ICHEP 2024

Measurements of CP violation in B decays at Belle II

20 Jul 2024, 17:45

15m

South Hall 1B

Parallel session talk 05. Quark and Lepton Flavour Physics Quark and Lepton Flavour Physics

Speaker

Dr Yu Nakazawa (KEK IPNS)

Description

The Belle$$II experiment has collected a 362 fb${}^{-1}$ sample of $e^{+}{e}^{-}\to B\overline{B}$ decays at the $\mathrm{{\rm Y}}(4S)$ resonance. The asymmetric-energy SuperKEKB collider provides a boost to the $B$ mesons in the laboratory frame, enabling measurements of time-dependent $CP$ violation. We present measurements of both time-dependent and direct $CP$ violation in hadronic $B$ decays. Among the new results, we measure $CP$-violating parameters related to the determination of the least well-known angle of the unitarity triangle, ${\varphi }_2$ (also known as $\alpha$), using the decays $B^0\to {\rho }^{+}{\rho }^{-}$ and $B^0\to {\pi }^0{\pi }^0$. In addition, the penguin-sensitive $B^0\to J/\psi {\pi }^0$ decay is studied; the results from this mode constrain the systematic effects related to the determination of the unitarity-triangle angle ${\varphi }_1$ (also known as $\beta$).

Presentation materials

20240720.yunakazawa.ichep2024.pdf