We report observations of CP violation in the decays B-0 -> K+pi(-) and B-0 ->pi(+)pi(-) in a sample of 383 x 10(6) Upsilon(4S)-> B (B) over bar events. We find 4372 +/- 82 B-0 -> K+pi(-) decays and measure the direct CP-violating charge asymmetry A(K pi)=-0.107 +/- 0.018(stat)(-0.004)(+0.007)(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample, we find 1139 +/- 49 B-0 ->pi(+)pi(-) decays and measure the CP-violating asymmetries S-pi pi=-0.60+/-0.11(stat) +/- 0.03(syst) and C-pi pi=-0.21 +/- 0.09(stat) +/- 0.02(syst). CP conservation in B-0 ->pi(+)pi(-) (S-pi pi=C-pi pi=0) is excluded at a confidence level 1-C.L.=8 x 10(-8), corresponding to 5.4 standard deviations.
Observation of CP violation in B-0 -> K+pi(-) and B-0 ->pi(+)pi(-)
ANDREOTTI, Mirco;CALABRESE, Roberto;CECCHI, ANNALISA;CIBINETTO, Gianluigi;FRANCHINI, Paolo;LUPPI, Eleonora;NEGRINI, Matteo;PETRELLA, Antonio;PRENCIPE, Elisabetta;SANTORO, Valentina;
2007
Abstract
We report observations of CP violation in the decays B-0 -> K+pi(-) and B-0 ->pi(+)pi(-) in a sample of 383 x 10(6) Upsilon(4S)-> B (B) over bar events. We find 4372 +/- 82 B-0 -> K+pi(-) decays and measure the direct CP-violating charge asymmetry A(K pi)=-0.107 +/- 0.018(stat)(-0.004)(+0.007)(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample, we find 1139 +/- 49 B-0 ->pi(+)pi(-) decays and measure the CP-violating asymmetries S-pi pi=-0.60+/-0.11(stat) +/- 0.03(syst) and C-pi pi=-0.21 +/- 0.09(stat) +/- 0.02(syst). CP conservation in B-0 ->pi(+)pi(-) (S-pi pi=C-pi pi=0) is excluded at a confidence level 1-C.L.=8 x 10(-8), corresponding to 5.4 standard deviations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.