Recent results on $\phi_3$ at Belle

TL;DR

This paper reports improved measurements of the unitarity triangle angle φ₃ using Dalitz plot analysis of B⁺ decays and explores related B⁰ decay processes, providing more precise constraints on CP violation parameters.

Contribution

The study introduces a more accurate Dalitz plot analysis for φ₃ measurement and reports new branching fractions for specific B⁰ decay modes, enhancing understanding of CP violation.

Findings

φ₃ measured as 78.4° with uncertainties

Branching fraction for B⁰ → D_s^{*+} π⁻ is (1.75 ± 0.34 ± 0.17 ± 0.11)×10⁻⁵

Branching fraction for B⁰ → D_s^{*-} K⁺ is (2.02 ± 0.33 ± 0.18 ± 0.13)×10⁻⁵

Abstract

We report results of measurement of the unitarity triangle angle $\phi_3$ with $B^+\rightarrow D^{(*)}K^+$ Dalitz plot analysis and related issues with $B^0 \rightarrow D_s^{*+} \pi^-$ and $B^0 \rightarrow D_s^{*-} K^+$ decay processes. The Dalitz analysis improves accuracy of the angle $\phi_3$ as $78.4^\circ ~^{+10.8^\circ}_{-11.6^\circ}\pm 3.6^\circ\pm 8.9^\circ$ and the branching fractions are found to be $B^0 \rightarrow D_s^{*+} \pi^-(K^-)$ decays are set as $\mathcal{B}(B^0 \rightarrow D_s^{*+} \pi^-) = (1.75 \pm 0.34 (\mathrm{stat}) \pm 0.17(\mathrm{syst}) \pm 0.11(\mathcal{B})) \times 10^{-5}$ and $\mathcal{B}(B^0 \rightarrow D_s^{*-} K^+) = (2.02 \pm 0.33 (\mathrm{stat}) \pm 0.18({\rm syst}) \pm 0.13(\mathcal{B})) \times 10^{-5}$.