26 research outputs found

    After Midnight: Buried Treasure And Social Squabbles In Georgia\u27s Low Country

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    Readers who expect a Civil War story in Delirium of the Brave will be disappointed. The Civil War is just a gimmick used by William C. Harris, Jr. to set up his saga of several Savannah, Georgia, families from Civil War times till the present. It begins with a prologue in which the Grand Dra...

    Magnetic trapping of ultracold neutrons

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    Three-dimensional magnetic confinement of neutrons is reported. Neutrons are loaded into an Ioffe-type superconducting magnetic trap through inelastic scattering of cold neutrons with 4He. Scattered neutrons with sufficiently low energy and in the appropriate spin state are confined by the magnetic field until they decay. The electron resulting from neutron decay produces scintillations in the liquid helium bath that results in a pulse of extreme ultraviolet light. This light is frequency downconverted to the visible and detected. Results are presented in which 500 +/- 155 neutrons are magnetically trapped in each loading cycle, consistent with theoretical predictions. The lifetime of the observed signal, 660 s +290/-170 s, is consistent with the neutron beta-decay lifetime.Comment: 17 pages, 18 figures, accepted for publication in Physical Review

    A Measurement of the Branching Ratio of KL→e+e−γγK_L \to e^+e^-\gamma\gamma

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    We report on a study of the decay KL→e+e−γγK_L \to e^+e^-\gamma\gamma carried out as a part of the KTeV/E799 experiment at Fermilab. The 1997 data yielded a sample of 1543 events, including an expected background of 56±856 \pm 8 events. An effective form factor was determined from the observed distribution of the e+e−e^+e^- invariant mass. Using this form factor in the calculation of the detector acceptance, the branching ratio was measured to be B(KL→e+e−γγ,Eγ∗>5MeV)=(5.84±0.15 (stat)±0.32 (sys))×10−7{\mathcal B}(K_L \to e^+ e^- \gamma \gamma, E^*_\gamma > 5 {MeV}) = (5.84 \pm 0.15 {\rm ~(stat)} \pm 0.32 {\rm ~(sys)})\times 10^{-7}.Comment: 5 pages, 4 figure

    A New Measurement of the Radiative Ke3 Branching Ratio and Photon Spectrum

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    We present a preliminary report on a new measurement of the radiative neutral Ke3 branching ratio and the first study of the photon spectrum in this decay. We find BR(Ke3g, E*_g>30 GeV, Th*_eg>20 deg)/BR(Ke3) = 0.911+-0.009(stat)+0.021-0.010(syst)%. Our measurement of the spectrum is consistent with inner bremsstrahlung only as the source of photons at the 2 sigma level.Comment: 5 pages, 4 figures, proceedings paper from Meson 2000, Cracow, Poland, May 200

    Measurements of the rare decay K_{L} -> e^{+} e^{-} e^{+} e^{-}

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    We observe 441 K_{L} -> e^{+} e^{-} e^{+} e^{-} candidate events with a background of 4.2 events and measure B(K_{L} -> e^{+} e^{-} e^{+} e^{-}) = (3.72 \pm 0.18(stat) \pm 0.23(syst)) \times 10^{-8} in the KTeV/E799II experiment at Fermilab. Using the distribution of the angle between the planes of the e^{+} e^{-} pairs, we measure the CP parameters beta_{CP} = -0.23 \pm 0.09(stat) \pm 0.02(syst) and gamma_{CP} = -0.09 \pm 0.09(stat) \pm 0.02(syst). We also present the first detailed study of the e^{+} e^{-} invariant mass spectrum in this decay mode.Comment: 14 pages, 4 figure

    Search for the K(L) --> PI0 PI0 E+ E- Decay in the KTeV Experiment

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    The recent discovery of a large CP violating asymmetry in K(L) --> PI+ PI- E+ E- mode has prompted us to seach for the associated K(L) --> PI0 PI0 E+ E- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7E+11 K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the K(L) --> PI0 PI0 E+ E- branching ratio of 6.6E-09 at the 90% confidence level.Comment: To be published in Phys. Rev. Let

    Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System

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    We present a series of measurements based on K -> pi+pi- and K -> pi0pi0 decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We compare these four K -> pipi decay rates to measure the direct CP violation parameter Re(e'/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by measuring the relative phase between the CP violating and CP conserving decay amplitudes for K->pi+pi- (phi+-) and for K -> pi0pi0 (phi00). We find the difference between the relative phases to be Delta-phi = phi00 - phi+- = (+0.39 +- 0.50) degrees and the deviation of phi+- from the superweak phase to be phi+- - phi_SW =(+0.61 +- 1.19) degrees; both results are consistent with CPT symmetry. In addition, we present new measurements of the KL-KS mass difference and KS lifetime: Delta-m = (5261 +- 15) x 10^6 hbar/s and tauS = (89.65 +- 0.07) x 10^-12 s.Comment: Submitted to Phys. Rev. D, August 6, 2002; 37 pages, 32 figure

    Branching Ratio Measurement of the decay K_L -> e+ e- mu+ mu-

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    We have collected a 43 event sample of the decay KL→e+e−μ+μ−K_L\to e^+e^-\mu^+\mu^- with negligible backgrounds and measured its branching ratio to be (2.62±0.40±0.17)×10−9(2.62 \pm 0.40 \pm 0.17)\times 10^{-9} . We see no evidence for CP violation in this decay. In addition, we set the 90% confidence upper limit on the combined branching ratios for the lepton flavor violating decays KL→e±e±μ∓μ∓K_L\to e^{\pm}e^{\pm}\mu^{\mp}\mu^{\mp} at B(KL→e±e±μ∓μ∓)≤1.23×10−10{\mathcal B}(K_L\to e^{\pm}e^{\pm}\mu^{\mp}\mu^{\mp}) \leq 1.23\times10^{-10}, assuming a uniform phase space distribution

    First Measurement of Form Factors of the Decay Xi0->Sigma+ e- anti-nu/e

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    We present the first measurement of the form factor ratios g1/f1 (direct axial-vector to vector), g2/f1 (second class current) and f2/f1 (weak magnetism) for the decay Xi0 -> Sigma+ e- anti-nu/e using the KTeV (E799) beam line and detector at Fermilab. From the Sigma+ polarization measured with the decay Sigma+ -> p pi0 and the e- - anti-nu/e correlation, we measure g1/f1 to be 1.32 +0.21-0.17(stat.) +/- 0.05(syst.), assuming the SU(3)f (flavor) values for g2/f1 and f2/f1. Our results are all consistent with exact SU(3)f symmetry.Comment: Submitted to Physical Review Letters, 5 pages, 4 figure
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