K1(1270)-K1(1400) mixing and the fourth generation standard model effects in B→K1l+l- decays

The implications of the fourth-generation quarks in the B→K1(1270,1400)l+l- with l=μ, τ decays are studied, where the mass eigenstates K1(1270) and K1(1400) are the mixture of 1P1 and 3P1 states with the mixing angle θK. In this context, we have studied various observables like branching ratio (BR), forward-backward asymmetry (AFB) and longitudinal and transverse helicity fractions (fL,T) of K1 meson in B→K1l+l- decays. To study these observables, we have used the light-cone QCD sum rules form factors and set the mixing angle θK=-34 deg. It is noticed that the BR is suppressed for K1(1400) as a final state meson compared to that of K1(1270). Same is the case when the final state leptons are tauons rather than muons. In both the situations, all the above mentioned observables are quite sensitive to the fourth-generation effects. Hence the measurements of these observables at LHC, for the above mentioned processes can serve as a good tool to investigate the indirect searches for the existence of fourth-generation quarks.