Search For $T$, $CP$, and $CPT$ Violation in $B^0\mathrm{\text{−}}{\overline{B}}^0$ Mixing with Inclusive Dilepton Events

We report the results of a search for $T$, $CP$, and $CPT$ violation in $B^0\mathrm{\text{−}}{\overline{B}}^0$ mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II $B$ factory. Using a sample of $232\times {10}^6$ $B\overline{B}$ pairs, we measure the $T$ and $CP$ violation parameter $|q/p|-1=\mathbf{(}-0.8\pm 2.7(\mathrm{stat})\pm 1.9(\mathrm{syst})\mathbf{)}\times {10}^{-3}$, and the $CPT$ and $CP$ parameters $\mathrm{Im}z=\mathbf{(}-13.9\pm 7.3(\mathrm{stat})\pm 3.2(\mathrm{syst})\mathbf{)}\times {10}^{-3}$ and $\Delta \Gamma \times \mathrm{Re}z=\mathbf{(}-7.1\pm 3.9(\mathrm{stat})\pm 2.0(\mathrm{syst})\mathbf{)}\times {10}^{-3}{\mathrm{ps}}^{-1}$. The statistical correlation between the measurements of $\mathrm{Im}z$ and $\Delta \Gamma \times \mathrm{Re}z$ is 76%.

Figure 1

(a) $A_{T/CP}$ asymmetry between ($l^{+},l^{+}$) and ($l^{-},l^{-}$). A larger charge asymmetry for cascade muons, dominant at small $|\Delta t|$, explains the nonflatness of the curve. (b) $A_{CPT/CP}$ asymmetry between $(l^{+},l^{-})$ dileptons with $\Delta t>0$ and $\Delta t<0$.