arXiv subjects

The BABAR Collaboration

Publications and source records attributed to The BABAR Collaboration.

At least 451 records · Page 25Linked to original sources

arXiv2004

Limit on the B0->rho0rho0 Branching Fraction and Implications for the CKM Angle alpha

We search for the decay B0 -> rho0 rho0 in a data sample of about 227 million Upsilon(4S)-> BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find no significant signal and set an upper limit of 1.1*10^-6 at 90% CL on the branching fraction. As a result, the uncertainty due to penguin contributions on the CKM unitarity angle alpha measured in B -> rho rho decays is 11 degrees at 68% CL.

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arXiv2004

Branching Fractions and CP Asymmetries in B0 -> pi0pi0, B+ -> pi+pi0 and B+ -> K+pi0 Decays and Isospin Analysis of the B -> pipi System

Based on a sample of 227 million BBbar pairs collected by the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the branching fraction B(B0 -> pi0pi0) = (1.17 +- 0.32 +- 0.10) x 1e-6, and the asymmetry C(pi0pi0) = -0.12 +- 0.56 +- 0.06. The B0 -> pi0pi0 signal has a significance of 5.0 sigma. We also measure B(B+ -> pi+pi0) = (5.8 +- 0.6 +- 0.4) x 1e-6, B(B+ -> K+pi0) = (12.0 +- 0.7 +- 0.6) x 1e-6, and the charge asymmetries A(pi+pi0) = -0.01 +- 0.10 +- 0.02 and A(K+pi0) = 0.06 +- 0.06 +- 0.01. Using isospin relations we find an upper bound on the angle difference |alpha - alpha(eff)| of 35 degrees at the 90% C.L.

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arXiv2004

Measurements of B meson decays to omega K* and omega rho

We describe searches for B meson decays to the charmless vector-vector final states omega K* and omega rho in 89 million B-Bbar pairs produced in e+e- annihilation at sqrt(s)=10.58 GeV. We measure the following branching fractions in units of 10^{-6}: BF(B0 -> omega K*0) = 3.4 +1.8 -1.6 +/- 0.4 (<6.0), BF(B+ -> omega K*+) = 3.5 +2.5 -2.0 +/- 0.7 (<7.4), BF(B0 -> omega rho0) = 0.6 +1.3 -1.1 +/- 0.4 (<3.3), and BF(B+ -> omega rho+) = 12.6 +3.7 -3.3 +/- 1.6. The first error quoted is statistical, the second systematic, and the upper limits are defined at 90% confidence level. For B+ -> omega rho+ we also measure the longitudinal spin alignment fraction f_L = 0.88 +0.12 -0.15 +/- 0.03 and charge asymmetry Ach = (5 +/- 26 +/- 2)%.

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arXiv2004

Ambiguity-Free Measurement of cos2beta: Time-Integrated and Time-Dependent Angular Analyses of B->J/Psi K pi

We present results on $B\to J/ψ\xspace Kπ$ decays using $e^+e^-$ annihilation data collected with the BABAR detector at the $Υ(4S)$ resonance. The detector is located at the PEP-II asymmetric-energy storage ring facility at the Stanford Linear Accelerator Center. Using approximately 88 million $B\bar{B}$ pairs, we measure the decay amplitudes for the flavor eigenmodes and observe strong-phase differences indicative of final-state interactions with a significance of 7.6 standard deviations. We use the interference between the $Kπ$ $S$-wave and $P$-wave amplitudes in the region of the $K^*(892)$ to resolve the ambiguity in the determination of these strong phases. We then perform an ambiguity-free measurement of $\cos2β$ using the angular and time-dependent asymmetry in $B\to J/ψ\xspace K^{*0}(K_S^0π^0$) dec With $\sin 2 β$ fixed at its measured value and $\cos 2 β$ treated as an in we find $\cos 2β=2.72_{-0.79}^{+0.50}\mathrm{(stat)} \pm 0.27\mathrm{(syst)}$, de sign of $\cos 2β$ to be positive at 86% CL.

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arXiv2004

Search for Strange Pentaquark Production in e+e- Annihilations at sqrt(s)=10.58 GeV and in Upsilon(4S) Decays

We present an inclusive search for strange pentaquark production in e+e- interactions at a center-of-mass energy of 10.58 GeV using 123 fb-1 of data collected with the BaBar detector. We look for the states that have been reported previously: the Theta+(1540), interpreted as a ududsbar state; and the Xi--(1860) and Xi0(1860), candidate dsdsubar and uss(uubar+ddbar) states, respectively. In addition we search for other members of the antidecuplet and corresponding octet to which these states are thought to belong. We find no evidence for the production of such states and set preliminary limits on their production cross sections as functions of c.m. momentum. The corresponding limits on the Theta+(1540) and Xi--(1860) rates per e+e- to qqbar event are well below the rates measured for ordinary baryons of similar mass.

