Scalar form-factors fππ(Q2) and fKK(Q2) with light-cone QCD sum rules

Abstract

In this paper, we calculate the scalar form-factors fππ(Q2) and fKK(Q2) in the framework of the light-cone QCD sum rules approach. The numerical value of fππ(Q2) changes quickly with the variation of Q2 near zero momentum transfer, while fKK(Q2) has a rather good behavior at small momentum transfer. The value fKK(0) = 2.21+0.35−0.19 GeV is compatible with the result from the leading order chiral perturbation theory. At large momentum transfer with Q2 > 6 GeV2, the form-factor fππ(Q2) takes up the asymptotic behavior approximately, while fKK(Q2) decreases more quickly than .