Determination of the CKM angle ${\varphi }_3$ from a combination of Belle and Belle II results

Abstract

We report a determination of the CKM angle ${\varphi }_3$, also known as $\gamma$, from a combination of measurements using samples of up to 711~fb${}^{-1}$ from the Belle experiment and up to 362~fb${}^{-1}$ from the Belle II experiment. We combine results from analyses of $B^{+}\to D{K}^{+},B^{+}\to D{\pi }^{+}$, and $B^{+}\to D^{\ast }{K}^{+}$ decays, where $D$ is an admixture of $D^0$ and $\overline{D}{}^0$ mesons, in a likelihood fit to obtain ${\varphi }_3=(78.6_{-7.3}^{+7.2}{)}^{\circ }$. We also briefly discuss the interpretation of this result.

31 pages, 4 figures