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arXiv2004

Search for B-Meson Decays to Two-Body Final States with a0(980) Mesons

We present a search for B decays to charmless final states involving charged or neutral a0 mesons. The data sample corresponds to 89 million BBbar pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC. We find no significant signals and determine the following 90% C.L. upper limits: BR(B0 -> a0-pi+) < 5.1x10{-6}, BR(B0 -> a0-K+) < 2.1x10{-6}, BR(B- -> a0-K0bar) < 3.9x10{-6}, BR(B+ -> a00pi+) < 5.8x10{-6}, BR(B+ -> a00K+) < 2.5x10{-6}, and BR(B0 -> a00K0) < 7.8x10{-6}, where in all cases BR indicates the product of branching fractions for B -> a0X and a0 -> etapi, where X indicates K or pi.

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arXiv2004

Search for Lepton-Flavor Violation in the Decay tau -> lhh

A search for the lepton-flavor-violating decay of the tau into one charged lepton and two charged hadrons has been performed using $221.4 \mathrm{fb}^{-1}$ of data collected at an $e^+e^-$ center-of-mass energy around 10.58 GeV with the BABAR detector at the PEP-II storage ring. In all 14 decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range $(0.7-4.8)\times 10^{-7}$ at 90% confidence level. All results are preliminary.

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arXiv2004

Measurement of Time-Dependent CP Asymmetry in $B^0\to D^{(*)\pm}π^\mp$ Decays and Constraints on $sin(2β+γ)$

We present a measurement of time-dependent CP-violating asymmetries in fully reconstructed $B^0->D^{(*)\pm}π^\mp$ decays in a data sample of approximately 88 million $Y(4S)\to B\bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC. We interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle, and find $|sin(2β+γ)|>0.69$ at 68% confidence level. We exclude the hypothesis of no CP-violation ($sin(2β+γ) = 0$) at 83% confidence level.

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arXiv2004

Measurement of Time-Dependent CP Asymmetry in B0->D^(*)+-pi-+ Decays and Constraints on |sin(2beta+gamma)|

We present preliminary results of a time-dependent measurement of CP-violating asymmetry in fully reconstructed B0->D^(*)+-pi-+ decays in a data sample of approximately 88 million Y(4S)->BB decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC. We interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle, and set the bound |sin(2beta+gamma)|>0.69 at 68% confidence level. We exclude sin(2beta+gamma) = 0 at 83% confidence level.

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arXiv2004

Search for the D_(sJ)(2632)^+ at BaBar

We have performed a search for the $D^*_{sJ}(2632)^+$ state recently reported by the SELEX Collaboration at FNAL. This preliminary analysis makes use of an integrated luminosity of 125 ${\rm fb}^{-1}$ collected by the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider. The resulting $D_s η$ and $D^0 K^+$ mass spectra show no evidence for the $D^*_{sJ}(2632)^+$ state. In addition, no signal is observed in the $D^{*+} K_S$ mass spectrum.

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arXiv2004

Search for decays of B0 mesons into pairs of charged leptons: B0->e+e-, B0->mu+mu-, B0->e+-mu-+

We present a search for the decays B0->e+e-, B0->mu+mu-, and B0->e+- mu-+ in data collected at the Y(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(B0->e+e-)< 6.1 x 10^-8, B(B0->mu+mu-) < 8.3 x 10^-8, and B(B0->e+-mu-+) < 18 x 10^-8.

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arXiv2004

Measurement of the Branching Ratio Gamma(D_s^* -> D_s pi0)/Gamma(D_s^* --> D_s gamma)

The (Delta I = 1) decay D_s^* --> Ds pi0 and (ΔI = 0) decay D_s^* --> Ds gamma have been reconstructed using 90.4 fb^-1 of data recorded by the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider. The relative branching fraction of isospin violating decay to isospin conserving decay has been measured. Our preliminary result for this ratio is Gamma(D_s^* -> D_s pi0)/Gamma(D_s^* --> D_s gamma) = 0.0621 +/- 0.0049 (stat) +/- 0.0063 (syst). In addition we reconstruct the decays D^* --> D0 pi0 and D^* --> D0 gamma for completeness and measure a preliminary relative branching fraction to be Gamma(D^* --> D0 pi0)/Gamma(D&* --> D0 gamma) = = 1.740 +/- 0.020 (stat) +/- 0.125 (syst). Both measurements represent significant improvements over present world averages.

