arXiv subjects

B. Aubert

Publications and source records attributed to B. Aubert.

At least 451 records · Page 25Linked to original sources

arXiv2004

Study of B -> DsJ()+ Dbar() Decays

We report a study of DsJ*(2317)+ and DsJ(2460)+ meson production in B decays. We observe the decays B+ -> DsJ(*)+ Dbar(*)0 and B0 -> DsJ(*)+ D(*)- with the subsequent decays DsJ*(2317)+ -> Ds+ pi0, DsJ(2460)+ -> Ds+ gamma, and DsJ(2460)+ -> Ds*+ pi0. Based on a data sample of 122.1 million BBbar pairs collected with the BaBar detector at the PEP-II B factory, we obtain branching fractions for these modes, including the previously unseen decays B -> DsJ(*)+ D*. In addition, we perform an angular analysis of DsJ(2460)+ -> Ds+ gamma decays to test the different DsJ(2460)+ spin hypotheses.

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arXiv2004

Study of the tau- -> 3h- 2h+ nu-tau Decay

A preliminary measurement of the branching fraction of the tau- -> 3h-2h+nu decay (h= pi, K$) with the BaBar detector is found to be {8.52 +/- 0.09 +/- 0.40} x 10E-4, where the first error is statistical and the second is systematic. The data show evidence that the rho resonance plays a strong role in the decay of the tau lepton to five charged hadrons.

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arXiv2004

A study of B0bar --> D()0 K()bar decays

We present a study of the decays B0bar --> D(*)0 K(*)0bar using a sample of 124 million Upsilon(4S) --> B0bar B0 decays collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We report evidence for the decay of B0 and B0bar mesons to the D*0 K_S final state with an average branching fraction BF(B --> D*0 K0bar) = (4.5 +/- 1.9 +/- 0.5) x 10^-5. Similarly, we measure BF(B --> D0 K0bar) = (6.2 +/- 1.2 +/- 0.4) x 10^-5 for the D0 K_S final state. We also measure BF(B0bar --> D0 K*0bar) = (6.2 +/- 1.4 +/- 0.6) x 10^-5 and set a 90% C.L. upper limit BF(B0bar --> D0bar K*0bar) < 4.1 x 10^-5. All results presented in this paper are preliminary.

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arXiv2004

Measurement of the ratio of branching fractions of Xic0 decays to Xi- pi+ and to Omega- K+

We have analyzed 116 fb^-1 of data collected by the BABAR detector for Xic0 production. In this paper we describe the observation of Xic0 production from ccbar continuum and from B decays, with the Xic0 decaying into (Xi- pi+) and (Omega- K+) modes. The ratio of the branching fractions of the Xic0 decays into these two final states measured in the ccbar continuum is: B(Xic0 -> Omega- K+) / B(Xic0 -> Xi- pi+) = 0.296 +- 0.018 (stat.) +- 0.030 (sys.). All results in this note are preliminary.

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arXiv2004

Searches for Charmless Decays B0 -> eta omega, B0 -> eta K0, B+ -> eta rho+, and B+ -> eta' pi+

We present measurements of branching fractions for four previously unobserved B-meson decays with an eta or eta' meson in the final state. The data sample corresponds to 182 million B-Bbar pairs produced from e+e- annihilation at the Upsilon(4S) resonance. We measure the following branching fractions in units of 10^-6: BF(B0 -> eta omega) = 1.2 +/- 0.6 +/- 0.2 (<2.3 at 90% C.L.), BF(B0 -> eta K0) = 2.5 +/-0.8 +/- 0.1, BF(B+ -> eta rho+) = 8.6 +/- 2.2 +/- 1.1, and BF(B+ -> eta' pi+) = 4.2 +/- 1.0 +/- 0.5, where the first error quoted is statistical and the second systematic. The charge asymmetries are A_ch(B+ -> eta rho+) = (7 +/- 19 +/- 2)% and A_ch(B+ -> eta' pi+) = (24 +/- 19 +/- 1)%. All results are preliminary.

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arXiv2004

Measurement of the B0bar Lifetime and of the B0-B0bar Oscillation Frequency Using Partially Reconstructed B0bar -> D*+ l- anti-nu(l) Decays

We present a simultaneous measurement of the B0bar lifetime tau(B0) and mixing parameter $Delta m_d$. We use a sample of about 50000 B0bar -> D*+ l- anti-nu(l) partially reconstructed decays identified with the BABAR detector at the PEP-II storage ring at SLAC, where the flavor of the other B meson is determined from the charge of another high momentum lepton in the same event. The preliminary results are: tau(B0) = (1.501+/-0.008(stat.) +/- 0.030 (syst.)) ps, $Delta m_d$ = (0.523+/-0.004(stat.) +/- 0.007 (syst.)) ps^{-1}.

