We search for the purely leptonic decay $B^{\pm} \to μ^{\pm} ν_μ$ in the full BaBar dataset, having an integrated luminosity of approximately 426 fb$^{-1}$. We adopt a fully inclusive approach, where the signal candidate is identified by the highest momentum lepton in the event and the companion $B$ is inclusively reconstructed without trying to identify its decay products. We set a preliminary upper limit on the branching fraction of $\BR(B^{\pm} \to μ^{\pm} ν_μ) < 1.3 \times 10^{-6}$ at the 90% confidence level, using a Bayesian approach.
Using 8.5M B-anti-B events recorded by the BABAR detector the yield of inclusive J/psi, the branching ratios of psi(2S) and chi_C1 are presented. Combining the charmonium state with either a K+,KS, K*+ or K*0 exclusive B decays are reconstructed and their branching ratios determined. Using the fully reconstructed decays, both the B0 and B+ masses and their difference is measured. Finally the contributions of CP even and odd amplitudes in the decay B to J/psi K* are determined from an angular analysis.
We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B -> Xs l+l-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive B -> Xs gamma decays. We present the first result on the CP asymmetry difference of charged and neutral B -> Xs gamma$ decays yielding the first constraint on the ratio of Wilson coefficients Im (C8/C7).
We present measurements of the inclusive semileptonic branching fractions of charged and neutral B mesons using 20.6 fb-1 of data measured at the Upsilon(4S) with the BABAR detector. Events are tagged with a fully reconstructed hadronic decay of a B meson. The correlation between the flavor of the tag B meson and the electron charge allows the separation of prompt semileptonic B decays and cascade semileptonic charm decays. We obtain the preliminary inclusive semileptonic branching fraction of charged B mesons b+ = 0.103+/-0.006+/-0.005, neutral B mesons b0 = 0.104+/-0.008+/-0.005, their avera…
We present a preliminary measurement of the Collins asymmetries in the inclusive process e^+e^- --> qqbar --> pi pi X at center-of-mass energy near 10.6 GeV. We use a data sample of 468 fb^(-1) collected by the BABAR experiment, and we consider pairs of charged pions produced in opposite jets in hadronic events. We confirm a non-zero Collins effect as observed by previous experiments, and we study the Collins asymmetry as a function of pion fractional energies and transverse momenta, and as a function of the polar angle of the analysis axis.
A measurement of the first four moments of the hadronic mass distribution in B->Xc lv decays is presented for minimum lepton momenta varying between 0.9 and 1.6 GeV, using data recorded with the BaBar detector. Furthermore, a measurement of the inclusive electron energy spectrum for semileptonic B decays together with a measurement of its first, second and third moments for minimum electron energies between 0.6 and 1.5 GeV is reported. We determine the inclusive B->Xc lv branching fraction, B_clv, the CKM matrix element |V_cb|, and other heavy-quark parameters from a simultaneous fit to the me…
We report updates on two analyses of inclusive semileptonic B decays based on a dataset of 89 million BB events recorded with the BABAR detector at the Y(4S) resonance. 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. In the first analysis, the measurement of the first and second moment of the hadronic mass distribution in Cabibbo-favored B ->X_c l nu decays allows for the determination of the nonperturbative parameters $\barΛ$ and $λ_1$ of Heavy Quark Effective Theory (HQET) and |Vcb|. In the second anal…
BABAR results are presented for B -> Xs gamma decays, including branching fraction and photon spectrum measurements from both a fully inclusive analysis and a semi-inclusive analysis that reconstructs 38 distinct final states for Xs.