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arXiv2004

Study of B0 -> pi0pi0, B+ -> pi+pi0 and B+ -> K+pi0 decays

We present updated measurements of the branching fractions for the modes B0->pi0pi0, B+ -> pi+pi0, and B+ -> K+pi0. We also measure the time-integrated asymmetry C_pi0pi0 and the charge asymmetries A_CP(pi+pi0) and A_CP(K+pi0). Based on a sample of approximately 227 million BBar pairs collected by the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure BR(B0 -> pi0pi0) = (1.17 +/- 0.32 +/- 0.10)*10^{-6}, C_pi0pi0 = -0.12 +/- 0.56 +/- 0.06, where the first errors are statistical and the second are systematic. The B0 -> pi0pi0 signal has a significance of 4.9sigma including systematic uncertainties. We also measure BR(B+ -> pi+pi0) = (5.8 +/- 0.6 +/- 0.4)*10^{-6}, A_CP(pi+pi0) = -0.01 +/- 0.10 +/- 0.02, BR(B+ -> K+pi0) = (12.0 +/- 0.7 +/- 0.6)*10^{-6}, A_CP(K+pi0) = 0.06 +/- 0.06 +/- 0.01 . Using related BaBar measurements and isospin relations we find an upper bound on the angle difference |delta| = |alpha - alpha_eff| of 35 degrees at the 90% C.L.

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arXiv2004

Search for an X(3872) charged partner in the decay mode X- ->J/psi pi- pi0 in the B meson decays B0 -> X- K+ and B- -> X- Ks

We report on the search for a charged partner of the X(3872) in the decay $B \to X^\pm K$, $X^\pm \to J/ψπ^\pm π^0$, using 213 million $B\bar B$ events collected at the $Υ(4S)$ resonance with the BaBar detector at the PEP-II $e^+ e^-$ asymmetric-energy storage ring. The resulting product branching fraction upper limits are $BR (\bar{B}^0/B^0 \to X^\pm K^\mp$, $X^\pm \to J/ψπ^\pm π^0)$ $< 5.8 \times 10^{-6}$ and $BR (B^\pm \to X^\pm K^0_S$, $X^\pm \to J/ψπ^\pm π^0)$ $< 11 \times 10^{-6}$ at the 90% confidence level. All results are preliminary.

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arXiv2004

Measurement of the B0 --> K0S K0S K0S Branching Fraction

We report a preliminary measurement of the branching fraction for the decay $B^0 \to K^0_sK^0_sK^0_s ,$ where the $K^0_s$ mesons are reconstructed through the decay $K^0_s\toπ^+ π^- .$ The measurement was performed on a sample of $211\times 10^6$ $B\bar{B}$ pairs collected by the BABAR detector running on the $Υ(4S)$ resonance at the PEP-II storage ring. The branching fraction is measured to be $${\cal B}(B^0 \to K^0_sK^0_sK^0_s)= (6.5\pm 0.8\pm 0.8) \times 10^{-6},$$ where the errors are statistical and systematic, respectively.

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arXiv2004

Measurement of the D_(sJ)(2317) and D_(sJ)(2460) Properties in e^+ e^- --> c c-bar Production

The properties of the $\DsTT$ and $\DsFE$ mesons are studied using 125 ${\rm fb}^{-1}$ of $e^+e^- \to c \bar{c}$ data collected by the BaBar experiment. Preliminary mass estimates of $[2318.9\pm 0.3 ({\rm stat.}) \pm 0.9 ({\rm syst.})]$ \mevcc and $[2459.4 \pm 0.3 ({\rm stat.}) \pm 1.0 ({\rm syst.})]$ \mevcc are obtained. Searches are performed for the decay to the $D_s^+$ meson along with one or more $\piz$, $π^+$, or $γ$ particles. A search is also performed for neutral and doubly-charged partners.

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arXiv2004

Measurements of CP Asymmetries in the Decay B --> Phi K

We present a preliminary measurement of the time-dependent CP asymmetry for the neutral $B$-meson decay $B^0\toϕK^0$. We use a sample of approximately 227 million $B$-meson pairs recorded at the $Υ(4S)$ resonance with the BaBar detector at the PeP-II $B$-meson Factory at SLAC. We reconstruct the $CP$ eigenstates $ϕK^0_S$ and $ϕK^0_L$ where $ϕ\to K^+K^-$, $K^0_S\toπ^+π^-$, and $K^0_L$ is observed via its hadronic interactions. The other $B$ meson in the event is tagged as either a $B^0$ or $\bar{B}^0$ from its decay products. The values of the CP-violation parameters derived from the combined $ϕK^0$ dataset are $S_{ϕK} = +0.50\pm 0.25 ({\small stat})^{+0.07}_{-0.04} ({\small syst})$ and $C_{ϕK} = 0.00\pm 0.23 ({\small stat}) \pm 0.05 ({\small syst})$. In addition, we measure the CP -violating charge asymmetry $\mathcal{A_{CP}} (B^+\to ϕK^+) = 0.054\pm 0.056 ({\small stat}) \pm 0.012 ({\small syst})$. All results are preliminary.

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arXiv2004

Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR

The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.

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