1,947 research outputs found

    Proportional drift tubes for large area muon detectors

    Get PDF
    A proportional drift chamber which consists of eight rectangular drift tubes with cross section of 10 cm x 5 cm, a sense wire of 100 micron phi gold-plated tungsten wire and the length of 6 m, was tested using cosmic ray muons. Spatial resolution (rms) is between 0.5 and 1 mm over drift space of 50 mm, depending on incident angle and distance from sense wire

    Distinct doping dependences of the pseudogap and superconducting gap La2−x_{2-x}Srx_{x}CuO4_4 cuprate superconductors

    Full text link
    We have performed a temperature-dependent angle-integrated photoemission study of lightly-doped to heavily-overdoped La2−x_{2-x}Srx_{x}CuO4_4 and oxygen-doped La2_2CuO4.10_{4.10}. We found that both the magnitude Δ\Delta* of the (small) pseudogap and the temperature \textit{T}* at which the pseudogap is opened increases with decreasing hole concentration, consistent with previous studies. On the other hand, the superconducting gap Δsc\Delta_{sc} was found to remain small for decreasing hole concentration. The results can be explained if the superconducting gap opens only on the Fermi arc around the nodal (0,0)-(π,π\pi,\pi) direction while the pseudogap opens around ∼\sim(π\pi, 0).Comment: 4 pages, 3 figure

    Coherent quasi-particles-to-incoherent hole-carriers crossover in underdoped cuprates

    Full text link
    In underdoped cuprates, only a portion of the Fermi surface survives as Fermi arcs due to pseudogap opening. In hole-doped La2_{2}CuO4_4, we have deduced the "coherence temperature" TcohT_{coh} of quasi-particles on the Fermi arc above which the broadened leading edge position in angle-integrated photoemission spectra is shifted away from the Fermi level and the quasi-particle concept starts to lose its meaning. TcohT_{coh} is found to rapidly increase with hole doping, an opposite behavior to the pseudogap temperature T∗T^*. The superconducting dome is thus located below both T∗T^* and TcohT_{coh}, indicating that the superconductivity emerges out of the coherent Fermionic quasi-particles on the Fermi arc. TcohT_{coh} remains small in the underdoped region, indicating that incoherent charge carriers originating from the Fermi arc are responsible for the apparently metallic transport at high temperatures

    Measurement of the cross-section and forward-backward charge asymmetry for the b and c-quark in e+e- annihilation with inclusive muons at sqrt(s) = 58 GeV

    Full text link
    We have studied inclusive muon events using all the data collected by the TOPAZ detector at sqrt(s)=58 GeV with an integrated luminosity of 273pb-1. From 1328 inclusive muon events, we measured the ratio R_qq of the cross section for qq-bar production to the total hadronic cross section and forward-backward asymmetry A^q_FB for b and c quarks. The obtained results are R_bb = 0.13+-0.02(stat)+-0.01(syst), R_cc = 0.36+-0.05(stat)+-0.05(syst), A^b_FB = -0.20+-0.16(stat)+-0.01(syst) and A^c_FB = -0.17+-0.14(stat)+-0.02(syst), in fair agreement with a prediction of the standard model.Comment: To be published in EPJ C. 24 pages, 12 figure

    A Measurement of the D∗±D^{*\pm} Cross Section in Two-Photon Processes

    Get PDF
    We have measured the inclusive D∗±D^{*\pm} production cross section in a two-photon collision at the TRISTAN e+e−e^+e^- collider. The mean s\sqrt{s} of the collider was 57.16 GeV and the integrated luminosity was 150 pb−1pb^{-1}. The differential cross section (dσ(D∗±)/dPTd\sigma(D^{*\pm})/dP_T) was obtained in the PTP_T range between 1.6 and 6.6 GeV and compared with theoretical predictions, such as those involving direct and resolved photon processes.Comment: 8 pages, Latex format (article), figures corrected, published in Phys. Rev. D 50 (1994) 187

    K0(K0ˉ)K^0(\bar{K^0}) Production in Two-Photon Processes at TRISTAN

    Full text link
    We have carried out an inclusive measurement of K0(K0ˉ)K^0(\bar{K^0}) production in two-photon processes at TRISTAN. The mean s\sqrt{s} was 58 GeV and the integrated luminosity was 199 pb−1^{-1}. High-statistics KsK_s samples were obtained under such conditions as no-, anti-electron, and remnant-jet tags. The remnant-jet tag, in particular, allowed us, for the first time, to measure the cross sections separately for the resolved-photon and direct processes.Comment: 20 pages, Latex format, 4 figures and KEK-mark included. Table 1 revised. To be published in Phys. Lett.

    Measurement of inclusive electron cross section in γγ\gamma \gamma collisions at TRISTAN

    Full text link
    We have studied open charm production in γγ\gamma \gamma collisions with the TOPAZ detector at the TRISTAN e+e−e^{+}e^{-} collider. In this study, charm quarks were identified by electrons (and positrons) from semi-leptonic decays of charmed hadrons. The data corresponded to an integrated luminosity of 95.3 pb−1^{-1} at a center-of-mass energy of 58 GeV. The results are presented as the cross sections of inclusive electron production in γγ\gamma \gamma collisions with an anti-tag condition, as well as the subprocess cross sections, which correspond to resolved-photon processes. The latter were measured by using a sub-sample with remnant jets. A comparison with various theoretical predictions based on direct and resolved-photon processes showed that our data prefer that with relatively large gluon contents in a photon at small x(x≤0.1)x (x \le 0.1), with the next-to-leading order correction, and with a charm-quark mass of 1.3 GeV.Comment: 26 pages, Latex format (article), 5 figures included, to be published in Phys. Lett.
    • …
    corecore