We present measurements of Collins asymmetries in the inclusive process e+e- -->pi pi X, where pi stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb-1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and moment…
We present preliminary results from a lepton-tagged fully-inclusive measurement of $B \to X_{s}γ$ decays, where $X_{s}$ is any strange hadronic state. Results are based on a BaBar data set of 88.5 million $B\bar{B}$ pairs at the $Υ(4S)$ resonance. We present a reconstructed photon energy spectrum in the $Υ(4S)$ frame, and partial branching fractions above minimum reconstructed photon energies of 1.9, 2.0, 2.1 and 2.2 GeV. We then convert these to measurements of partial branching fractions and truncated first and second moments of the true photon energy distribution in the B rest frame, above …
The status of analysis of processes with hard photon emitted from the initial state (ISR) at BABAR is presented. We tag events by the presence of a hard photon in the detector, then reconstruct mu+mu- and several exclusive hadronic final states. The invariant mass of the final state determines an effective collision center of mass energy at which these measurements can be compared with results from direct e+e- annihilation process. The first results on e+e- --> 2h+2h-, where h=pi,K and on e+e- --> J/psi, obtained with a sample of 89.3/fb, are presented. Measurements of inclusive eta, pi+, K+ a…
Inclusive hadron production cross sections in e+e-collisions shed light on the fundamental fragmentation and hadronization processes. We present measurements of the inclusive spectra of charged pions, kaons and protons in hadronic events at a center-of-mass energy of 10.54 \gev. These results are compared with theoretical predictions and the predictions of three hadronization models. Along with previous measurements at higher energies, they are also used to study the scaling properties of hadron production.
BaBar measurements involving semileptonic decays of B mesons are reviewed. Attention is focused on the extraction of |Vub| and |Vcb| elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Recent results of inclusive and exclusive approaches are presented.
Presented are selected results of semileptonic B decays at BaBar. Two measurements of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ are reported. One using moments of the hadronic-mass spectrum in inclusive $\bar{B} \to X_{c} \ell^{-} \barν$ decays, and the other, exclusive $\bar{B} \to D \ell^- \barν_{\ell}$ decays. These results are based on data samples of 232 (inclusive $\bar{B} \to X_{c} \ell^{-} \barν$) and 460 (exclusive $\var{B} \to D \ell^- \barν_{\ell}$) million $Υ(4S) \to B\bar{B}$ decays, recorded by the $BaBar$ detector at the PEP-II $e^+e^-$-storage rings. Semileptonic …
We review hadron spectroscopy at BABAR with emphasis on recent results from the studies of the X(3872) state, inclusive charmonia on recoil, double charmonium production, and the broad structure observed at around 4.26 GeV/c^2. These results are preliminary, unless otherwise specified.
Radiative and electroweak decays of B mesong (B to X_{s(d)}γ and B to X_{s(d)}\ell\ell, respectively, where X is a hadronic system and s or d labels the underlying quark process b to s(d)γ) provide good places to search for new physics (NP) beyond the standard model. Recent BaBar measurements are reported: inclusive BF(B to X_s γ), direct CP asymmetry for inclusive X_s γ and X_{s+d} γ, and searches for the rare decays B to π(η)\ell\ell. No evidence for NP was found, but several constraints are discussed.
We present recent results from the \babar Collaboration on radiative decays. These include searches for new physics via measurements of several observables such as the time-dependent $CP$ asymmetry in $B^0 \to K^0_S π^- π^+ γ$ exclusive decays, as well as direct $CP$ asymmetries and branching fractions in $B \to X_s γ$ and $B \to X_s \ell^+ \ell^-$ inclusive decays.
Recent BaBar measurements on lifetime and mixing of B mesons are reported. Various techniques are used, ranging from the full reconstruction of hadronic B decays, to partial reconstruction techniques, and to a totally inclusive approach with dilepton events. The results presented are based on a data sample collected by BaBar during the 1999-2000 data taking, and should be considered as preliminary.
Some recent Babar results on semileptonic decays are presented. They focus on the determination of the CKM matrix elements |V_{ub}| and |V_{cb}| in inclusive and exclusive b --> u l nu and b--> c l nu decays, and on form factors measurement in exclusive c--> s l nu decays.
Using 22.7 million BBbar events recorded with the BABAR detector, the inclusive branching fractions for the production of J/psi, psi(2S) and Chi_c in B decays are presented. Combining the charmonium state with a K+-, K0, K*+-, K*0 or neutral pion, B decays are reconstructed exlusively and branching fractions are determined. A preliminary study is also presented fot the B --> eta_c K decay mode.
