251 research outputs found

    Physics of Single-Top Quark Production at Hadron Colliders

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    We discuss the physics of single-top quark production and decay at hadron colliders, such as the Tevatron, the \tevstar~and the LHC. Our study includes how to measure the mass and the width of the top quark produced from a {\hbox{single-tt}} or a single-tˉ\bar t process. We also show how to probe new physics by studying the couplings of tt-b{b}-WW and show what can be improved from measuring the production rate of single-top events. We also discuss how to probe CP properties of the top quark by measuring the single-top production rate. Finally, we present a Monte Carlo study on the detection of single-top events in hadron collisions.Comment: Thesis, 102 pages, Latex, needs 45 figures (not included). All Tex files and the associated analysis package ONETOP may be obtained via anonymous ftp at ftp://cteq14.pa.msu.edu/pub/carlson_d

    Probing New Physics from the Single-Top Production

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    We show that the production rate of the single-top quark event from the WW-gluon fusion process is sensitive to new physics which strongly modifies the interactions of the top quark. The measurement of its production rate gives the partial decay width of the top quark which combined with the branching ratio measurement from the ttˉt \bar t pair event determines the lifetime of the top quark.Comment: 7 pages, uuencoded PS file. Talk given by C.-P. Yuan at the Workshop on Physics of the Top Quark, IITAP, Iowa State University, Ames, Iowa, May 25 \& 26, 199

    Impact of anode layer thruster plumes on satellite communications

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76372/1/AIAA-1997-3067-147.pd

    Electromagnetic wave scattering experiments in Hall thruster plasma plumes

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76740/1/AIAA-1998-3642-699.pd

    Noncommutativity, generalized uncertainty principle and FRW cosmology

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    We consider the effects of noncommutativity and the generalized uncertainty principle on the FRW cosmology with a scalar field. We show that, the cosmological constant problem and removability of initial curvature singularity find natural solutions in this scenarios.Comment: 8 pages, to appear in IJT

    t→bWt \to b W in NonCommutative Standard Model

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    We study the top quark decay to b quark and W boson in the NonCommutative Standard Model (NCSM). The lowest contribution to the decay comes from the terms quadratic in the matrix describing the noncommutative (NC) effects while the linear term is seen to identically vanish because of symmetry. The NC effects are found to be significant only for low values of the NC characteristic scale.Comment: 11 page Latex file containing 2 eps figures (redrawn). More discussion included. To appear in PR

    Single Top Quark Production via FCNC Couplings at Hadron Colliders

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    We calculate single top-quark production at hadron colliders via the chromo-magnetic flavor-changing neutral current couplings tˉcg\bar tcg and tˉug\bar tug. We find that the strength for the anomalous tˉcg\bar tcg (tˉug\bar tug) coupling may be probed to κc/Λ=0.092TeV−1\kappa_c / \Lambda = 0.092 {TeV}^{-1} (κu/Λ=0.026TeV−1\kappa_u / \Lambda = 0.026 {TeV}^{-1}) at the Tevatron with 2fb−12 {fb}^{-1} of data and κc/Λ=0.013TeV−1\kappa_c / \Lambda = 0.013 {TeV}^{-1} (κu/Λ=0.0061TeV−1\kappa_u / \Lambda = 0.0061 {TeV}^{-1}) at the LHC with 10fb−110 {fb}^{-1} of data. The two couplings may be distinguished by a comparision of the single top signal with the direct top and top decay signals for these couplings.Comment: 18 pages, 6 figures, 3 table

    Direct Top Quark Production at Hadron Colliders as a Probe of New Physics

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    We examine the effect of an anomalous flavor changing chromomagnetic moment which allows direct top quark production (two partons combining into an unaccompanied single top quark in the s-channel) at hadron colliders. We consider both t-c-g and t-u-g couplings. We find that the anomalous charm quark coupling parameter κc/Λ\kappa_c / \Lambda can be measured down to .06TeV−1(.009TeV−1.06 TeV^{-1}(.009 TeV^{-1}) at the Tevatron with the Main Injector upgrade(LHC). The anomalous up quark coupling parameter κu/Λ\kappa_u / \Lambda can be measured to .02TeV−1(.003TeV−1.02 TeV^{-1}(.003 TeV^{-1}) at the Tevatron(LHC).Comment: 14 pages, Latex, requires feynm

    Constraints to Implementing the Essential Health Package in Malawi

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    Increasingly seen as a useful tool of health policy, Essential or Minimal Health Packages direct resources to interventions that aim to address the local burden of disease and be cost-effective. Less attention has been paid to the delivery mechanisms for such interventions. This study aimed to assess the degree to which the Essential Health Package (EHP) in Malawi was available to its population and what health system constraints impeded its full implementation. The first phase of this study comprised a survey of all facilities in three districts including interviews with all managers and clinical staff. In the second and third phase, results were discussed with District Health Management Teams and national level stakeholders, respectively, including representatives of the Ministry of Health, Central Medical Stores, donors and NGOs. The EHP in Malawi is focussing on the local burden of disease; however, key constraints to its successful implementation included a widespread shortage of staff due to vacancies but also caused by frequent trainings and meetings (only 48% of expected man days of clinical staff were available; training and meetings represented 57% of all absences in health centres). Despite the training, the percentage of health workers aware of vital diagnostic and therapeutic approaches to EHP conditions was weak. Another major constraint was shortages of vital drugs at all levels of facilities (e.g. Cotrimoxazole was sufficiently available to treat the average number of patients in only 27% of health centres). Although a few health workers noted some improvement in infrastructure and working conditions, they still considered them to be widely inadequate. In Malawi, as in similar resource poor countries, greater attention needs to be given to the health system constraints to delivering health care. Removal of these constraints should receive priority over the considerable focus on the development and implementation of essential packages of interventions
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