# Europhysics Conference on High-Energy Physics 2011

20-27 July 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

## The study of gamma/phi_3-sensitive hadronic decays at LHCb

21 Jul 2011, 12:30
15m
Oisans (Alpes Congrès - Alpexpo)

### Oisans

#### Alpes Congrès - Alpexpo

Parallel session talk Flavour Physics and Fundamental Symmetries

### Speaker

Mr Angelo Carbone

### Description

Temporary : merging of (abstracts 380,386,396) The relative abundances of the three decay modes B0 -> DK, B0 -> Dπ and Bs ->Dsπ produced in 7 TeV pp collisions at the LHC are determined from data corresponding to an integrated luminosity of ∼35 pb−1. The relative branching ratio of B0 -> DK with respect to B0 -> Dπ is found to be B(B0 ->DK) = (2.01 \pm 0.18 stat \pm 0.12 syst ) x 10−4 . The ratio of fragmentation fractions fs /fd is determined through the relative abundances of B0 -> DK and B0 -> Dπ with respect to Bs -> Dsπ, leading to fs /fd = 0.253 \pm 0.017 \pm 0.018 \pm 0.020, where the uncertainties are respectively statistical, systematic, and theoretical. Using a large data sample accumulated at a centre-of-mass energy √s = 7 TeV with the CERN LHCb experiment, we study the decays B± -> DK± where the neutral D meson decays into two track final states. These measurements are sensitive to the value of the CKM Unitarity Triangle angle gamma. Using data collected by the LHCb detector we reconstruct a sample of the main charmless charged two-body $B$ hadron decay modes, namely $B^0 \rightarrow \pi^+\pi^-$, $B^0 \rightarrow K^+\pi^-$, $B^0_s \rightarrow K^+K^-$, $B^0_s \rightarrow \pi^+K^-$, $\Lambda_b \rightarrow p K^-$ and $\Lambda_b \rightarrow p \pi^-$. We provide preliminary values of the direct $\mathcal{CP}$ asymmetries in the $B^0 \rightarrow K^+\pi^-$ and $B^0_s \rightarrow \pi^+K^-$ decays, of the relative branching fractions and of the $B^0_s \rightarrow K^+K^-$ lifetime. We also discuss the prospects for the measurement of time-dependent CP violation in the $B^0 \rightarrow \pi^+\pi^-$ and $B^0_s \rightarrow K^+K^-$ decays.

### Primary author

Dr Gaia Lafranchi (LNF INFN)

 Slides