Search for the rare decays B^0 → D_s^((*)+)a-_(0(2))

We have searched for the decays B^0 → D_s^+a^-_0, B^0 → D_s^(*+)a^-_0, B^0 → D_s^+a^-_2 and B^0 → D_s^(*+)a^-_2 in a sample of about 230 × 10^6 Υ(4S) → BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find no evidence for these decays and set upper limits at 90% C.L. on the branching fractions: B(B^0 → D_s^+a^-_0)<1.9 × 10^(-5), B(B^0 → D_s^(*+)a^-_0)<3.6 × 10^(-5), B(B^0 → D_s^+a^-_2)<1.9 × 10^(-4), and B(B^0 → D_s^(*+)a^-_2)<2.0 × 10^(-4)

Measurement of CP observables for the decays B^± → D^0_(CP)K^±

We present a study of the decay B^- → D^0_(CP)K^± and its charge conjugate, where D^0_CP) is reconstructed in CP-even, CP-odd, and non-CP flavor eigenstates, based on a sample of 232 x 10^6 Y(4S) → BB decays collected with the BABAR detector at the PEP-II e^+e^- storage ring. We measure the partial-rate charge asymmetries A_(CP±) and the ratios R_(CP±) of the B → D^0K decay branching fractions as measured in CP^± and non-CP D^0 decays: A_(CP±) 0:35 ± 0.13(stat) ± 0.04(syst), A_(CP-)= -0.06 ± 0.13(stat) ± 0.04(syst), R_(CP+) = 0.90 ± 0.12(stat) ± 0.049syst), and R_(CP-) = 0:86 ± 0.10(stat) ± 0.05(syst)

Measurements of the Absolute Branching Fractions of B^±→K^±X_(cc)

We study the two-body decays of B^± mesons to K^± and a charmonium state X_cc in a sample of 210.5  fb^(-1) of data from the BABAR experiment. We perform measurements of absolute branching fractions B(B^±→K^±X_(cc)) using a missing mass technique, and report several new or improved results. In particular, the upper limit B(B^±→K^±X(3872))4.2% will help in understanding the nature of the recently discovered X(3872)

Measurement of the inclusive electron spectrum in charmless semileptonic B decays near the kinematic end point and determination of │V_(ub)│

We present a measurement of the inclusive electron spectrum in B → X_ueν decays near the kinematic limit for B → X_ceν transitions, using a sample of 88 × 10^6 BB pairs recorded by the BABAR detector at the Υ (4S resonance. Partial branching fraction measurements are performed in five overlapping intervals of the electron momentum; for the interval of 2.0 – 2.6 GeV/c we obtain ΔB (B → X_ueν) = (0.572 ± 0.041_(stat) ± 0.065_(syst)) × 10^(−3). Combining this result with shape function parameters extracted from BABAR measurements of moments of the inclusive photon spectrum in B → X_sγ decays and moments of the hadron-mass and lepton-energy spectra in B → X_cℓν decays we determine │Vub|= (4.44 ± 0.25 + 0.4_( exp−0.38SF) ± 0.22_(theory)) × 10^(−3). Here the first error represents the combined statistical and systematic experimental uncertainties of the partial branching fraction measurement, the second error refers to the uncertainty of the determination of the shape function parameters, and the third error is due to theoretical uncertainties in the QCD calculations

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

The Physics of the B Factories

“The Physics of the B Factories” describes a decade long effort of physicists in the quest for the precise determination of asymmetry — broken symmetry — between particles and anti-particles. We now recognize that the matter we see around us is the residue — one part in a billion — of the matter and antimatter that existed in the early universe, most of which annihilated into the cosmic background radiation that bathes us. But the question remains: how did the baryonic matter-antimatter asymmetry arise? This book describes the work done by some 1000 physicists and engineers from around the globe on two experimental facilities built to test our understanding of this phenomenon, one at the SLAC National Accelerator Laboratory in California, USA, and a second at the KEK Laboratory, Tsukuba, Japan, and what we have learned from them in broadening our understanding of nature

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Search for decays of B-0 -> e(+)e(-), B-0 -> mu(+)mu(-), B-0 -> e(+/-)mu(-/+)

We present a search for the decays B-0 -> e(+)e(-), B-0 ->mu(+)mu(-), and B-0 -> e(+/-)mu(-/+) in data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC B Factory. Using a data set of 111 fb(-1), we find no evidence for a signal in any of the three channels investigated and set the following branching fraction upper limits at the 90% confidence level: B(B-0 -> e(+)e(-))mu(+)mu(-)) e(+/-)mu(-/+))< 18x10(-8)

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