Improved measurements of CP-violating asymmetry amplitudes in B0-->pi+pi- decays

Phys Rev Lett. 2005 Oct 7;95(15):151803. doi: 10.1103/PhysRevLett.95.151803. Epub 2005 Oct 4.

Abstract

We present updated measurements of the CP-violating parameters Spipi and Cpipi in B0-->pi+pi- decays. Using a sample of 227x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC, we observe 467+/-33 signal decays and measure Spipi=-0.30+/-0.17(stat)+/-0.03(syst) and Cpipi=-0.09+/-0.15(stat)+/-0.04(syst).