Twist-3 light-cone distribution amplitudes of the scalar mesons within the QCD sum rules and their application to the B →S transition form factors

We investigate the twist-3 light-cone distribution amplitudes (LCDAs) of the scalar mesons a0, K*0 and f0 within the QCD sum rules. The QCD sum rules are improved by a consistent treatment of the sizable s -quark mass effects within the framework of the background field approach. Adopting the valence quark component (anti q1 q2) as the dominant structure of the scalar mesons, our estimation for their masses is close to the measured a0(1450), K*0(1430) and f0(1710). From the sum rules, we obtain the first two non-zero moments of the twist-3 LCDAs φs,σa0: left angle ξs,a02(4) right angle =0.369(0.245) and left angle ξσ,a02(4) right angle =0.203 (0.093); those of the twist-3 LCDAs φK*0s,σ: left angle ξs,K*01(2) right angle =0.004(0.355) and left angle ξσ,K*01(2) right angle =0.018(0.207); and those of the twist-3 LCDAs φf0s,σ: left angle ξs,f02(4) right angle =0.335(0.212) and left angle ξσ,f02(4) right angle =0.196(0.088), respectively. As an application of those twist-3 LCDAs, we study the B→S transition form factors by introducing proper chiral currents into the correlator, which is constructed such that the twist-3 LCDAs give dominant contribution and the twist-2 LCDAs make negligible contribution. Our results of the B→S transition form factors at the large recoil region q2≅0 are consistent with those obtained in the literature, which inversely shows the present twist-3 LCDAs are acceptable. (orig.)