$B \to K \ell^{+}\ell^{-}$ decay at large hadronic recoil

Understand

We predict the amplitude of the $B\to K \ell^+\ell^-$ decay in the region of the dilepton invariant mass squared $0<q^2\leq m_{J/\psi}^2$, that is, at large hadronic recoil.

• The $B\to K$ form factors entering the factorizable part of the decay amplitude are obtained from QCD light-cone sum rules.
• The nonlocal effects, generated by the four-quark and penguin operators combined with the electromagnetic interaction, are calculated at $q^2<0$, far below the hadronic thresholds.
• For hard-gluon contributions we employ the QCD factorization approach.