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We present our recent results for long-distance QCD effects in the FCNCradiative leptonic decays $B\to\gamma\ell^+\ell^-$, $\ell=\{e,\mu\}$. Oneencounters here two distinct types of long-distance effects: those encoded inthe $B\to\gamma$ transition form factors induced by the $b\to q$ quarkcurrents, and those related to the charm-loop effects. We calculate the$B\to\gamma$ form factors in a broad range of the momentum transfers making useof the relativisitc dispersion approach based on the constituent quark picturewhich has proven to provide reliable predictions for many weak-transition formfactors. Concerning the description of the charm-loop contributions, we pointout two observations: First, the precise description of the charmoniumresonances, in particular, the relative phases between $\psi$ and $\psi'$, hasimpact on the differential distributions and on the forward-backward asymmetry,$A_{\rm FB}$, in a broad range of $q^2\ge 5$ GeV$^2$. Second, the shape of$A_{\rm FB}$ in $B\to\gamma\ell^+\ell^-$ and in $B\to V\ell^+\ell^-$ ($V$ thevector meson) {\it in the $q^2$-region between $\psi$ and $\psi'$} provides anunambiguous probe of the relative phases between $\psi$ and $\psi'$. Fixing thelatter will lead to a strong reduction of the theoretical uncertainties in$A_{\rm FB}$ at $q^2=5-9$ GeV$^2$ where it has the sensitivity to physicsbeyond the SM.

Rare FCNC radiative leptonic decays $B\to\gamma\ell^+\ell^-$