Studies of semileptonic $B_s$ decays by the Belle, Babar and D0 experiments are reported. In particular measurements of inclusive semileptonic $B_s$ decays by Belle and Babar and the exclusive excited charm mode $B_s \to D_{s1} μν$ from D0 are presented. An outlook on further semileptonic $B_s$ measurements with $Υ(5S)$ data at Belle and Belle II is also given.
We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V_{cb}| and |V_{ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.
Based on a data sample of 81.7 fb^-1 collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we present the current status of the measurement of the branching fraction of Upsilon(4S) to B0bar B^0. Our study of the decay was performed through the exclusive decays B0bar to D^{*+} \ell^{-} barν_{\ell} using a partial reconstruction method, where the D^{*+} is detected only through the soft pion daughter from the decay D^{*+} to D^{0} pi^{+}.
We report measurements of charmonium resonances (J/Psi, Psi(2S),Chi_c1) using about 25 fb^-1 of data collected by the BABAR detector around the Upsilon(4S) resonance. We present measurements of inclusive charmonium production of charmonium in B decays and from the continuum, as well as exclusive branching ratios of B mesons into charmonium final states. We present also a measurement of the B0 -> K*0 gamma branching ratio and a search for the decay B0 -> gamma gamma.
This paper presents the results of inclusive searches for the strange pentaquark states $Θ^+(1540)$, $Ξ_5^{--}(1860)$ and $Ξ_5(1860)^{0}$ as well as the anti-charm pentaquark state $Θ_c(3099)^{0}$ in a dataset of 123.4 fb$^{-1}$ collected on and 40$ $MeV below the $Υ(4S)$ resonance by the BABAR detector at the $e^+e^-$ PEPII storage rings. No evidence for the pentaquark states is found and upper limits on the rate of $Θ^+(1540)$ and $Ξ_5^{--}(1860)$ production in $e^+e^-$ annihilation are obtained.
A mini-review of measurements of inclusive semileptonic $B \to X_c\ellν$ and radiative $B\to X_sγ$ decays is presented. The semileptonic $X_c$ mass moments are presented from Belle and BABAR. The inclusive $B\to X_sγ$ gamma branching fraction is presented from Belle as well as a preliminary measurement of the direct CP-asymmetry of $B \to X_{s+d}γ$ decays at BABAR. Fundamental Standard Model parameters and heavy quark parameters can be derived from the $X_c$ mass and lepton energy moments from $B \to X_c\ellν$ decays and from the photon energy moments from $B \to X_sγ$ decays. The values of th…
We present results from BABAR experiment for the measurement of inclusive and exclusive branching fractions of B mesons into final states containing $J/ψ$, $ψ(2S)$ and $χ_c$. The contributions of CP even and odd amplitudes in the decay $B^0 \to J/ψK^{*0}$ are determined from an angular analysis. We report the measurements of the branching ratios $B^0 \to D^{*+}D^{*-}$ and $D^{*+}D^{*-}K^0_S$, and the study of exclusive two-body and quasi-two-body charmless decays. The branching fraction of the decay $B^0 \to K^{*0} γ$ has been determined and the corresponding CP asymmetry has been measured.
We present recent results of B and charm decays from the BaBar experiment. These results include searches for rare or forbidden charm decays, measurements of $|V_{ub}|$ from inclusive ${\bar B} \rightarrow X_u l {\bar ν} $ decays, observation of the semileptonic ${\bar B} \rightarrow D^{(*)} τ^- {\bar ν}_τ$ decays, direct CP violation asymmetry in $B \rightarrow X_{s+d} γ$ and in $D^+\rightarrow K^0_S π^+$, and T-violation in $D^+_{(s)} \rightarrow K^+ K^0_S π^+ π^-$. These studies are based on the final dataset collected by BaBar at the PEP-II B factory at SLAC in the period 1999-2008.
In this article, I review the recent results for inclusive and exclusive measurements for $b\to sγ$ and $b\to dγ$ decays from $B$ factories Belle and Babar. I describe the measurement of branching fraction and direct CP violating asymmetry for inclusive $B\to X_sγ$ decay. For results of $b\to dγ$ process, I introduce the measurement of branching fraction of exclusive $b\to dγ$ modes, the first measurement for CP asymmetry of $b\to dγ$ process using $B\toργ$ mode, and semi-inclusive measurement for $B\to X_dγ$.
