Theoretical overview on heavy flavor physics at LHCb

Precise prediction of the heavy hadrons decay amplitudes is of great importance in the determination of the parameters of KM matrix and searching for new physics signals beyond the standard model. Due to the high accuracy of the B meson decay constants, the structure dependent QED corrections should be taken into account for $B\to {\mu }^{+}{\mu }^{-}$ decays due to the power enhancement, but this effect is numerically negligible for $B\to {\tau }^{+}{\tau }^{-}$. The radiative leptonic decays and double radiative decays are the best channels to determine the B meson distribution amplitudes, but one should systematically deal with the power corrections to reduce the uncertainty. The heavy-to-light form factors is one of the most important nonperturbative quantities, and an improved method to improve the theoretical accuracy is to fit the form factors using combined data from Lattice and light-cone sum rules which works well at large recoil region. The power suppressed weak annihilation contribution is phenomenologically important in the nonleptonic decays, and the previously neglected hard-collinear gluon exchange diagrams have the potential to cancel the endpoint singularity arising from the hard gluon exchange. Therefore, more endeavors need to be paid to this topic.