26,825 research outputs found

    THE INVESTMENT PROJECT PIPELINE COST ESCALATION, LEAD-TIME, SUCCESS, FAILURE AND SPEED1

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    As they involve expectations about the future and long lead times for planning and construction, the evolution of investment projects is usually complex and volatile. This paper analyses an important aspect of this volatility by studying the nature of the investment process, from the initial bright idea to the final construction and operational phase of a project. We refer to this process as the “project pipeline”. Using a rich source of information on recent Australian resource development projects, an index-number approach is employed to measure the escalation of costs of projects in the pipeline and the time spent there (the lead time). The determinants of the probability of ultimate success of projects is analysed with a binary choice model. Finally, a Markov chain approach is used to model the transitions of projects from one stage in the pipeline to the next, and to examine the implications of regulatory reform that has the effect of speeding up the flow of projects.

    Investigation of Top quark spin correlations at hadron collider

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    We report on our results about hadronic ttˉt\bar t production at NLO QCD including t,tˉt, \bar t spin effects, especially on ttˉt\bar t spin correlations.Comment: talk given at the 32nd International Conference on High Energy Physics (ICHEP'04), Beijing, China, 16-22 Aug. 200

    Unusual persistence of superconductivity against high magnetic fields in the strongly-correlated iron-chalcogenide film FeTe:Ox_{x}

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    We report an unusual persistence of superconductivity against high magnetic fields in the iron chalcogenide film FeTe:Ox_{x} below ~ 2.5 K. Instead of saturating like a mean-field behavior with a single order parameter, the measured low-temperature upper critical field increases progressively, suggesting a large supply of superconducting states accessible via magnetic field or low-energy thermal fluctuations. We demonstrate that superconducting states of finite momenta can be realized within the conventional theory, despite its questionable applicability. Our findings reveal a fundamental characteristic of superconductivity and electronic structure in the strongly-correlated iron-based superconductors.Comment: 10 pages, 3 figure

    Spin properties of top quark pairs produced at hadron colliders

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    We discuss the spin properties of top quark pairs produced at hadron colliders at next-to-leading order in the coupling constant alpha_s of the strong interaction. Specifically we present, for some decay channels, results for differential angular distributions that are sensitive to t tbar spin correlations.Comment: Invited talk given by A. Brandenburg at the Cracow epiphany conference on heavy flavours, 3 - 6 January 2003, Cracow, Polan

    Mixed QCD and Weak Corrections to ttˉt\bar{t} Production by Quark-Antiquark Annihilation

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    We report on our computation of the mixed QCD and weak corrections to qqˉttˉq {\bar q} \to t\bar{t} including t,tˉt, \bar t spin effects, in particular on single top spin asymmetries.Comment: Talk given at "International Conference on QCD and Hadronic Physics", Beijing, China, 16-20 Jun 200

    Top quark spin correlations at hadron colliders: Predictions at next-to-leading order QCD

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    The collider experiments at the Tevatron and the LHC will allow for detailed investigations of the properties of the top quark. This requires precise predictions of the hadronic production of ttˉt\bar t pairs and of their subsequent decays. In this Letter we present for the reactions ppˉ,ppttˉ+X+Xp {\bar p}, p p \to t{\bar t} + X \to \ell^+\ell'^-X the first calculation of the dilepton angular distribution at next-to-leading order (NLO) in the QCD coupling, keeping the full dependence on the spins of the intermediate ttˉt\bar{t} state. The angular distribution reflects the degree of correlation of the tt and tˉ\bar t spins which we determine for different choices of tt and tˉ\bar t spin bases. In the case of the Tevatron, the QCD corrections are sizeable, and the distribution is quite sensitive to the parton content of the proton.Comment: 9 pages, 2 figure

    Top Quark Pair Production and Decay including Spin Effects at Hadron Colliders: Predictions at NLO QCD

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    Top quark-antiquark (ttˉt\bar t) pairs will be produced copiously at the Tevatron collider and in huge numbers at the LHC. This will make possible detailed investigations of the properties and interactions of this quark flavor. The analysis and interpretation of future data requires precise predictions of the hadronic production of ttˉt\bar t pairs and of their subsequent decays. In this talk the reactions ppˉ,ppttˉ+Xl+l+Xp {\bar p}, p p \to t{\bar t} + X \to l^+ l'^- + X are considered and results are presented of our calculation of the dilepton angular distribution at next-to-leading order QCD, keeping the full dependence on the spins of the intermediate ttˉt\bar{t} state. The angular distribution is determined for different choices of reference axes that can be identified with the tt and tˉ\bar t spin axes. While the QCD corrections to the leading-order distribution turn out to be small in the case of the LHC, we find them to be sizeable in the case of the Tevatron and find, moreover, the angular distribution to be sensitive to the parton content of the proton.Comment: Talk given at 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics", Beijing, China, 8-13, 200

    Enhanced flux pinning in YBa2Cu3O7-d films by nano-scaled substrate surface roughness

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    Nano-scaled substrate surface roughness is shown to strongly influence the critical current density Jc in YBCO films made by pulse-laser-deposition on the crystalline LaAlO3 substrates consisting of two separate twin-free and twin-rich regions. The nano-scaled corrugated surface was created in the twin-rich region during the deposition process. Using magneto-optical imaging techniques coupled with optical and atomic force microscopy, we observed an enhanced flux pinning in the YBCO films in the twin-rich region, resulted in \~30% increase in Jc, which was unambiguously confirmed by the direct transport measurement.Comment: 16 pages, 3 figures, accepted by Applied Physics Letter
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