We present a measurement of the time-dependent CP-violating (CPV) asymmetries in B0-->K(0)(S)pi(0) decays based on 124x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In a sample containing 122+/-16 signal decays, we obtain the magnitudes of the direct CPV asymmetry CK(0)(S)(pi(0))=0.40(+0.27)(-0.28)+/-0.09 and of the CPV asymmetry in the interference between mixing and decay SK(0)(S)(pi(0))=0.48(+0.38)(-0.47)+/-0.06 where the first error is statistical and the second systematic.

We present the result of a search for the charmless two-body baryonic decay B0→ppmacr; in a sample of 88 million Y(4S)→BB̄ decays collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. We use Cherenkov radiation to identify protons cleanly, and determine the signal yield with a maximum-likelihood fit technique using kinematic and topological information. We find no evidence for a signal and place a 90% confidence-level upper limit of B(B0→ pp̄)<2.7× 10-7. © 2004 The American Physical Society.

We present a measurement of the branching fraction for the decay B -→K0*- using a sample of approximately 86×106 BB̄ pairs collected by the BABAR detector from e+e- collisions near the γ(4S) resonance. The D0 is detected through its decays to K -π+, K-π+π0, and K- π+ π- π+, and the K*- through its decay to KS0π -. We measure the branching fraction to be B(B -→D0K*-) = [6.3±0.7(stat) ±0.5(syst)]×10-4. © 2004 The American Physical Society.

We have performed a search for the decays B+-->J/psip(-)Lambda; and search for B0-->J/psip(-)p. in a data set of (88.9+/-1.0) x 10(6) Upsilon(4S) decays collected by the BABAR experiment at the PEP-II e(+)e(-) storage ring at the Stanford Linear Accelerator Center. Four charged B candidates have been observed with an expected background of 0.21+/-0.14 events. The corresponding branching fraction is (12(+9)(-6)) x 10(-6), where statistical and systematic uncertainties have been combined. The result can be interpreted as a 90% confidence level (C.L.) upper limit of 26 x 10(-6). We also find one B0 candidate, with an expected background of 0.64+/-0.17 events, implying a 90% C.L. upper limit of 1.9 x 10(-6).

We present a measurement of the average multiplicity of φ mesons in [Formula Presented] [Formula Presented] and [Formula Presented] meson decays. Using 17.6 [Formula Presented] of data taken at the [Formula Presented] resonance by the BABAR detector at the PEP-II [Formula Presented] storage ring at the Stanford Linear Accelerator Center, we reconstruct φ mesons in the [Formula Presented] decay mode and measure [Formula Presented] This is significantly more precise than any previous measurement. © 2004 The American Physical Society.

We report the observation of the B meson decay B+/- -->J/psietaK+/- and evidence for the decay B0-->J/psietaK0S, using 90 x 10(6) BB; events collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II e+e- asymmetric-energy storage ring. We obtain branching fractions of B(B+/- -->J/psietaK+/-) = [10.8 +/- 2.3(stat) +/- 2.4(syst)] x 10(-5) and B(B0-->J/psietaK0S) = [8.4 +/- 2.6(stat) +/- 2.7(syst)] x 10(-5). We search for the new narrow mass state, the X(3872), recently reported by the Belle Collaboration, in the decay B+/- -->X(3872)K+/-,X(3872)-->J/psieta and determine an upper limit of B[B +/- -->X(3872)K+/- -->J/psietaK+/-] < 7.7 x 10(-6) at 90% confidence level.