Study of CP-violating asymmetries in B(0)->pi( )pi(-) decays
K Abe, K Abe, T Abe, I Adachi, BS Ahn, H Aihara, M Akatsu, Y Asano, T Aso, V Aulchenko, T Aushev, AM Bakich, Y Ban, E Banas, I Bedny, S Behari, PK Behera, A Bondar, A Bozek, M Bracko Show all
Physical Review Letters | AMER PHYSICAL SOC | Published : 2002
We present a measurement of CP-violating asymmetries in B0-->pi(+)pi(-) decays based on a 41.8 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We fully reconstruct one neutral B meson as a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we obtain the CP-violating asymmetry parameters S(pipi)=-1.21(+0.38)(-0.27)(stat)+0.16-0.13(syst) and A(pipi)=+0.94(+0.25)(-0.31)(stat)+/-0.09(syst).