Improved approach to the heavy-to-light form factors in the light-cone QCD sum

A systematic analysis shows that the main uncertainties in the form factors are due to the twist-3 wave functions of the light mesons in the light-cone QCD sum rules. We propose an improved approach, in which the twist-3 wave functions doesn't make any contribution and therefore the possible pollution by them can be avoided, to re-examine $B \to \pi$ semileptonic form factors. Also, a comparison between the previous and our results from the light-cone QCD sum rules is made. Our method will be beneficial to the precise extracting of $\mid{V_{ub}}\mid$ from the experimental data on the processes $B \to \pi \ell \widetilde{\nu_\ell}$.