Analysis of the vector form factors f+ Kπ(Q2) and f- Kπ(Q2) with light-cone QCD sum rules

Abstract

In this article, we calculate the vector form factors f+ Kπ(Q2) and f- Kπ(Q2) within the framework of the light-cone QCD sum rule approach. The numerical values of f+ Kπ(Q2) are compatible with existing theoretical calculations, and the central value of f+ Kπ(0) (f+ Kπ(0)=0.97) is in excellent agreement with the values from chiral perturbation theory and lattice QCD. The values of |f- Kπ(0)| are very large compared to the theoretical calculations and experimental data, and they cannot give any reliable prediction. At large momentum transfer with Q2 > 5 GeV2, the form factors f+ Kπ(Q2) and |f- Kπ(Q2)| can either show the asymptotic behavior of \(\frac{1}{Q^2}\) or decrease more quickly than \(\frac{1}{Q^2}\); more experimental data are needed to select the ideal sum rules.