| Abstract |
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We present new measurements of time-dependent $C\!P$ asymmetries for
$B^0 \rightarrow D^{(*)+}D^{(*)-}$ decays using $(467 \pm 5)\times 10^6$ $B{\kern
0.18em\overline{\kern -0.18em B}{}}$ pairs collected with the \mbox{\slshape
B\kern-0.1em{\smaller A}\kern-0.1em B\kern-0.1em{\smaller A\kern-0.2em R}}
detector located at the PEP-II $B$ Factory at the Stanford Linear Accelerator
Center. We determine the $C\!P$-odd fraction of the $B^0 \rightarrow
D^{*+}D^{*-}$ decays to be $R_\perp = 0.158 \pm 0.028 \pm 0.006$ and find $C\!P$
asymmetry parameters for the $C\!P$-even component of the decay $S_+ = -0.76 \pm
0.16 \pm 0.04$ and $C_+ = 0.00 \pm 0.12 \pm 0.02$. We measure $S = -0.63 \pm 0.36
\pm 0.05$ and $C = -0.07 \pm 0.23 \pm 0.03$ for $B^0 \rightarrow D^+D^-$, $S =
-0.62 \pm 0.21 \pm 0.03$ and $C = 0.08 \pm 0.17 \pm 0.04$ for $B^0 \rightarrow
D^{*+}D^-$, and $S = -0.73 \pm 0.23 \pm 0.05$ and $C = 0.00 \pm 0.17 \pm 0.03$ for
$B^0 \rightarrow D^+D^{*-}$. For the $B^0 \rightarrow D^{*\pm}D^{\mp}$ decays, we
also determine the $C\!P$-violating asymmetry $\mathcal{A} = 0.008 \pm 0.048 \pm
0.013$. In each case, the first uncertainty is statistical and the second is
systematic. The measured values for the asymmetries are all consistent with the
Standard Model.
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