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

TL;DR

This paper measures time-dependent CP asymmetries in B0 decays to D*-+ pi+- using partial reconstruction, providing constraints on the combination of CKM angles 2beta+gamma, with results based on 82 million B B bar events.

Contribution

It introduces a partial reconstruction method to measure CP asymmetries in B0 decays, offering new constraints on CKM parameters.

Findings

Measured CP asymmetry amplitude: -0.063 ± 0.024 (stat) ± 0.014 (syst)

Provided bounds on |sin(2beta+gamma)|

Used approximately 82 million B B bar events

Abstract

We present a measurement of time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*-+ pi+-, using approximately 82 million B B bar 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 -0.063 +- 0.024(stat.) +- 0.014(syst.) and compute bounds on |sin(2beta + gamma)|.