The results of searches for the strange pentaquark states, Theta(1540)+, Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are presented. We search for these three states inclusively in 123.4 fb^-1 of e+ e- annihilation data produced at the PEP-II asymmetric storage rings; we find no evidence for their production in any physics process, and set limits on their production rates that are well below the measured rates for conventional baryons. We also search for Theta(1540)+ produced in interactions of electrons or hadrons in the material of the inner part of the detector. No evid…
We present a measurement of the inclusive electron spectrum in charmless semileptonic B decays near the kinematic limit for B->X_c eνtransitions, using a sample of 88 million Upsilon(4S) decays recorded by the BABAR detector. 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 ΔBr(B->X_u eν) = (0.572+-0.041(stat)+-0.065(syst))x10^{-3}. Combining this result with shape function parameters extracted from BABAR measurements of moments of the inclusive photon spectrum in B->X_s+gamma decays and mo…
The inclusive production of charmonium mesons in B meson decay has been studied in a 20.3 fb$^{-1}$ data set collected by the BaBar experiment operating at the $Υ(4S)$ resonance. Branching fractions have been measured for the inclusive production of the charmonium mesons $J/ψ$, $ψ(2S)$, $χ_{c1}$, and $χ_{c2}$. The branching fractions are also presented as a function of the center-of-mass momentum of the mesons and of the helicity of the $J/ψ$.
We present results on semileptonic B decays obtained with the BABAR detector. The large data set accumulated at the PEP-II asymmetric-energy B-Factory allows a new measurement technique, where the hadronic decay of one B meson is fully reconstructed and the semileptonic decay of the recoiling B meson is studied. Traditional analysis techniques of inclusive and exclusive B decays complement this approach with very high statistics data samples. These measurements play an important role in the tests of the description of CP violation in the Standard Model: The determinations of the Cabibbo-Kobaya…
A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the Upsilon(4S) resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is BR(B -> X e nu) = (10.87 +-0.18(stat)+-0.30(syst))%. Based on this measurement we determine the CKM matrix element |V_cb|.
We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million Y4S -> BBar decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cut-offs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be Br(B -> X e nu, E_e>0.6 GeV) = (10.36 +-0.06(stat.) +-0.23(sys))%.
We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BaBar detector. The first two studies measure the tracking efficiency of a charged particle using $τ$ and initial state radiation decays. The third uses the $τ$ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of $K_S^0$ particles. The first section also examines the stability of the measurements vs BaBar running periods.
We reconstruct the charmonium mesons J/psi, psi(2S) and chi_C1 using a sample of 8.46 x 10^6 B-anti-B events collected by the BABAR detector operating at e^+e^- center of mass energies near the Y(4S) resonance. By measuring rates relative to the branching fraction of the J/psi, we obtain preliminary inclusive B branching fractions of (0.25+/-0.02+/-0.02)% to the psi(2S) and (0.39+/-0.04+/-0.04)% to the chi_C1, and set a 90% confidence level limit of 0.24% on decays through the chi_C2.
The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million $\B\bar B$ pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $Δm_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.
A study of the $D_{sJ}^*(2317)^+$ and $D_{sJ}(2460)^+$ mesons in inclusive $c\bar{c}$ production is presented using 232 ${\rm fb}^{-1}$ of data collected by the BaBar experiment near $\sqrt{s} = 10.6$ \gev. Final states consisting of a $D_s^+$ meson along with one or more $π^0$, $π^\pm$, or $γ$ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the $D_{s1}(2536)^+$ meson. A search is also performed for neutral and doubly-charged partners of the $D_{sJ}^*(2317)^+$ meson.
