Malcolm John

Abstract:

We analyze the decay B0→KS0π+π- using a sample of 232×106 Υ(4S)→BB̄ decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. A maximum likelihood fit finds the following branching fractions: B(B0→K0π+π-)=(43.0±2.3±2.3) ×10-6,B(B0→f0(→π+π-)K0)=(5.5±0.7±0. 5±0.3)×10-6 and B(B0→K*+π-)=(11.0±1. 5±0.5±0.5)×10-6. For these results, the first uncertainty is statistical, the second is systematic, and the third (if present) is due to the effect of interference from other resonances. We also measure the CP-violating charge asymmetry in the decay B0→K*+π-, AK*π=-0. 11±0.14±0.05. © 2006 The American Physical Society.

Abstract:

We study the two-body decays of B± mesons to K± and a charmonium state Xcc̄ in a sample of 210.5fb-1 of data from the BABAR experiment. We perform measurements of absolute branching fractions B(B±→K±Xcc̄) using a missing mass technique, and report several new or improved results. In particular, the upper limit B(B±→K±X(3872))<3.2×10-4 at 90% C.L. and the inferred lower limit B(X(3872)→J/ψπ+π-)>4.2% will help in understanding the nature of the recently discovered X(3872). © 2006 The American Physical Society.

Abstract:

We present measurements of the branching fraction and time-dependent CP asymmetries in B0→J/ψπ0 decays based on (231.8±2.6) ×106Υ(4S)→BB̄ decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We obtain a branching fraction B(B0→J/ψπ0)=(1.94±0.22(stat)±0.17(syst))×10-5. We also measure the CP asymmetry parameters C=-0.21±0.26(stat)±0. 06(syst) and S=-0.68±0.30(stat)±0.04(syst). © 2006 The American Physical Society.

Abstract:

We present measurements of branching fractions of B0 decays to multibody final states containing protons, based on 232×106 Υ(4S)→BB̄ decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We measure the branching fractions B(B0→D̄0pp̄)=(1. 13±0.06±0.08)×10-4, B(B0→D̄*0pp̄)=(1. 01±0.10±0.09)×10-4, B(B0→D-pp̄π+)=(3. 38±0.14±0.29)×10-4, and B(B0→D*-pp̄π+)= (4.81±0.22±0.44)×10-4 where the first error is statistical and the second systematic. We present a search for the charmed pentaquark state, Θc(3100) observed by H1 and put limits on the branching fraction B(B0→Θcp̄π+)×B(Θc→D*-p) <14×10-6 and B(B0→Θcp̄π+)×B(Θc→D-p) <9×10-6. Upon investigation of the decay structure of the above four B0 decay modes, we see an enhancement at low pp̄ mass and deviations from phase-space in the D̄p̄ and D̄p invariant mass spectra. © 2006 The American Physical Society.

Abstract:

We measure the dependence of B̄0→D*+e-ν̄e on the decay angles and momentum transfer. The data sample consists of ∼86×106 BB̄-pairs accumulated on the Υ(4S) resonance by the BABAR detector at the asymmetric e+e- collider PEP-II. We specify the three form factors by two ratios R1 and R2, and by a single parameter ρ2 characterizing the polynomial representing hA1, the function which describes the momentum-transfer dependence of the form factor A1. We determine R1, R2, and ρ2 using an unbinned maximum likelihood fit to the full decay distribution. The results are R1=1.396±0.060±0.035±0.027, R2=0.885±0.040±0.022±0.013, and ρ2=1.145±0. 059±0.030±0.035. The stated uncertainties are the statistical from the data, statistical from the size of the Monte Carlo sample and the systematic uncertainty, respectively. In addition, based on this measurement, we give an updated value for the CKM matrix element |Vcb|. © 2006 The American Physical Society.