Matching Chiral Perturbation Theory and the Dispersive Representation of the Scalar Kpi Form Factor

Understand

We perform a matching of the two loop-chiral perturbation theory representation of the scalar Kpi form factor to a dispersive one.

• Knowing the value of F_K/F_pi and f_+(0) in the Standard Model (SM) allows to determine two O(p^6) LECs, the slope of the scalar form factor and the deviation of the Callan-Treiman theorem.
• Going beyond the SM and assuming the knowledge of the slope of the scalar form factor from experiment, the matching allows us to determine the ratio of F_K/F_pi, f_+(0), a certain combination of non-standard couplings, the deviation of the Callan-Treiman theorem and the two O(p^6) LECs.