Measurements of CP-Violating Asymmetries in B0 to a1(1260)^{+-} pi^{-+} Decays

TL;DR

This paper reports measurements of CP-violating asymmetries in B0 decays to a_1(1260) pi, providing insights into CP violation and the CKM angle alpha using data from the BaBar experiment.

Contribution

First measurement of CP asymmetries in B0 to a_1(1260) pi decays, extracting the effective CKM angle alpha with data from 384 million B meson pairs.

Findings

Measured CP asymmetry A^{a_1 }_{CP}=-0.07+-0.07+-0.02

Determined the effective angle _{ m eff}=78.6^{\u00b0} b1 7.3b0

Provided values for mixing-induced and direct CP violation parameters

Abstract

We present measurements of CP-violating asymmetries in the decay B0 -> a_1(1260)^{+-} pi^{-+} with a_1(1260)^{+-} -> pi^{-+} pi^{+-} pi^{+-}. The data sample corresponds to 384 million B B-bar pairs collected with the BaBar detector at the PEP-II asymmetric B-factory at SLAC. We measure the CP-violating asymmetry A^{a_1 \pi}_{CP}=-0.07+-0.07+-0.02, the mixing-induced CP violation parameter S_{a_1 \pi}= 0.37 +-0.21+-0.07, the direct CP violation parameter C_{a_1 \pi}=-0.10+-0.15+-0.09, and the parameters \Delta C_{a_1 \pi}=0.26+-0.15+-0.07 and \Delta S_{a_1\pi}=-0.14+-0.21+-0.06. From these measured quantities we determine the angle \alpha_{\rm eff}= 78.6^{\circ} +- 7.3^{\circ}.