# Europhysics Conference on High-Energy Physics 2011

Jul 20 – 27, 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

## phi2 and phi3 measurements at Belle

Jul 21, 2011, 11:30 AM
15m
Oisans (Alpes Congrès - Alpexpo)

### Oisans

#### Alpes Congrès - Alpexpo

Parallel session talk Flavour Physics and Fundamental Symmetries

### Speaker

Dr Jeremy Dalseno (MPI, Munich)

### Description

We present a time-dependent measurement of CP violation parameters in $B^0 \to \pi^+\pi^-$ decays. We present also a measurement of the branching fraction of $B^0 \to \rho^0 \rho^0$ decays, which could provide a tighter constraint of the CKM angle $\phi_2$. In addition we present measurements of branching ratios of other charmless $B$ decays into 4 charged pions. We present a measurement of the branching fraction and time-dependent CP violation parameters of $B^0 \to a_1^{\pm}\pi^{\mp}$ decays. The measurement of $B\to\pi^0\pi^0$ is vital in the extraction of the UT angle $\phi_2$, from an isospin analysis of the $B\to\pi\pi$ system. In addition, this process is expected to exhibit direct CP violation, a measurement of which would place additional constraints on $\phi_{2}$, and a new measurement of $B\rightarrow\pi^0\pi^0$ would help resolve the significant disagreement in the Belle and BaBar measurements of this mode. The decay $B^- \to D^{(*)} K^-$ ($D = D^0$ or $\bar{D}^0$) includes the $b \to u$ transition and plays a crucial role in the measurement of the CP-violating angle $\phi_3$. We present the results of a study of the decay $B \to D^{(*)} K^-$ where the $D$ meson is reconstructed from $K^+ \pi^-$ and from $CP$ modes. We report the first measurement of the angle $\phi_{3}$ of the unitarity triangle using a binned model-independent Dalitz plot analysis technique of $B^{\pm} \rightarrow DK^{\pm}$, $D \rightarrow K^{0}_{S}\pi^{+}\pi^{║щ}$ decay chain. These results are obtained from the final data sample that contains 772 million $B\overline{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.

### Primary author

Dr Jeremy Dalseno (MPI, Munich)

 Slides