Malcolm John

Abstract:

We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D* π±, using approximately 232×106 BB̄ events recorded by the BABAR experiment at the PEP-II e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum π± from the B decay and the low-momentum π from the D* decay are used. We measure the parameters related to 2β+γ to be aD*π=-0. 034±0.014±0.009 and cD*π =-0.019±0.022±0. 013. With some theoretical assumptions, we interpret our results in terms of the lower limits |sin (2β+γ)|>0.62(0.35) at 68% (90%) confidence level. © 2005 The American Physical Society.

Abstract:

We measure the time-dependent CP asymmetry parameters in B0→K+K-K0 based on a data sample of approximately 227×106 B-meson pairs recorded at the Υ(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. We reconstruct two-body B0 decays to (1020)KS0 and (1020)KL0, and the three-body decay K+K-KS0 with (1020)KS0 excluded. For the B0→K0 decays, we measure sin 2βeff(K0)=+0.50±0.25(stat)-0.04+0.07(syst). The B0→K+K-KS0 decays are dominated by K+K- S wave, as determined from an angular analysis; we measure sin 2βeff(K+K-KS0)=+0.55±0.22(stat) ±0.04(syst)±0.11(CP), where the last error is due to the uncertainty in the fraction of CP-even contributions to the decay amplitude. We find no evidence for direct CP violation. © 2005 The American Physical Society.

Abstract:

We report a search for B→J/ψD decays, based on a sample of 124×106 BB̄ events collected with the BABAR detector at the PEP-II storage ring of the Stanford Linear Accelerator Center. No significant signal is found. We obtain upper limits on the branching fractions of 1.3×10-5 for B0→J/ψD̄0 and 1.2×10-4 for B+→J/ψD+ at 90% confidence level. © 2005 The American Physical Society.

Abstract:

We report on a search for the CP asymmetry in the singly Cabibbo-suppressed decays D+→K-K+π+ and in the resonant decays D+→π+ and D+→K̄*0K+ based on a data sample of 79.9fb-1 recorded by the BABAR detector. We use the Cabibbo-favored Ds+→K-K+π+ branching fraction as normalization in the measurements to reduce systematic uncertainties. The CP asymmetries obtained are ACP(K-K+π±)=(1.4±1.0(stat)±0. 8(syst))×10-2, ACP(π±)=(0.2±1.5(stat)±0.6(syst)) ×10-2, and ACP(K̄*0K±)=(0.9±1.7(stat)±0. 7(syst))×10-2. The relative branching fraction Γ(D+→K-K+π+)/ Γ(D+→K-π+π+) is also measured and is found to be (10.7±0.1(stat)±0.2(syst))×10-2. © 2005 The American Physical Society.

Abstract:

We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 227 × 106 Y(4S) → BB̄ decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The amplitude of the CPasymmetry, sin2β in the standard model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0 from its decay products. We measure sir2β = 0.722 ±0.040(stat) ±0.023(syst) in agreement with the standard model expectation. © 2005 The American Physical Society.