arXiv subjects

B. Aubert

Publications and source records attributed to B. Aubert.

At least 379 records · Page 21Linked to original sources

arXiv2005

Search for the Decay tau to seven pion (pizero)

A search for the decay of the tau lepton to seven charged pions and one or zero pizero mesons was performed using the BaBar detector at the PEP-II asymmetric-energy e+e- collider. The analysis uses 232.2 fb-1 of data at center-of-mass energies on or near the Y(4S) resonance. We observe 24 events with an expected background of 21.6+-1.3 events. Without evidence for a signal, we calculate an upper limit of BR(tau- --> 4pi- 3pi+ (pizero) nu_tau) < 3.0*10^-7 at 90 % confidence level. This is an improvement by nearly an order of magnitude over the previously established limit. In addition, we set upper limits for the exclusive decays tau- --> 4pi- 3pi+ nu_tau and tau- --> 4pi- 3pi+ pizero nu_tau.

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arXiv2005

Measurement of Time-Dependent CP Asymmetries in B0 -> D(*)D Decays

We present a first measurement of CP asymmetries in neutral B decays to D+D-, and updated CP asymmetry measurements in decays to D*+D- and D*-D+. We use fully-reconstructed decays collected in a data sample of (232 +- 3) x 10^6 Y(4S) -> BBbar events in the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine the time-dependent asymmetry parameters to be S_{D*+D-} = -0.54 +- 0.35 +- 0.07, C_{D*+D-} = 0.09 +- 0.25 +- 0.06, S_{D*-D+} = -0.29 +- 0.33 +- 0.07, C_{D*-D+} = 0.17 +- 0.24 +- 0.04, S_{D+D-} = -0.29 +- 0.63 +- 0.06, and C_{D+D-} = 0.11 +- 0.35 +- 0.06, where in each case the first error is statistical and the second error is systematic.

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arXiv2005

Search for the Rare Decays B+ --> D(*)+K0s

We report on the search for the rare decays $B^+ \to D^{(*)+} K^0_{s}$ in approximately 226 million $Y(\rm 4S)\to b\bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy $B$ factory at SLAC. We do not observe any significant signal and we set 90% confidence level upper limits on the branching fractions, ${\ensuremath {{\cal B}(\Bp{\to}D^{+}K^0})}$ $<0.5 \times 10^{-5}$ and ${\ensuremath {{\cal B}(\Bp{\to}D^{*+}K^0})}$ $<0.9 \times 10^{-5}$.

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arXiv2005

Measurement of the branching fraction and decay rate asymmetry of B- --> D_{pi+pi-pi0}K-

We report the observation of the decay $B^- \to D_{π^+π^-π^0} K^-$, where $D_{π^+π^-π^0}$ indicates a neutral $D$ meson detected in the final state $π^+π^-π^0$, excluding $K_S π^0$. This doubly Cabibbo-suppressed decay chain can be used to measure the CKM phase $γ$. Using about 229 million $e^+e^- \to B \bar B$ events recorded by the BaBar experiment at the PEP-II $e^+e^-$ storage ring, we measure the branching fraction ${\cal B}(B^- \to D_{π^+π^-π^0} K^-) = (5.5 \pm 1.0 {\rm(stat.)} \pm 0.7 {\rm(syst.)})\times 10^{-6}$ and the decay rate asymmetry $A = 0.02 \pm 0.16 {\rm(stat.)} \pm 0.03 {\rm(syst.)}$ for the full decay chain.

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arXiv2005

Measurement of CP Asymmetries in B0 --> Phi K0 and B0 --> K+K-K0S Decays

We measure the time-dependent CP asymmetry parameters in B0 --> K+ K- K0 based on a data sample of approximately 227 million B-meson pairs recorded at the Upsilon(4S) resonance with the BaBar detector at the PEP-II B-meson Factory at SLAC. We reconstruct two-body B0 decays to Phi(1020) K0S and Phi(1020)K0L, and the three-body decay K+ K- K0S with Phi(1020) K0S excluded. For the B0 --> Phi K0 decays, we measure sin(2 beta_{eff})(Phi K0) = +0.50 +/- 0.25(stat) +0.07/-0.04(syst). The B0 --> K+ K- K0S decays are dominated by K+ K- S-wave, as determined from an angular analysis; we measure sin(2 beta_{eff})(K+ K- K0S) = +0.55 +/- 0.22(stat) +/- 0.04(syst) +/- 0.11(CP), where the last error is due to the uncertainty in the fraction of CP-even contributions to the decay amplitude. We find no evidence for direct CP violation.

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arXiv2005

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

We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*-+ pi+-, using approximately 232 million BBbar events recorded by the BABAR experiment at the PEP2 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 parameters related to 2beta+gamma to be a_D*pi=-0.034 +- 0.014 +- 0.009 and c_l_D*pi = -0.019 +- 0.022 +- 0.013. With some theoretical assumptions, we interpret our results in term of the lower limits |\sin(2beta+gamma)|> 0.62 (0.35) at 68% (90%) confidence level.

