K→πℓ+ℓ−form factor in the large-Ncand cutoff regularization method

Estefania Coluccio Leskow, Giancarlo D'Ambrosio, David Greynat, Atanu Nath
2016 Physical Review D  
Bardeen-Buras-Gérard have proposed a large N_c method to evaluate hadronic weak matrix elements to attack for instance the determination of the Δ I= 1/2-rule and Re(ϵ'/ϵ). Here we test this method to the determination of the form factor parameters a_+ and b_+ in the decays K^+ →π^+ ℓ^+ ℓ^- and K_S →π ^0 ℓ^+ ℓ^-. The results are encouraging: in particular after a complete treatment of Vector Meson Dominance (VMD).
doi:10.1103/physrevd.93.094031 fatcat:feaibgkio5gfdgqtr4zgqc3jsy