5,682 research outputs found

    WHIZARD 2.2 for Linear Colliders

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    We review the current status of the WHIZARD event generator. We discuss, in particular, recent improvements and features that are relevant for simulating the physics program at a future Linear Collider.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS13), Tokyo, Japan, 11-15 November 201

    Growth, globalization, and gains from the Uruguay Round

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    Emphasizing the importance of evaluating the Uruguay Round in the context of a changing world economy, the authors base their projections on a model that incorporates certain economic shifts: 1) that the center of economic gravity will shift toward the South and toward Asia (a shift that is already under way and shows no signs of abating), and 2) that the pattern of comparative advantage will continue to change, with the East Asian economies gaining comparative advantage in the production of physical and human-capital-intensive products. The authors argue that these changes in the global economy significantly affect their analysis of the Uruguay round reforms, for two reasons. First, with the global distribution of trade and production shifting toward Asia, the deeper Uruguay Round cuts inthat region become more important, giving rise to a 17 percent increase in the proportionate welfare gain after implementation of tariff cuts. Second, without the Round, almost all of the bilateral quotas associated with the Multifibre Arrangement (MFA) would have become more binding and the resulting distortion would have been significantly greater. In this analysis, the global gain from MFA reform is 60 percent greater than it would have been without taking into account the effects of growth. Of course, procedures for implementation of the MFA reforms are more complex than they have conveyed for purposes of analysis. In practice, one must also consider the impact of accel quota growth under the Agreement on Textiles and Clothing. But even when the Agreement on Textiles and Clothing is implemented over the period for which projections were made, quota rents rise for many bilateral flows. This is a consequence both of shifts in comparative advantage toward the supplying countries and of simultaneous cuts in tariffs on textiles and clothing. The projections approach used here may be viewed as a logical extension of the growing econometric literature seeking to explain the determinants of economic growth through regression analysis. By offering a bridge between econometric evidence and computable general equilibrium modeling, the authors hope to combine the two approaches to help shed light on the interaction between trade reform and economic growth.Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Export Competitiveness,Globalization and Financial Integration,Environmental Economics&Policies,Trade and Regional Integration,Achieving Shared Growth,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT

    QCD NLO with Powheg matching and top threshold matching in WHIZARD

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    We present the status of the automation of NLO processes within the event generator WHIZARD. The program provides an automated FKS subtraction and phase space integration over the FKS regions, while the (QCD) NLO matrix element is accessed via the Binoth Les Houches Interface from an externally linked one-loop program. Massless and massive test cases and validation are shown for several e+e- processes. Furthermore, we discuss work in progress and future plans. The second part covers the matching of the NRQCD prediction with NLL threshold resummation to the NLO continuum top pair production at lepton colliders. Both the S-wave and P-wave production of the top pair are taken into account in the resummation. The inclusion in WHIZARD allows to study more exclusive observables than just the total cross section and automatically accounts for important electroweak and relativistic corrections in the threshold region.Comment: 9 pages, 3 figures, Talk given at 12th International Symposium on Radiative Corrections (Radcor 2015) and LoopFest XIV (Radiative Corrections for the LHC and Future Colliders); v2: reference adde

    Ground State and Resonances in the Standard Model of Non-relativistic QED

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    We prove existence of a ground state and resonances in the standard model of the non-relativistic quantum electro-dynamics (QED). To this end we introduce a new canonical transformation of QED Hamiltonians and use the spectral renormalization group technique with a new choice of Banach spaces.Comment: 50 pages change

    Influence of Forming Rate on the Microstructure and Properties of Materials Subjected to Electromagnetic Forming

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    Electromagnetic high speed forming has been known since the 1960's and is successfully used for frictional connexions. In addition to joining, other applications of the process include coining, stamping and cutting. Regarding product quality and manufacturing costs, the process is superior to other methods and yet its utilisation can still be extended. The synopsis of the material's microstructure and properties owing to electromagnetic forming, which is given by this article, clarifies the processes from a materials science point of view. This will not only represent an academic view point but also provide insight into a potential expansion of the process to other areas of application

    Reliable solid-state circuits Semiannual report no. 2, Jun. 1 - Nov. 30, 1965

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    Pulse width modulator and other microminiaturized electronic equipment for space age application

    Modern Particle Physics Event Generation with WHIZARD

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    We describe the multi-purpose Monte-Carlo event generator WHIZARD for the simulation of high-energy particle physics experiments. Besides the presentation of the general features of the program like SM physics, BSM physics, and QCD effects, special emphasis will be given to the support of the most accurate simulation of the collider environments at hadron colliders and especially at future linear lepton colliders. On the more technical side, the very recent code refactoring towards a completely object-oriented software package to improve maintainability, flexibility and code development will be discussed. Finally, we present ongoing work and future plans regarding higher-order corrections, more general model support including the setup to search for new physics in vector boson scattering at the LHC, as well as several lines of performance improvements.Comment: 7 pages; contribution to the proceedings of the conference "ACAT 2014 (Advanced Computing and Analysis Techniques in physics)", Prague, Czech Republic, September 201

    Top Physics in WHIZARD

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    In this talk we summarize the top physics setup in the event generator WHIZARD with a main focus on lepton colliders. This includes full six-, eight- and ten-fermion processes, factorized processes and spin correlations. For lepton colliders, QCD NLO processes for top quark physics are available and will be discussed. A special focus is on the top-quark pair threshold, where a special implementation combines a non-relativistic effective field theory calculation augmented by a next-to-leading threshold logarithm resummation with a continuum relativistic fixed-order QCD NLO simulation.Comment: 6 pages, 2 figures, Talk presented at the International Workshop on Future Linear Colliders (LCWS15), Whistler, Canada, 2-6 November 201

    Field evolution of the magnetic structures in Er2_2Ti2_2O7_7 through the critical point

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    We have measured neutron diffraction patterns in a single crystal sample of the pyrochlore compound Er2_2Ti2_2O7_7 in the antiferromagnetic phase (T=0.3\,K), as a function of the magnetic field, up to 6\,T, applied along the [110] direction. We determine all the characteristics of the magnetic structure throughout the quantum critical point at HcH_c=2\,T. As a main result, all Er moments align along the field at HcH_c and their values reach a minimum. Using a four-sublattice self-consistent calculation, we show that the evolution of the magnetic structure and the value of the critical field are rather well reproduced using the same anisotropic exchange tensor as that accounting for the local paramagnetic susceptibility. In contrast, an isotropic exchange tensor does not match the moment variations through the critical point. The model also accounts semi-quantitatively for other experimental data previously measured, such as the field dependence of the heat capacity, energy of the dispersionless inelastic modes and transition temperature.Comment: 7 pages; 8 figure

    Tunneling magnetoresistance in devices based on epitaxial NiMnSb with uniaxial anisotropy

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    We demonstrate tunnel magnetoresistance (TMR) junctions based on a tri layer system consisting of an epitaxial NiMnSb, aluminum oxide and CoFe tri layer. The junctions show a tunnelling magnetoresistance of Delta R/R of 8.7% at room temperature which increases to 14.7% at 4.2K. The layers show clear separate switching and a small ferromagnetic coupling. A uniaxial in plane anisotropy in the NiMnSb layer leads to different switching characteristics depending on the direction in which the magnetic field is applied, an effect which can be used for sensor applications.Comment: 8 pages, 3 figures, submitted to Appl. Phys. Let
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