Model Independent Calculation of $\mathcal{B}({\bar{B}}^0\to D^{(\ast )+}{\tau }^{-}\bar{\nu })\mathrm{/}\mathcal{B}({\bar{B}}^0\to D^{(\ast )+}{e}^{-}\bar{\nu })$

Using the formulas for the $d\mathrm{\Gamma }\mathrm{/}d{q}^2$ distribution with non-zero lepton mass and experimentally determined form factors, we calculate the $d\Gamma (D^{()+} l^- {\bar{\nu}})/ dq^2$spectraandbranchingfractionsfor$l=e$,$\mu$and$\tau$\mathrm{.}Weobtaintheresults${\cal{B}}({\bar{B}}^0\rightarrow D^{+} \tau^- {\bar{\nu}})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{+} e^- {\bar{\nu}})= 0.278^{+0.049}_{-0.035}$and${\cal{B}}({\bar{B}}^0\rightarrow D^{+} \tau^- {\bar{\nu}})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{*+} e^- {\bar{\nu}})= 0.256^{+0.014}_{-0.013}$ . Since we used the experimentally measured form factors, these results are independent of theoretical models of form factors.