Measurement of the CKM angle $\varphi_1$ in $B^0\to\bar{D}{}^{(*)0}h^0$, $\bar{D}{}^0\to K_S^0\pi^+\pi^-$ decays with time-dependent binned Dalitz plot analysis

Abstract

We report a measurement of the CP violation parameter $\varphi_1$ obtained in a time-dependent analysis of $B^0\to\bar{D}{}^{(*)0}h^0$ decays followed by $\bar{D}{}^0\to K_S^0\pi^+\pi^-$ decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is $\varphi_1 = 11.7^{\circ}\pm7.8^{\circ}({\rm stat.})\pm 2.1^{\circ}({\rm syst.})$. Treating $\sin{2\varphi_1}$ and $\cos{2\varphi_1}$ as independent parameters, we obtain $\sin{2\varphi_1} = 0.43\pm 0.27({\rm stat.})\pm 0.08({\rm syst.})$ and $\cos{2\varphi_1} = 1.06\pm 0.33({\rm stat.})^{+0.21}_{-0.15}({\rm syst.})$. The results are obtained with a full data sample of $772 \times 10^6 B\bar{B}$ pairs collected near the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.