Search for the decay $B^0\to DK^{*0}$ followed by $D\to K^-\pi^+$

TL;DR

This study investigates the decay process of B^0 mesons into D and K^*0 states, measuring the decay rate ratio to explore CP violation effects, using a large dataset collected at the Belle experiment.

Contribution

First measurement of the decay rate ratio for B^0 to D K^*0 with D decaying to K pi, providing constraints on CP violation parameters in B meson decays.

Findings

Measured decay rate ratio ${ m R}_{DK^{*0}}$ as approximately 4.1% with large uncertainties.

Set an upper limit of 16% on the decay rate ratio at 95% confidence level.

Contributed to understanding of CP violation in B meson decays.

Abstract

We report a study of the decay $B^0\rightarrow D K^+\pi^-$ followed by $D\rightarrow K^-\pi^+$, where $D$ indicates $D^0$ or $\bar{D}^0$. We reconstruct the $D K^+\pi^-$ state in a phase space corresponding to $D K^{*}(892)^0$. The CP-violating angle $\phi_3$ affects its decay rate via the interference between $b\rightarrow u$ and $b\rightarrow c$ transitions. The result is obtained from a 711 ${\rm fb}^{-1}$ data sample that contains 772 $\times 10^6 B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure the ratio ${\cal R}_{DK^{*0}} \equiv \Gamma(B^0\rightarrow [K^-\pi^+]_DK^+\pi^-)/\Gamma(B^0\rightarrow [K^+\pi^-]_DK^+\pi^-)$ to be $(4.1 ^{+ 5.6 + 2.8}_{- 5.0 - 1.8}) \times 10^{-2}$, and set an upper limit of ${\cal R}_{DK^{*0}} < 0.16$ at the 95% confidence level.