2022 Impact factor 4.4
Particles and Fields
Eur. Phys. J. C 14, 271-274
DOI 10.1007/s100520000350

Model independent calculation
of ${\cal{B}}({\bar{B}}^0\rightarrow D^{(*)+} \tau^- {\bar{\nu}})/
{\cal{B}}({\bar{B}}^0\rightarrow D^{(*)+} e^- {\bar{\nu}})$

D.S. Hwang1 - D.-W. Kim2

1 Department of Physics, Sejong University, Seoul 143-747, Korea
2 Department of Physics, Kangnung National University, Kangnung 210-702, Korea

Received: 20 September 1999 / Revised version: 30 November 1999 /
Published online: 6 April 2000 - © Springer-Verlag 2000

Using the formulas for the ${\mathrm {d}}\Gamma / {\mathrm {d}}q^2$distribution with non-zero lepton mass and experimentally determined form factors, we calculate the ${\mathrm {d}}\Gamma (D^{(*)+} l^- {\bar{\nu}})/
{\mathrm {d}}q^2$spectra and branching fractions for l=e, $\mu$ and $\tau$. We obtain the results ${\cal{B}}({\bar{B}}^0\rightarrow D^{+} \tau^- {\bar{\nu}})/
{\cal{B}}({\bar{B}}^0\rightarrow D^{+} e^- {\bar{\nu}})=

${\cal{B}}({\bar{B}}^0\rightarrow D^{*+} \tau^- {\bar{\nu}})/
{\cal{B}}({\bar{B}}^0\rightarrow D^{*+} e^- {\bar{\nu}})=
0.256^{+0.014}_{-0.013}$ . Since we used the experimentally measured form factors, these results are independent of theoretical models of the form factors.

Copyright Società Italiana di Fisica, Springer-Verlag 2000