We report on recent measurements of the branching fractions (BFs) for the decay channels B^0 -> π^-ł^+ν, B^+ -> π^0ł^+ν, B^+ -> ηł^+ν, B^+ -> η'ł^+ν, B^0 -> ρ^-ł^+ν and B^+ -> ρ^0ł^+ν. We obtain very precise values of the total branching fractions for these decays, as well as partial branching fractions as a function of q^2 for the decay channels B^0 -> π^-ł^+ν, B^+ -> ηł^+ν and B^0 -> ρ^-ł^+ν. In particular, we use the partial branching fractions of the B^0 -> π^-ł^+ν decay channel and form-factor calculations to extract several values of |V_{ub}|. When we compared these values of |V_{ub}| to…
We present a study of the $D^+π^-$, $D^0π^+$, and $D^{*+}π^-$ systems in inclusive $e^+e^- \rightarrow c\bar{c}$ interactions in a search for new excited $D$ meson states. We use a dataset, consisting of $\sim$454 fb$^{-1}$, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. We observe, for the first time, candidates for the radial excitations of the $D^0$, $D^{*0}$, and $D^{*+}$, as well as the L=2 excited states of the $D^0$ and $D^+$, where $L$ is the orbital angular momentum of the quarks.
We present preliminary results from a search for inclusive charmless B->KX decays. These decays occur dominantly via one-loop b->s penguin transitions, and can provide useful information about these processes. Using a sample of 288.5/fb collected with the BABAR detector at the PEP-II asymmetric-energy e+e- B Factory at SLAC, we search for high-energy kaons recoiling against fully reconstructed B decays. We measure the partial branching fractions for kaons with momentum p*(K)>2.34GeV in the B rest frame, and obtain (in units of 10^-6): B(B->K+X, p*>2.34GeV) = 196^{+37}_{-34}(stat.)^{+31}_{-30}(…
We report the results of a search for T and CP violation in B0-anti-B0 mixing using an inclusive dilepton sample collected by the BaBar experiment at the PEP-II B Factory. The asymmetry between (l+,l+) and (l-,l-) events allows us to compare the probabilities P(anti-B0 -> B0) and P(B0 -> anti-B0) oscillations and thus probe T and CP invariance. Using a sample of 23 million B-anti-B pairs, we measure a same-sign dilepton asymmetry of A_(T/CP)=(0.5 +- 1.2(stat) +- 1.4(syst))%. For the modulus of the ratio of complex mixing parameters p and q, we obtain |q/p| = 0.998 +- 0.006(stat) +- 0.007(syst)…
Electron-positron annihilation data collected by the BABAR detector near the Y(4S) resonance are used to study the inclusive decay of B mesons to D_S^(+/-) and D_S^(*+/-) mesons, where the D_S^(+/-) is reconstructed using the decay D_S^(+/-) --> phi pi^(+/-). The production fraction of inclusive D_S^((*)+/-) and the corresponding momentum spectra have been determined. The exclusive decays B^0 --> D^(*-)D_S^((*)+) are observed with a partial reconstruction technique which uses the soft pion from the D^(*+/-) decay in association with the reconstructed D_S^((*)+/-). The beam energy constraint is…
With an integrated luminosity of 7.7 fb-1 collected on resonance by BABAR at the PEP-II asymmetric B Factory, we measure the difference in mass between the neutral B eigenstates, Delta(m_d), to be (0.507+/-0.015+/-0.022)x 10^{12} hbar s^{-1} with dileptons events and present preliminary results for the B^0 lifetime, tau(B^0) = 1.55+/-0.05+/-0.07 ps and tau(B^0) = 1.62+/-0.02+/-0.09 ps obtained from partial reconstruction of the two B^0 decay processes respectively B^0-->D^{*-}pi^+ and B^0-->D^{*-} l^+ nu_l.
We observe the decays $ $D^*_{s1}(2710)^+ \to D^*K$ and $D^*_{sJ}(2860)^+ \to D^*K$ and measure their branching fractions relative to the $D K$ final state. We also observe, in the $D^*K$ mass spectrum, a new broad structure at a mass of $(3044 \pm 8_{stat} (^{+30}_{-5})_{syst})$ $MeV/c^2$ having a width $Γ=(239 \pm 35_{stat} (^{+46}_{-42})_{syst})$ $MeV$. To obtain this result we use 470 ${\rm fb}^{-1}$ of data recorded by the BaBar detector at the PEPII asymmetric-energy $e^+e^-$ storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.