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arXiv2005

B^0 --> K^+ π^- π^0 Dalitz Plot Analysis

We present preliminary results on the Dalitz plot analysis of $B^0 \to K^+ π^- π^0$ decays. The data sample comprises 213 million $Υ(4S) \to B {\bar B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We report measurements of the inclusive branching fraction, quasi-two-body fractions and CP-violating charge asymmetries for intermediate states including $K^*(892)^+ π^-$ and $ρ(770)^- K^+$. Observations of $B^0$ decays to the $Kπ$ $S$-wave intermediate states, $K_0^*(1430)^+ π^-$ and $K_0^*(1430)^0 π^0$, are reported. Evidence of the decay $B^0 \to K^*(892)^0 π^0$ is seen. We set upper limits at 90% confidence level on branching fractions of the nonresonant and other less significant intermediate states.

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arXiv2005

Measurement of branching fractions and charge asymmetries in B+ decays to etapi+, etaK+, etarho+ and eta'pi+, and search for B0 decays to etaK0 and etaomega

We present measurements of branching fractions and charge asymmetries for six B-meson decay modes with an eta or eta' meson in the final state. The data sample corresponds to 232 million BBbar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- B Factory at SLAC. We measure the branching fractions (in units of 10^-6): B(B->etapi+)=5.1+/-0.6+/-0.3, B(B->etaK+)=3.3+/-0.6+/-0.3, B(B->etaK0)=1.5+/-0.7+/-0.1 (<2.5 at 90% C.L.), B(B->etarho+)=8.4+/-1.9+/-1.1, B(B->etaomega)=1.0+/-0.5+/-0.2 (<1.9 at 90% C.L.), and B(B->eta'pi+)=4.0+/-0.8+/-0.4, where the first uncertainty is statistical and second systematic. We also determine the charge asymmetries for the charged modes: Ach(B->etapi+)=-0.13+/-0.12+/-0.01, Ach(B->etaK+)=-0.20+/-0.15+/-0.01, Ach(B->etarho+)=0.02+/-0.18+/-0.02, and Ach(B->eta'pi+)=0.14+/-0.16+/-0.01.

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arXiv2005

Measurement of the Ratio BR(B- --> D0 K-)/BR(B- --> D0 pi-) and of the CP Asymmetry of B- --> D*0(CP+) K- Decays

We study the decays B- --> D*0 pi- and B- --> D*0 K-, where the D*0 decays into D0 pi0, with the D0 reconstructed in the CP-even (CP+) eigenstates K- K+ and pi- pi+ and in the (non-CP) channels K- pi+, K- pi+ pi+ pi-, and K- pi+ pi0. Using a sample of about 123 million BBbar pairs, we measure the ratios of decay rates R*(non-CP)=BR(B- --> D*0(non-CP) K-)/BR(B- --> D*0(non-CP) pi-) = 0.0813+-0.0040(stat)+0.0042-0.0031}(syst), and provide the first measurements of R*(CP+)= BR(B- --> D*0(CP+) K-)/BR(B- --> D*0(CP+) pi-) = 0.086+-0.021(stat)+-0. 007(syst), and of the CP asymmetry A*(CP+) = (BR(B- --> D*0(CP+) K-) - BR(B+ --> D*0(CP+) K+))/(BR(B- --> D*0(CP+) K-) + BR(B+ --> D*0(CP+) K+)) = -0.10+-0.23(stat)+0.03-0.04(syst).

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arXiv2005

Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-$ and their resonant submodes $B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 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) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)

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arXiv2005

Measurement of Branching Fraction and CP-Violating Asymmetry for B->omegaKs

We present a preliminary measurement of the branching fraction and CP-violating parameters S and C for the decay B->omegaKs. The data sample corresponds to 232x10^6 BBbar pairs produced from e+e- annihilation at the Upsilon(4S) resonance. We measure B(omegaK0)=(5.9+/-1.0+/-0.4)x10^-6, S=0.50+0.34-0.38+/-0.02 and C=-0.56+0.29-0.27+/-0.03.

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arXiv2005

Measurement of the Branching Fraction and the CP-Violating Asymmetry for the Decay B0 --> K0S Pi0

We measure the branching fraction and the CP-violating asymmetry of $B^{0}\to K_{s}^{0}π^{0}$ decays with 227 million $Υ(4S)\to B\bar{B}$ events collected with the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider at SLAC. We obtain a branching fraction ${\cal B}(B^{0}\to K^{0}π^{0}) = (11.4 \pm 0.9 \pm 0.6) \times 10^{-6}$ and CP-violating asymmetry parameters $C_{K_{s}^{0}π^{0}} = 0.06 \pm 0.18 \pm 0.03$ and $S_{K_{s}^{0}π^{0}} = 0.35^{+0.30}_{-0.33} \pm 0.04$, where the first error is statistical and the second systematic.

