Malcolm John

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.

Abstract:

We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/ψ, ψ(2S) and χc1, and the light meson is either K or K*. We use a sample of about 124 × 10⁶ BB̄ pairs collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. © 2005 The American Physical Society.

Abstract:

We search for the decay B⁰ → ρ⁰ρ ⁰ in a data sample of about 227 × 10⁶ Γ(4S) → B B̄ decays collected with the BABAR detector at the PEP-II asymmetric-energy e⁺ e^- collider at SLAC. We find no significant signal and set an upper limit of 1.1 × 10^-6 at 90% C.L. on the branching fraction. As a result, the uncertainty due to penguin contributions on the Cabibbo-Kobayashi-Maskawa unitarity angle α measured in B → ρρ decays is decreased to 11° at 68% C.L. © 2005 The American Physical Society.

Abstract:

We study the decay B^- → J/ΨK ^-π⁺π^- using 117×10⁶ BB̄ events collected at the Y(4S) resonance with the BABAR detector at the PEP-II e⁺e^- asymmetric-energy storage ring. We measure the branching fractions ℬ (B^- → J/ΨK ^-π⁺π^-) = (116±7(stat.) ±9(syst.))×10^-5 and ℬ (B^- → X(3872)K^-) × ℬ (X(3872) → J/Ψπ⁺π ^-) = (1.28±0.41)×10^-5 and find the mass of the X(3872) to be 3873.4±1.4 MeV/c². We search for the h c narrow state in the decay B^- → hcK ^-, hc → J/Ψπ⁺π^- and for the decay B^- → J/ΨD⁰π^-, with D⁰ → K^-π⁺. We set the 90% C.L. limits ℬ(B^- → hcK^-) × ℬ(h c → J/Ψπ⁺π^-)<3. 4×10^-6 and ℬ(B^- → J/ΨD ⁰π^-)<5.2×10^-5. © 2005 The American Physical Society.