335 research outputs found

    Reconstruction of Gravitational Lensing Using WMAP 7-Year Data

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    Gravitational lensing by large scale structure introduces non-Gaussianity into the Cosmic Microwave Background and imprints a new observable, which can be used as a cosmological probe. We apply a four-point estimator to the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year coadded temperature maps alone to reconstruct the gravitational lensing signal. The Gaussian bias is simulated and subtracted, and the higher order bias is investigated. We measure a gravitational lensing signal with a statistical amplitude of C\mathcal {C} = 1.27±0.981.27\pm 0.98 using all the correlations of the W- and V-band Differencing Assemblies (DAs). We therefore conclude that WMAP 7-year data alone, can not detect lensing.Comment: 10 pages, 10 figure

    A New Method for Selecting Exclusive Semileptonic Charmless B-Decays at e+e−e^+ e^- Colliders at the Υ(4S)\Upsilon(4S)

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    We introduce a new method for selecting exclusive semileptonic charmless B-decays in the presence of a large background. The method can be applied to charged and neutral B-mesons decaying into any exclusive neutral or charged hadronic final state. The method is designed for high luminosity \eplemi colliders operating at the Υ(4S)\Upsilon(4S). It employs an improved partial reconstruction technique for \Dstar-mesons and a novel 0-C event fit to both B-meson's decay products resulting in the kinematics of all particles (including neutrinos) in the event. The charged lepton energies are accessible from 1.0 \GeV to the kinematic limit.Comment: 10 pages with 7 figures in subdirectory fi

    Measuring gravitational lensing of the cosmic microwave background using cross correlation with large scale structure

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    We cross correlate the gravitational lensing map extracted from cosmic microwave background measurements by the Wilkinson Microwave Anisotropy Probe (WMAP) with the radio galaxy distribution from the NRAO VLA Sky Survey (NVSS) by using a quadratic estimator technique. We use the full covariance matrix to filter the data, and calculate the cross-power spectra for the lensing-galaxy correlation. We explore the impact of changing the values of cosmological parameters on the lensing reconstruction, and obtain statistical detection significances at >3σ>3\sigma. The results of all cross correlations pass the curl null test as well as a complementary diagnostic test using the NVSS data in equatorial coordinates. We forecast the potential for Planck and NVSS to constrain the lensing-galaxy cross correlation as well as the galaxy bias. The lensing-galaxy cross-power spectra are found to be Gaussian distributed.Comment: 16 pages, 10 figure

    Observation of New States Decaying into Λc+π−π+\Lambda_{c}^{+}\pi^{-}\pi^{+}

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    Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invariant mass of 596 +- 1 +- 2 MeV above the Lambda_c^+ mass. These results are preliminary.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    First Observation of the Σc∗+\Sigma_{c}^{*+} Baryon and a New Measurement of the Σc+\Sigma_{c}^{+} Mass

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    Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Σc∗+\Sigma_c^{*+} charmed baryon, and an updated measurement of the mass of the Σc+\Sigma_c^+ baryon. We find M(Σc∗+)−M(Λc+)M(\Sigma_c^{*+})-M(\Lambda_c^+)= 231.0 +- 1.1 +- 2.0 MeV, and M(Σc+)−M(Λc+)M(\Sigma_c^{+})-M(\Lambda_c^+)= 166.4 +- 0.2 +- 0.3 MeV, where the errors are statistical and systematic respectively.Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    A Measurement of the Decay Asymmetry Parameters in \Xi_{c}^{0}\to \X^{-}\pi^{+}

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    Using the CLEO II detector at the Cornell Electron Storage Ring we have measured the Ξc0\Xi_c^{0} decay asymmetry parameter in the decay Ξc0→Ξ−π+\Xi_c^{0} \to \Xi^{-} \pi^+. We find αΞc0αΞ=0.26±0.18(stat)−0.04+0.05(syst)\alpha_{\Xi_c^{0}} \alpha_{\Xi} = 0.26 \pm 0.18{(stat)}^{+0.05}_{-0.04}{(syst)}, using the world average value of αΞ=−0.456±0.014\alpha_{\Xi} = -0.456 \pm 0.014 we obtain αΞc0=−0.56±0.39(stat)−0.09+0.10(syst)\alpha_{\Xi_c^{0}} = -0.56 \pm 0.39{(stat)}^{+0.10}_{-0.09}{(syst)}. The physically allowed range of a decay asymmetry parameter is −1<α<+1-1<\alpha<+1. Our result prefers a negative value: αΞc0\alpha_{\Xi_c^{0}} is <0.1<0.1 at the 90% CL. The central value occupies the middle of the theoretically expected range but is not yet precise enough to choose between models.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Investigation of Semileptonic BB Meson Decay to P-Wave Charm Mesons