We present a study of the inclusive $D^{*\pm}$ production in the decay of $Υ(1S)$ using $(98.6 \pm 0.9)\times 10^6$ $Υ(2S)$ mesons collected with the BaBar detector at the $Υ(2S)$ resonance. Using the decay chain $Υ(2S)\to π^+ π^- Υ(1S), Υ(1S) \to D^{*\pm} X$, where X is unobserved, we measure the branching fraction $\BR[Υ(1S)\to D^{*\pm} X] = (2.52 \pm 0.13({\rm stat}) \pm 0.15({\rm syst}))%$ and the $D^{*\pm}$ momentum distribution in the rest frame of the $Υ(1S)$. We find evidence for an excess of $D^{*\pm}$ production over the expected rate from the virtual photon annihilation process $Υ(1…
We report a measurement of the rate for $B \to η' X_s$ transitions where the $η'$ meson has center-of-mass momentum in the range 2.0 to 2.7\gevc and $X_s$ represents a system comprising a kaon and up to four pions. Our study is based on 22.2 million $B\bar{B}$ pairs collected at the $Υ(4S)$ with the BABAR detector at the Stanford Linear Accelerator Center. We find $\mathcal{B}(B \to η' X_s)=(6.8^{+0.7}_{-1.7}(stat)\pm1.0(syst)^{+0.0}_{-0.5}(bkg))\times10^{-4}$ assuming that the signal is due to $b \to sg^*$ transitions.
We report the results of a search for T, CP and CPT violation in B0-B0bar mixing using an inclusive dilepton sample collected by the BaBar experiment at the PEP-II B Factory. Using a sample of 232 million BBbar pairs, with a simultaneous likelihood fit of the same-sign and opposite-sign dileptons, we measure the T and CP violation parameter |q/p|-1 = (-0.8 +/- 2.7(stat.) +/- 1.9(syst.))e-03, and the CPT and CP parameters Im(z) = (-13.9 +/- 7.3 (stat.) +/- 3.2(syst.))e-03 and DeltaGamma x Re(z) = (-7.1 +/- 3.9(stat.) +/- 2.0(syst.))e-03 ps^{-1}. The statistical correlation between the measureme…
We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 million BBbar events recorded with the BABAR detector at the Y(4S) resonance. 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. The number of signal events is extracted from the hadronic mass distribution and is used to determine the ratio of branching fractions BR(B->Xulnu)/BR(B->Xlnu) = (2.06 +/-0.25(stat) +/-0.23(syst) +/-0.36(theo)) x 10^{-2}. Using the measured branching fraction for inclus…
We present a preliminary determination of the inclusive branching fraction for the rare radiative penguin transition B -> X_{s} gamma. The measurement is based on a data sample of 60 million BB pairs collected between 1999 and 2001 with the BaBar detector at the PEPII asymmetric-energy e+e- B Factory at SLAC. We study events containing a high-energy photon from one B (or Bbar) decay and a tagging primary lepton from the decay of the other B meson. By this means, we are able to reduce a significant component of the background without introduction of model dependent uncertainties in the event se…
We present measurements of partial branching fractions of $B \rightarrow K^+ X$, $B \rightarrow K^0 X$, and $B \rightarrow π^+ X$, where $X$ denotes any accessible final state above the endpoint for B decays to charmed mesons, specifically for momenta of the candidate hadron greater than 2.34 (2.36) GeV for kaons (pions) in the B rest frame. These measurements are sensitive to potential new-physics particles which could enter the $b \rightarrow s(d)$ loop transitions. The analysis is performed on a data sample consisting of $383 \times 10^6$ $B \bar{B}$ pairs collected with the BaBar detector …
BSAURUS is a software package for the inclusive reconstruction of B-hadrons in Z-decay events taken by the DELPHI detector at LEP. The BSAURUS goal is to reconstruct B-decays, by making use of as many properties of b-jets as possible, with high efficiency and good purity. This is achieved by exploiting the capabilities of the DELPHI detector to their extreme, applying wherever possible physics knowledge about B production and decays and combining different information sources with modern tools- mainly artificial neural networks. This note provides a reference of how BSAURUS outputs are formed,…
