Test of $CPT$ Symmetry in $CP$-violating $B$ Decays

Considering that the existing experimental limit for $CPT$ violation is still poor, we explore various possible ways to test $CPT$ symmetry in $CP$-violating $B$ decays at $e^{+}e^{-}$ $B$ factories. We find that it is difficult to distinguish between the effect of direct $CP$ violation and that of $CPT$ violation in the time-integrated measurements of neutral $B$ decays to $CP$ eigenstates such as $\psi K_{S}$ and $\pi^{+}\pi^{-}$. Instead, a cleaner signal of small $CPT$ violation may appear in the time-integrated $CP$ asymmetries for a few non-$CP$-eigenstate channels, e.g., $B^{0}_{d}/\bar{B}^{0}_{d}\rightarrow D^{\pm}\pi^{\mp}$ and $\stackrel{(-)}{D}$$^{(*)0}K_{S}$. The time-dependent measurements of $CP$ asymmetries are available, in principle, to limit the size of $CPT$-violating effects in neutral $B$-meson decays.