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

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 do not make any contribution and therefore the possible pollution by them can be avoided, to reexamine $\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\pi}$ semileptonic form factors. Also, a comparison between previous results and our results from the light-cone QCD sum rules is made. Our method will be beneficial to the precise extraction of $|{V}_{\mathrm{ub}}|$ from the experimental data on the processes $\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\pi}l{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\nu}}}_{l}.$