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arXiv2004

Partial Reconstruction of $B^0\to D_s^{\ast+} D^{\ast-}$ Decays and Measurement of the $D_s^+\toϕπ^+$ Branching Fraction

We present preliminary results on the branching fractions $BF(B^0\to D_s^{\ast+} D^{\ast-})$ and $BF(D_s^+\toϕπ^+)$, based on a data sample of approximately $124\times10^6$ \BB events collected by the \babar detector at the PEP-II $e^+ e^-$ \B--factory. $BF(B^0\to D_s^{\ast+} D^{\ast-})$ is measured selecting neutral \B meson decays to the final state $D_s^{\ast+} D^{\ast-}$ with partial reconstruction of the $D_s^{\ast+}$, in which only the $D^{\ast-}$ and the soft photons from the decay $D_s^{\ast+} \to D_s^+ γ$ are reconstructed. The branching fraction product $BF(B^0\to D_s^{\ast+} D^{\ast-}) \cdot BF(D_s^+\toϕπ^+)$ is measured via a complete reconstruction of the whole decay chain. Comparing these two measurements provides a model-independent determination of the $BF(D_s^+\toϕπ^+)$ branching fraction. We obtain the following preliminary results: $BF(B^0\to D_s^{\ast+} D^{\ast-}) = (1.85 \pm 0.09 \pm 0.16)%$, $BF(D_s^+\toϕπ^+) = (4.71 \pm 0.47 \pm 0.35)%$ where the first error in each measurement is statistical, the second systematic.

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arXiv2004

Determination of |Vub| in inclusive semileptonic B meson decays

We present a preliminary 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 e+e- storage ring. Charmless semileptonic B decays are selected using the electron energy E_e and the invariant mass q^2 of the electron-neutrino pair. The neutrino momentum is inferred from a measurement of the visible energy and momentum in the detector and knowledge of the e+e- beam momenta. The partial branching fraction is determined in a region of the q^2-E_e plane where semileptonic B decays to charm are highly suppressed. The total charmless semileptonic branching fraction is extracted using a theoretical calculation based on the heavy quark expansion. Preliminary results yield |Vub| = (4.57 +/- 0.21 +/- 0.25 +/- 0.34 +0.59/-0.29 +/- 0.22) x 10^{-3} where the uncertainties are from statistics (data and MC), detector modeling, background modeling, the shape function, and the heavy quark operator product expansion, respectively.

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arXiv2004

Measurement of the B -> Xs l+ l- branching fraction with a sum over exclusive modes

We measure the branching fraction for the flavor-changing neutral-current process B -> Xs l+ l- with a sample of 89 x 10^6 Upsilon(4S) -> BBbar events recorded with the BaBar detector at the PEP-II e+e- storage ring. The final state is reconstructed from e+e- or mu+mu- pairs and a hadronic system consisting of one K or K0s and up to two pions, with at most one pi0. We observe a signal of 40 +/- 10(stat) +/- 2(syst) events and extract the inclusive branching fraction B(B -> Xs l+ l-) = (5.6 +/- 1.5(stat) +/- 0.6(exp syst) +/- 1.1(model syst)) x 10^-6 for mll > 0.2 GeV/c^2.

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arXiv2004

A Search for the Rare Decay B0 --> D_S+ rho-

We report on a search for the decay B0 --> D_S+ rho- in a sample of 90 million Y(4S) decays into B meson pairs collected between 1999 and 2001 with the BaBar detector at the PEP-II asymmetric-energy e+e- collider. No significant excess of signal events above the expected background is observed. We set a 90% C.L. limit on the branching fraction Br(B0 --> D_S+ rho-)< 1.9*10^{-5}. Assuming a flavor SU(3) symmetry relation between the decays B0 --> D_S+ rho- and B0 --> D+ rho-, we set a limit on the ratio of CKM-suppressed to CKM-favored amplitudes r(D rho)<9.5*10^{-3} at 90% C.L. All results are preliminary.

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arXiv2004

Amplitude Analysis of B -> pi pi pi and B -> K pi pi

We present preliminary results of a maximum-likelihood Dalitz-plot analysis of the charmless hadronic B decays to the final states pi pi pi and K pi pi from data corresponding to an integrated on-resonance luminosity of 166 fb^-1 recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy B Factory. We measure the total branching fractions B(B -> pi pi pi) = (16.2 +- 2.1 +- 1.3) x 10^-6 and B(B -> K pi pi) = (61.4 +- 2.4 +- 4.5) x 10^-6, and provide fit fractions and phases for intermediate resonance states.

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arXiv2004

Search for B --> chi_c K(*) decays

We report on the search for the factorization suppressed decays B -> chi_c0 K(*) and B -> chi_c2 K(*), with chi_c0 and chi_c2 decaying into J/psi gamma. We use a sample of 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. No significant signal is found and upper bounds for the branching fractions are obtained. All results are preliminary.