A preliminary study of time dependence of B^0-anti-B^0 oscillations using dilepton events is presented. The flavor of the B meson is determined by the charge sign of the lepton. To separate signal leptons from cascade and fake leptons we have used a method which combines several discriminating variables in a neural network. The time evolution of the oscillations is studied by reconstructing the time difference between the decays of the B mesons produced by the Y(4S) decay. With an integrated luminosity of 7.7 fb-1 collected on resonance by BABAR at the PEP-II asymmetric B Factory, we measure t…
We report the measurement of an inclusive partial branching fraction for charmless semileptonic B decay and the extraction of |V_ub|. Candidates for B -> X_u l nu are identified with a novel X_u-reconstruction method based on neutrino reconstruction via missing 4-momentum and a technique called ``simulated annealing.'' Based on 86.9/fb of data taken with the Belle detector, we obtain Br (B -> X_u l nu ; M_X<1.7 GeV/c^2, q^2>8.0 GeV^2/c^2) = (7.37 +- 0.89(stat.) +- 1.12(syst.) +- 0.55(b -> c) +- 0.24(b -> u)) x 10^(-4) and determine |V_ub| = (4.66 +- 0.28(stat.) +- 0.35(syst.) +- 0.17(b -> c) +…
We study the inclusive electron spectrum of B->X_u e nu decays near the kinematic limit for B->X_c e nu transitions using a sample of 88 million Upsilon(4S) decays recorded by the BABAR detector at the PEP II e+e- storage rings. For the electron momentum interval of 2.0 - 2.6 GeV/c the partial branching fraction is measured to be DeltaB(B->X_u e nu) = (0.480 +/- 0.029_{stat} +/- 0.053_{syst})x10^{-3}. Combining this result on with measurements of the inclusive photon spectrum in B->X_s gamma transition we find |V_ub|=(3.94 +/- 0.25_{exp} +/- 0.37_{f_u} +/- 0.19_{theory})x10^{-3}, where the fir…
We present a determination of the CKM matrix element |Vub| based on the analysis of semileptonic B decays from a sample of 88 million Upsilon(4S) decays collected with the BABAR detector at the PEP-II e+e- storage ring. Charmless semileptonic B decays are selected using measurements of the electron energy and the invariant mass squared of the electron-neutrino pair. We obtain |Vub| = (3.95 +/- 0.26 ^{+0.58}_{-0.42} +/- 0.25) x 10^{-3}, where the errors represent experimental uncertainties, heavy quark parameter uncertainties, and theoretical uncertainties, respectively.
CP violation in B0B0bar mixing is characterized by the value of the parameter |q/p| being different from 1, and the Standard Model predicts this difference to be smaller than 10^{-3}. We present a measurement of this parameter using a partial reconstruction of one of the B mesons in the semileptonic channel D*- l+ nu_l, where only the hard lepton and the soft pion from the D*- --> D0bar pi- decay are reconstructed. The flavor of the other B is determined by means of lepton tagging. The determination of |q/p| is then performed with a fit to the proper time difference of the two B decays. We use…
We present an analysis of the composition of inclusive semileptonic B meson decays using 9.4/fb of e+ e- data taken with the CLEO detector at the Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics, the neutrino 4-vector is inferred using the hermeticity of the detector. We perform a maximum likelihood fit over the full three-dimensional differential decay distribution for the fractional contributions from the B -> Xc l nu processes with Xc = D, D*, D**, and non-resonant Xc, and the process B -> Xu l nu. From the fit results we extract |V_ub|= (4.05 +- 0.18 +- 0.58 +-…
We report on the inclusive branching fractions of $B^-$ and of ${\bar B}^0$ mesons decaying to ${D^0 X}$, ${{\bar D}^0 X}$, ${D^+ X}$, ${D^- X}$, ${D_s^+ X}$, ${D_s^- X}$, ${Λ_c^+ X}$, ${{\bar Λ}_c^- X}$, based on a sample of 88.9 million $B \bar B$ events recorded with the $BABAR$ detector at the $Υ(4S)$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charmed particle in the rest of the event. We measure the number of charmed and of anti-charmed particles per $B$ decay and derive the total charm yield per $B^-$ decay, $n_c^- = 1.313 \pm 0.…