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arXiv2005

Measurement of the $B^0\to D^{\ast-} D_s^{\ast+}$ and $D_s^+\toϕπ^+$ Branching Fractions

We present measurements of the branching fractions $\BR(B^0\to D^{\ast-} D_s^{\ast+})$ and $\BR(D_s^+\toϕπ^+)$, based on $123\times10^6$ Y(4S)->BBbar decays collected by the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ B factory. A partial reconstruction technique is used to measure $\BR(B^0\to D^{\ast-} D_s^{\ast+})$ and the decay chain is fully reconstructed to measure the branching fraction product $\BR(B^0\to D^{\ast-} D_s^{\ast+})\times\BR(D_s^+\toϕπ^+)$. Comparing these two measurements provides a model-independent determination of the \Dsphipi\ branching fraction. We obtain $\BR(B^0\to D^{\ast-} D_s^{\ast+}) = (1.88 \pm 0.09 \pm 0.17)%$ and $\BR(D_s^+\toϕπ^+) = (4.81 \pm 0.52 \pm 0.38)%$, where the first uncertainties are statistical and the second systematic.

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arXiv2005

The $\epem\toπ^+π^-π^+π^-$, $K^+K^-π^+π^-$, and $K^+K^- K^+K^- $ Cross Sections at Center-of-Mass Energies 0.5--4.5 \gev Measured with Initial-State Radiation

We study the process $e^+e^-\toπ^+π^-π^+π^-γ$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4π$-mass spectrum, the cross section for the process $e^+e^-\toπ^+π^-π^+π^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- π^+π^-$ and $K^+ K^- K^+ K^-$. We observe the $J/ψ$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/ψ(\toμ^+μ^-) π^+π^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/ψπ^+π^-$.

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arXiv2005

Measurements of Branching Fractions and Time-Dependent CP-Violating Asymmetries in B to eta' K Decays

We present measurements of the B -> eta' K branching fractions;for B+ -> eta' K+ we measure also the time-integrated charge asymmetry Ach, and for B0 -> eta' K0S the time dependent CP-violation parameters S and C. The data sample corresponds to 232 million B Bbar pairs produced by e+ e- annihilation at the Upsilon(4S). The results are BF(B+ -> eta' K+) = (68.9 +- 2.0 +- 3.2) * 10^-6, BF(B0 -> eta' K0) = (67.4 +- 3.3 +- 3.2) * 10^-6, Ach = 0.033 +- 0.028 +- 0.005, S=0.30 +- 0.14 +- 0.02, C=-0.21 +- 0.10 +- 0.02, where the first error is statistical and the second systematic.

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arXiv2005

Branching Fraction and CP Asymmetries of $B^0 \to K^0_S K^0_S K^0_S$

We present measurements of the branching fraction and time-dependent CP-violating asymmetries in $B^0 \to K^0_s K^0_s K^0_s$ decays based on 227 million $Υ(4S) \to B \bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We obtain a branching fraction of $(6.9^{+0.9}_{-0.8}\pm 0.6)\times 10^{-6},$ and CP asymmetries $C = -0.34^{+0.28}_{-0.25} \pm 0.05$ and $S = -0.71^{+0.38}_{-0.32} \pm 0.04,$ where the first uncertainties are statistical and the second systematic.

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arXiv2005

Search for Strange-Pentaquark Production in e+e- Annihilation at sqrt(s)=10.58 GeV

We search for strange pentaquark states that have been previously reported by other experiments -- the $Θ(1540)^+$, $Ξ_5(1860)^{--}$, and $Ξ_5(1860)^0$ -- in 123 fb$^{-1}$ of data recorded with the BaBar detector at the PEP-II $e^+e^-$ storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of $Θ(1540)^+$ and $Ξ_5(1860)^{--}$ pentaquarks produced per $e^+e^-$ annihilation event that are about eight and four times lower than the rates measured for ordinary baryons of similar mass.

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arXiv2005

A search for CP violation and a measurement of the relative branching fraction in D+ -> KKpi decays

We report on a search for the CP asymmetry in the singly Cabibbo-suppressed decays D+ -> KKpi and in the resonant decays D+ -> phipi and D+ -> KstarK based on a data sample of 79.9 fb^-1 recorded by the BABAR detector. We use the Cabibbo-favored Ds -> KKpi branching fraction as normalization in the measurements to reduce systematic uncertainties. The CP asymmetries obtained are A_{CP}(KKpi) = (1.4 +/- 1.0 (stat.) +/- 0.8 (syst.) x 10^-2, A_{CP}(phi pi) = (0.2 +/- 1.5 (stat.) +/- 0.6 (syst.) x 10^-2, and A_{CP}(Kstar K) = (0.9 +/- 1.7 (stat.) +/- 0.7 (syst.) x 10^-2. The relative branching fraction Gamma(D+ -> KKpi)/Gamma(D+ -> Kpipi) is also measured and is found to be (10.7 +/- 0.1 (stat.) +/- 0.2 (syst.) x 10^-2.

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