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    We have studied semileptonic BB meson decays with a P-wave charm meson in the final state using 3.29 x 10^6 B\bar{B} events collected by the CLEO~II detector at the Cornell Electron-positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction: Br(B^- -> D_1^0 l^- \bar{\nu}) x Br(D_1^0 -> D^{*+}\pi^-) = (0.373 \pm 0.085 \pm 0.052 \pm 0.024)% and an upper limit for Br(B^- -> D_2^{*0} l^- \bar{\nu}) x Br(D_2^{*0} -> D^{*+}\pi^-) < 0.16%$ (90% C.L.). These results indicate that at least 20% of the total B^- semileptonic rate is unaccounted for by the observed exclusive decays, B^- -> D^0 l^- \bar{\nu}, B^- -> D^{*0} l^- \bar{\nu}, B^- -> D_1^0 l^- \bar{\nu}, and B^- -> D_2^{*0} l^- \bar{\nu}.Comment: 10 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    First Observation of Υ(1S)→γππ\Upsilon(1S)\to \gamma\pi\pi

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    We report on a study of exclusive radiative decays of the Upsilon(1S) resonance collected with the CLEO-II detector operating at CESR. We present the first observation of the radiative decays Upsilon(1S)->gamma pi+pi- and Upsilon(1S)->gamma pi0pi0. For the dipion mass regime m(pipi)>1.0 GeV, we obtain Br(Upsilon(1S)->gamma pi+pi-=(6.3+/-1.2+/-1.3) x 10^(-5), and Br(Upsilon(1S)->gamma pi0pi0=(1.7+/-0.6+/-0.3) x 10^(-5). The observed gamma pipi events are consistent with the hypothesis Upsilon(1S)->gamma f2(1270).Comment: 9 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of Br(D0→K−π+)Br(D^{0}\to K^{-}\pi^{+}) using Partila Reconstruction of Bˉ→D∗+Xℓ−νˉ\bar{B}\to D^{*+}X\ell^{-}\bar{\nu}

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    We present a measurement of the absolute branching fraction for D0−>K−pi+D^0 -> K^- pi^+ using the reconstruction of the decay chain Bbar−>D∗+Xl−nubarBbar -> D^{*+} X l^- nubar , D∗+−>D0pi+D^{*+} -> D^0 pi^+ where only the lepton and the low-momentum pion from the D∗+D^{*+} are detected. With data collected by the CLEO II detector at the Cornell Electron Storage Ring, we have determined Br(D0−>K−pi+)=[3.81+−0.15(stat.)+−0.16(syst.)]Br(D^0 -> K^- pi^+)= [3.81 +- 0.15(stat.) +- 0.16(syst.)]%.Comment: 10 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Observation of Two Narrow States Decaying into Ξc+γ\Xi_{c}^{+}\gamma and Ξc0γ\Xi_{c}^{0}\gamma

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    We report the first observation of two narrow charmed strange baryons decaying to Ξc+γ\Xi_c^+\gamma and Ξc0γ\Xi_c^0\gamma, respectively, using data from the CLEO II detector at CESR. We interpret the observed signals as the Ξc+′(csu)\Xi_c^{+\prime}(c{su}) and Ξc0′(csd)\Xi_c^{0\prime}(c{sd}), the symmetric partners of the well-established antisymmetric Ξc+(c[su])\Xi_c^+(c[su]) and Ξc0(c[sd])\Xi_c^0(c[sd]). The mass differences M(Ξc+′)−M(Ξc+)M(\Xi_c^{+\prime})-M(\Xi_c^+) and M(Ξc0′)−M(Ξc0)M(\Xi_c^{0\prime})-M(\Xi_c^0) are measured to be 107.8±1.7±2.5107.8\pm 1.7\pm 2.5 and 107.0±1.4±2.5MeV/c2107.0\pm 1.4\pm 2.5 MeV/c^2, respectively.Comment: 11 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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