Measurement of Time-Dependent CP Asymmetry in $B^0\to D^{(*)\pm}\pi^\mp$ Decays and Constraints on $sin(2\beta+\gamma)$

TL;DR

This paper measures time-dependent CP asymmetries in B0 decays to D(*)±π∓, providing constraints on the CKM angle combination sin(2β+γ) and testing CP violation in the B meson system.

Contribution

First measurement of CP asymmetries in B0→D(*)±π∓ decays, constraining sin(2β+γ) and testing the Standard Model's CP violation predictions.

Findings

|sin(2β+γ)| > 0.69 at 68% CL

No CP violation hypothesis (sin(2β+γ)=0) excluded at 83% CL

Results consistent with Standard Model expectations

Abstract

We present a measurement of time-dependent CP-violating asymmetries in fully reconstructed $B^0->D^{(*)\pm}\pi^\mp$ decays in a data sample of approximately 88 million $Y(4S)\to B\bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC. We interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle, and find $|sin(2\beta+\gamma)|>0.69$ at 68% confidence level. We exclude the hypothesis of no CP-violation ($sin(2\beta+\gamma) = 0$) at 83% confidence level.