  We present a preliminary measurement of \rone, \rtwo and \rhosq which are the
three parameters used to characterize the $B\rar D^*\ell\bar\nu_e$ form factors
($A_1$, $V$, and $A_2$). We use $85 \times 10^6$ $B\bar B$-pairs accumulated on
the \upsfs resonance at PEP-II. In this analysis we use the decay mode $\bar
B^0\rar D^{+*}e^-\bar\nu$ and its charge conjugate. The $D^{*+}$ is
reconstructed in the channel $D^{*+}\to D^0\pi^+$ and the $D^0$ in the channel
$\dtokpi$. We parameterize the \ff s in terms of their ratios (determined by
the parameters $R_1$ and $R_2$) and the common slope $\rhosq$ in the variable
$w$ (a quantity related to the momentum transfer in the decay process). These
parameters are determined via an unbinned maximum likelihood fit to the
distributions in four kinematic variables (three decay angles and $w$). The
results are $R_1= 1.328 \pm 0.055\pm 0.025\pm 0.025$ and $R_2=0.920 \pm
0.044\pm 0.020\pm 0.013 $ for the ratios and $\rhosq= 0.769\pm 0.039 \pm
0.019\pm 0.032 $ for the slope. The stated errors are the statistical
uncertainty from the data, statistical uncertainty from the size of the Monte
Carlo sample and the systematic uncertainty, respectively.

High Energy Physics - Experiment