (1270, 1400) in the pQCD approach beyond the leading order. With the vertex corrections and the NLOWilson coefficients included, the branching ratios of the considered decays are predicted as Br(B+ -> J/psi K-1(1270)(+)) = 1.76(-0.69)(+0.65)x 10(-3), Br(B+ -> J/psi K-1(1400)(+)) = 6.47(-2.34)(+2.50) x 10(-4), and Br(B-0 -> J/psi K-1(1270)(0)) = (1.63(-0.64)(+0.60)) x10(-3) with the mixing angle theta K-1 = 33 degrees, which can agree well with the data or the present experimental upper limit within errors. So we support the opinion that theta K-1 similar to 33 degrees is much more favored than 58 degrees. Furthermore, we also give the predictions of the polarization fractions, the direct CP violations, the relative phase angles for the considered decays with the mixing angle theta K-1 = 33 degrees and 58 degrees, respectively. The direct CP violations of the two charged decays B+ -> J/psi K-1(1270, 1400)(+) are very small (10(-4) similar to 10(-5)), because the weak phase is very tiny. In order to check the dependence of the results on the nonperturbative input parameters, we also calculate them by using the harmonic-oscillator type wave functions for the J/psi meson. These results can be tested at the running LHCb and forthcoming Super-B experiments.