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arXiv2004

Measurement of the Branching Fractions for the Decays B0->D^{-} ppbar pi^+, B0->D^-ppbar pi^+, B0->D^{0} ppbar and B0->D^0 ppbar

The $B^0$ meson decay modes $B^0 \to D^{*-} p {\bar p} π^+$, $D^{-} p {\bar p} π^+$, ${\bar D}^{*0} p {\bar p}$, and ${\bar D}^{0} p {\bar p}$ are studied in a sample of $124\times 10^{6}$ $B{\bar B}$ pairs collected with the $BaBar$ detector at the PEP-II collider. The decay of $B^0 \to D^{-} p {\bar p} π^+$ is observed for the first time, with a measured branching fraction ${\cal B}(B^0 \to D^{-} p {\bar p} π^+)=(3.80\pm 0.35\pm 0.46)\times 10^{-4}$. The following branching fractions are also determined: ${\cal B}(B^0 \to D^{*-} p {\bar p} π^+)= (5.61\pm 0.59\pm 0.73)\times 10^{-4}$, ${\cal B}(B^0 \to {\bar D}^{*0} p {\bar p})= (0.67\pm 0.21\pm 0.09)\times 10^{-4}$, and ${\cal B}(B^0 \to {\bar D}^{0} p {\bar p})= (1.24\pm 0.14\pm 0.12)\times 10^{-4}$. In each decay mode the invariant mass spectra of the charmed mesons and the baryons are compared with a pure phase-space hypothesis in order to gain insight into the $B$ meson decay dynamics. In particular, the Dalitz plots of ${\bar D}^{*0} p$ versus ${\bar D}^{*0} {\bar p}$ for $B^0 \to {\bar D}^{*0} p {\bar p}$ and of ${\bar D}^{0} p$ versus ${\bar D}^{0} {\bar p}$ for $B^0 \to {\bar D}^{0} p {\bar p}$ are presented. All results are preliminary.

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arXiv2004

Measurement of exclusive B decays to charmonium and K or K* branching fractions with the BABAR detector

We report preliminary results on the measurement of branching fractions of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/psi, psi(2S) and chic_c1, and the light mesons are either K or K*. We use a sample of about 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.

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arXiv2004

A Search for the Theta^*++ Pentaquark in B+ -> p pbar K+

We report the results of a search for the Theta*++ pentaquark in the decay B+ -> Theta*++ pbar where Theta*++ -> pK+ using 81fb^-1 of data collected on the Upsilon(4S) resonance with the BaBar detector at PEP-II. We find an upper limit on the branching fraction of B+ -> Theta*++ pbar where Theta*++ -> pK+ to be 1.5x10^-7 for 1.43<m(Theta*++)<1.85GeV/c^2, 2.4x10^-7 for 1.85<m(Theta*++)<2.00GeV/c^2 and 3.3x10^-7 for 2.00<m(Theta*++)<2.36GeV/c^2, at 90% confidence level. All results are preliminary.

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arXiv2004

Measurement of Time-Dependent CP Asymmetries and Constraints on sin(2 beta+gamma) with Partial Reconstruction of B0->D*-+ pi+- Decays

We present a preliminary measurement of the time-dependent CP-violating asymmetry in decays of neutral B mesons to the final states D*-+ pi+- using approximately 178 million BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the amplitude of the asymmetry to be $-0.041 \pm 0.016 (stat.) \pm 0.010 (syst.)$ and determine bounds on $|\sin(2 β+ γ)|$.

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arXiv2004

Limits on the Decay-Rate Difference of Neutral-B Mesons and on CP, T, and CPT Violation in B0-antiB0 Oscillations

Using events in which one of two neutral-B mesons from the decay of an Y(4S) resonance is fully reconstructed, we set limits on the difference between the decay rates of the two neutral-B mass eigenstates and on CP, T, and CPT violation in B0-antiB0 mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million Y(4S) --> Banti-B decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations (Deltam, DeltaGamma/Gamma), CPT and CP violation (Re Z, Im Z), and CP and T violation (Im lambdaCP, |q/p|), where lambdaCP characterizes B0 and anti-B0 decays to states of charmonium plus K0S or K0L. The results are sgn(Re lambdaCP)xDeltaGamma/Gamma = -0.008 +/- 0.037(stat) +/- 0.018(syst) [-0.084,0.068], |q/p| = 1.029 +/- 0.013(stat) +/- 0.011(syst) [ 1.001,1.057], (Re lambdaCP)/|lambdaCP|xRe z = 0.014 +/- 0.035(stat) +/- 0.034(syst) [-0.072,0.101], Im z = 0.038 +/- 0.029(stat) +/- 0.025(syst) [-0.028,0.104], The values inside square brackets indicate the 90% confidence-level intervals. The values of Im lambdaCP and Deltam are consistent with previous analyses and are used as cross-checks. These measurements are in agreement with Standard Model expectations.

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arXiv2004

Measurement of the Branching Fraction of e^+e^- --> B0B0bar at the Upsilon(4S) Resonance

We report a measurement of the branching fraction e^+e^- --> B0B0bar with a data sample of 81.7 fb^-1 collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage ring. Using partial reconstruction of the decay B0bar --> D^{*+} \ell^{-} \barν_{\ell} we obtain a preliminary result of f00 = 0.486 +- 0.010(stat.) +- 0.009(sys.). Our result does not depend on branching fractions of the B0bar and the D^{*+} decay chains, on the simulated reconstruction efficiency, on the ratio of the charged and neutral B meson lifetimes, nor on assumption of isospin symmetry. This measurement is important for normalizing many B decay branching fractions, and contributes to our understanding of isospin violation in the Upsilon(4S) system.

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