; Fang, Zhen-Yun] Chongqing Univ, Dept Phys, Chongqing 400044, Peoples R China
; [Huang, Tao] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
We present an improved calculation of the B -> K transition form factor with a chiral current in the QCD light-cone sum rule approach. Under the present approach, the most uncertain twist-3 contribution is eliminated. And the contributions from the twist-2 and the twist-4 structures of the kaon wave function are discussed, including the SU(f)(3)-breaking effects. One-loop radiative corrections to the kaonic twist-2 contribution together with the leading-order twist-4 corrections are studied. The SU(f)(3)-breaking effect is obtained, F(+)(B -> K)(0)/F(+)(B ->pi)(0)=1.16 +/- 0.03. By combining the light-cone sum rule results with the newly obtained perturbative QCD results that have been calculated up to O(1/m(b)(2)) by Wu, Huang, and Fang [Eur. Phys. J. C 52, 561 (2007)], we present a consistent analysis of the B -> K transition form factor in the large and intermediate energy regions.