Measurement of Time-Dependent CP Asymmetries and Constraints on sin(2 beta+gamma) with Partial Reconstruction of B0->D*-+ pi+- Decays

TL;DR

This paper reports a preliminary measurement of CP asymmetry in B0 decays to D*-+ pi+- using partial reconstruction, providing insights into the parameters of the CKM matrix and CP violation.

Contribution

It introduces a partial reconstruction method to measure time-dependent CP asymmetries in B0 decays, offering a new approach to constrain sin(2β+γ).

Findings

Measured CP asymmetry amplitude: -0.041 ± 0.016 (stat) ± 0.010 (syst)

Set bounds on |sin(2β+γ)|

Utilized approximately 178 million BB events

Abstract

We present a preliminary measurement of the time-dependent CP-violating asymmetry in decays of neutral B mesons to the final states D*-+ pi+- using approximately 178 million BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the amplitude of the asymmetry to be $-0.041 \pm 0.016 (stat.) \pm 0.010 (syst.)$ and determine bounds on $|\sin(2 \beta + \gamma)|$.