CP-violating Asymmetries In B0 Research Articles

Measurement ofCPasymmetries inB0→KS0KS0KS0decays

We present measurements of the time-dependent CP-violating asymmetries in B0 --> K0S K0S K0S decays based on 384 million Y(4S) decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We obtain the CP asymmetry parameters C = 0.02 +/- 0.21 +/- 0.05 and S = -0.71 +/- 0.24 +/- 0.04, where the first uncertainties are statistical and the second systematic. These results are consistent with standard model expectations.

Measurement ofCP-violating asymmetries inB0→(ρπ)0using a time-dependent Dalitz plot analysis

We report a measurement of CP-violating asymmetries in B0-->(rhopi)0-->pi+pi-pi0 decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 375 million Y(4S) --> BBbar decays, collected by the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure 26 coefficients of the bilinear form-factor terms occurring in the time-dependent decay rate of the B0 meson. We derive the physically relevant quantities from these coefficients. In particular, we measure a constraint on the angle alpha of the Unitarity Triangle.

Observation ofB+→K¯0K+andB0→K0K¯0

We report observations of the b --> d penguin-dominated decays B+ --> K0bar K+ and B0 --> K0 K0bar in approximately 350 million Upsilon(4S) --> BBbar decays collected with the BaBar detector. We measure the branching fractions B(B+ --> K0bar K+) = (1.61 +/- 0.44 +/- 0.09) * 10^-6 and B(B0 --> K0 K0bar) = (1.08 +/- 0.28 +/- 0.11) * 10^-6, and the CP-violating charge asymmetry A_{CP}(K0bar K+) = 0.10 +/- 0.26 +/- 0.03. Using a vertexing technique previously employed in several analyses of all-neutral final states containing kaons, we report the first measurement of time-dependent CP-violating asymmetries in B0 --> K0 K0bar, obtaining S = -1.28 +0.80/-0.73 +0.11/-0.16 and C = -0.40 +/- 0.41 +/- 0.06. We also report improved measurements of the branching fraction B(B+ --> K0 pi+) = (23.9 +/- 1.1 +/- 1.0) * 10^-6 and CP-violating charge asymmetry A_{CP}(K0 pi+) = -0.029 +/- 0.039 +/- 0.010.

Branching Fraction and CP Asymmetries of B0→KS0KS0KS0

We present measurements of the branching fraction and time-dependent CP-violating asymmetries in B0-->K0(S)K0(S)K0(S) decays based on 227 x 10(6) Upsilon4S-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We obtain a branching fraction of (6.9(+0.9)(-0.8)+/-0.6) x 10(-6), and CP asymmetries C=-0.34(+0.28)(-0.25)+/-0.05 and S=-0.71(+0.38)(-0.32)+/-0.04, where the first uncertainties are statistical and the second systematic.

Measurement of CP-Violating Asymmetries in B0 → (ρπ)0 Using a Time-Dependent Dalitz Plot Analysis

We present the preliminary measurement of CP-violating asymmetries in B0 → (ρπ)0 → π+π-π0 decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 213 million [Formula: see text] decays, collected by the BaBar detector at the PEPII asymmetric-energy B -Factory at SLAC. We measure 16 coefficients of the bilinear form factor terms occurring in the time-dependent decay rate of the B0 meson with the use of a maximum-likelihood fit. The physically relevant CP parameters are derived from these coefficients.

Measurement of Time-DependentCP-Violating Asymmetries inB0→K*0γK*0→KS0π0Decays

We present a measurement of the time-dependent CP-violating asymmetries in B0→K*0γ(K*0→KS0π0) decays based on 124×106 Υ(4S)→BB¯ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. In a sample containing 105±14 signal decays, we measure SK*γ=0.25±0.63±0.14 and CK*γ=−0.57±0.32±0.09, where the first error is statistical and the second, systematic.Received 31 May 2004DOI:https://doi.org/10.1103/PhysRevLett.93.201801©2004 American Physical Society

Observation of large CP violation and evidence for direct CP violation in B0-->pi(+)pi(-) decays.

We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value.

Study of CP-violating asymmetries in B0-->pi(+)pi(-) decays.

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).