Two loop virtual corrections to $b\to(d,s)\ell^+\ell^-$ and $c\to u\ell^+\ell^-$ for arbitrary momentum transfer

Abstract

Non-factorizable two loop corrections to heavy to light flavor changing neutral current transitions due to matrix elements of current-current operators are calculated analytically for arbitrary momentum transfer. This extends previous works on $b\to(d,s)\ell^+\ell^-$ transitions. New results for $c\to u\ell^+\ell^-$ transitions are presented. Recent works on polylogarithms are used for the master integrals. For $b\to s\ell^+\ell^-$ transitions, the corrections are most significant for the imaginary parts of the effective Wilson coefficients in the large hadronic recoil range. Analytical results and ready-to-use fitted results for a specific set of parameters are provided.