Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

A Precision Measurement of the Lambda_c Baryon Mass

The $\Lambda_c^+$ baryon mass is measured using $\Lambda_c^+\to\Lambda K^0_S K^+$ and $\Lambda_c^+\to\Sigma^0 K^0_S K^+$ decays reconstructed in 232 fb$^{-1}$ of data collected with the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ storage ring. The $\Lambda_c^+$ mass is measured to be $2286.46\pm0.14\mathrm{MeV}/c^2$. The dominant systematic uncertainties arise from the amount of material in the tracking volume and from the magnetic field strength.Comment: 14 pages, 8 postscript figures, submitted to Phys. Rev.

Measurement of branching fractions and resonance contributions for B-0 ->(D)over-bar(0)K(+)pi(-) and search for B-0 ->(DK+)-K-0 pi(-) decays

Using 226x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for B-0->(D) over bar (0)K(+)pi(-), excluding B-0-> D*-K+, to be B(B-0->(0)K(+)pi(-))=(88 +/- 15 +/- 9)x10(-6). We observe B-0->(D) over bar K-0(*)(892)(0) and B-0-> D-2(*)(2460)K--(+) contributions. The ratio of branching fractions B(B-0-> D*-K+)/B(B-0-> D(*-)pi(+))=(7.76 +/- 0.34 +/- 0.29)% is measured separately. The branching fraction for the suppressed mode B-0-> D(0)K(+)pi(-) is B(B-0-> D(0)K(+)pi(-))< 19x10(-6) at the 90% confidence level

Observation of B-0 meson decay to a(1)(+/-)(1260)pi(-/+)

We present a measurement of the branching fraction of the decay B-0 -> a(1)(+/-)(1260)pi(-/+) with a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-). The data sample corresponds to 218x10(6) B (B) over bar pairs produced in e(+)e(-) annihilation through the Upsilon(4S) resonance. We measure the branching fraction B(B-0 -> a(1)(+/-)(1260)pi(-/+))B(a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-))=(16.6 +/- 1.9 +/- 1.5)x10(-6), where the first error quoted is statistical and the second is systematic

Determinations of vertical bar V-ub vertical bar from inclusive semileptonic B decays with reduced model dependence

We report two novel determinations of vertical bar V-ub vertical bar with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Y(4S) -> B (B) over bar events. In one approach, we combine the inclusive (B) over bar -> X(u)l (v) over bar rate, integrated up to a maximum hadronic mass m(X) X-s gamma photon energy spectrum. We obtain vertical bar V-ub vertical bar = (4.43 +/- 0.38(stat) +/- 0.25(syst) +/- 0.29(theo)) x 10(-3). In another approach we measure the total (B) over bar -> X(u)l (v) over bar rate over the full phase space and find vertical bar V-ub vertical bar = 3.84 +/- 0.70(stat) +/- 0.30(syst) +/- 0.10(theo)) x 10(-3)

Observation of a Charmed Baryon Decaying to D0p at a Mass Near 2.94 GeV/c2

A search for charmed baryons decaying to D 0 p reveals two states: the Λ c ( 2880 ) + baryon and a previously unobserved state at a mass of [ 2939.8 ± 1.3 ( stat ) ± 1.0 ( syst ) ]     MeV / c 2 and with an intrinsic width of [ 17.5 ± 5.2 ( stat ) ± 5.9 ( syst ) ]     MeV . Consistent and significant signals are observed for the K − π + and K − π + π − π + decay modes of the D 0 in 287     fb − 1 annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D + p spectrum of doubly charged partners. The mass and intrinsic width of the Λ c ( 2880 ) + baryon and relative yield of the two baryons are also measured

Measurement of branching fractions and charge asymmetries in B decays to an eta meson and a K-* meson

We present measurements of branching fractions and charge asymmetries for the decays B ->eta K-*, where K-* indicates a spin 0, 1, or 2 K pi system. The data sample corresponds to 344x10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We measure the branching fractions (in units of 10(-6)): B(B-0 ->eta K-*0(892))=16.5 +/- 1.1 +/- 0.8, B(B+->eta K*+(892))=18.9 +/- 1.8 +/- 1.3, B(B-0 ->eta(K pi)(0)(*0))=11.0 +/- 1.6 +/- 1.5, B(B+->eta(K pi)(0)(*+))=18.2 +/- 2.6 +/- 2.6, B(B-0 ->eta K-2(*0)(1430))=9.6 +/- 1.8 +/- 1.1, and B(B+->eta K-2(*+)(1430))=9.1 +/- 2.7 +/- 1.4. We also determine the charge asymmetries for all decay modes

Measurements of branching fractions and dalitz distributions for B-0 ->(DK0)-K-(*)+/-pi(-/+) decays

We present measurments of the branching fractions for the three-body decays B-0 -> D((*) -/+)K(0)pi(+/-) and their resonant submodes B0 -> D(*)K-/+*(+/-) usinga sample of approximately 88 x 10(6) B (B) over bar pairs collected by the BABER detector at the SLAC PEP-II assymetric energy storage ring. We measure: B(B-0-> D(-/+)K(0)pi(+/-)) = (4.9 +/- 0.7(stat) +/- 0.5(syst)) x 10(-4), B(B-0 -> D*(-/+)K(0)pi(+/-)) = (3.0 +/- 0.7(stat) +/- 0.3(syst)) x 10(-4), B(B-0 -> D-/+K*(+/-)) = (4.6 +/- 0.6(stat) +/- 0.5(syst)) x 10(-4), B(B-0 -> D*K-/+*(+/-) = (3.2 +/- 0.6(stat) +/- 0.3(syst)) x 10(-4). From these measurements we determine the fractions of resonant events to be f(B0 -> D+/-K*(-/+)) = 0.63 +/- 0.08(stat) +/- 0.04(syst) and f(B-0 -> D*K-/+*(+/-)) = 0.72 +/- 0.14(stat) +/- 0.05(syst)

Measurement of the CP asymmetry and branching fraction of B-0 ->rho K-0(0)

We present a measurement of the branching fraction and time-dependent CP asymmetry of B-0 -> POKO. The results are obtained from a data sample of 227 x 10(6) Y(4S) -> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at Stanford Linear Accelerator Center. From a time-dependent maximum likelihood fit yielding 111 +/- 19 signal events, we find B(B-0 -> rho K-0(0)) = (4.9 +/- 0.8 +/- 0.9) x 10(-6), where the first error is statistical and the second systematic. We report the measurement of the CP parameters S-rho 0KS0 = 0.20 +/- 0.52 +/- 0.24 and C-rho 0KS0 = 0.64 +/- 0.41 +/- 0.20