1,799 research outputs found

    Charge symmetry violation: a NNLO study of partonic observables

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    Charge and isospin symmetry violations to valence and sea distribution functions in the nucleon are evaluated (at low resolution scale) by means of a meson cloud model and light-cone quark wave functions. Their perturbative evolution are implemented at Next-to-next-to-leading order (NNLO) using an original evolution code in order to include the perturbatively generated strange - anti-strange asymmetry typical of the three loop evolution expansion. Charge symmetry violating QED effects are also added and the distributions, evolved at the experimental scale, are compared with available information. The role of non-perturbative effects is emphasized in the interpretation of the, so called, NuTeV anomaly and new experiments at very-high energy.Comment: revtex4, 7 pages, 3 figures; text improved, new comments and reference

    Possible Explanations for the NuTeV Weinberg Angle Measurement

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    The NuTeV collaboration has made an independent determination of the Weinberg angle by measuring charged and neutral-current cross sections from neutrino and antineutrino DIS on iron. Their value differs by 3 standard deviations from that obtained from measurements at the Z pole. We review this experiment and assess various possible explanations for this result, both within the Standard Model ("old physics") and outside the Standard Model ("new physics").Comment: QCD Down Under Workshop, CSSM, Adelaide, Australia, Mar 10-19, 2004; 6 pages, 3 figs; updated references on QCD effect

    Automated Fixing of Programs with Contracts

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    This paper describes AutoFix, an automatic debugging technique that can fix faults in general-purpose software. To provide high-quality fix suggestions and to enable automation of the whole debugging process, AutoFix relies on the presence of simple specification elements in the form of contracts (such as pre- and postconditions). Using contracts enhances the precision of dynamic analysis techniques for fault detection and localization, and for validating fixes. The only required user input to the AutoFix supporting tool is then a faulty program annotated with contracts; the tool produces a collection of validated fixes for the fault ranked according to an estimate of their suitability. In an extensive experimental evaluation, we applied AutoFix to over 200 faults in four code bases of different maturity and quality (of implementation and of contracts). AutoFix successfully fixed 42% of the faults, producing, in the majority of cases, corrections of quality comparable to those competent programmers would write; the used computational resources were modest, with an average time per fix below 20 minutes on commodity hardware. These figures compare favorably to the state of the art in automated program fixing, and demonstrate that the AutoFix approach is successfully applicable to reduce the debugging burden in real-world scenarios.Comment: Minor changes after proofreadin

    SLoMo: automated site localization of modifications from ETD/ECD mass spectra

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    Recently, software has become available to automate localization of phosphorylation sites from CID data and to assign associated confidence scores. We present an algorithm, SLoMo (Site Localization of Modifications), which extends this capability to ETD/ECD mass spectra. Furthermore, SLoMo caters for both high and low resolution data and allows for site-localization of any UniMod post-translational modification. SLoMo accepts input data from a variety of formats (e.g., Sequest, OMSSA). We validate SLoMo with high and low resolution ETD, ECD, and CID data

    Automatic Generation of RAMS Analyses from Model-based Functional Descriptions using UML State Machines

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    In today's industrial practice, safety, reliability or availability artifacts such as fault trees, Markov models or FMEAs are mainly created manually by experts, often distinctively decoupled from systems engineering activities. Significant efforts, costs and timely requirements are involved to conduct the required analyses. In this paper, we describe a novel integrated model-based approach of systems engineering and dependability analyses. The behavior of system components is specified by UML state machines determining intended/correct and undesired/faulty behavior. Based on this information, our approach automatically generates different dependability analyses in the form of fault trees. Hence, alternative system layouts can easily be evaluated. The same applies for simple variations of the logical input-output relations of logical units such as controllers. We illustrate the feasibility of our approach with the help of simple examples using a prototypical implementation of the presented concepts

    Electroweak Physics

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    The status of precision electroweak measurements as of summer 2002 is reviewed. The recent results on the anomalous magnetic moment of the muon and on neutrino-nucleon scattering are discussed. Precision results on the electroweak interaction obtained by the experiments at the SLC, LEP and TEVATRON colliders are presented. The experimental results are compared with the predictions of the minimal Standard Model and are used to constrain its parameters, including the mass of the Higgs boson. The final LEP results on the direct search for the Higgs boson of the Standard Model are presented.Comment: Plenary talk presented at the 31st ICHEP, Amsterdam, The Netherlands, July 24-31, 200

    Tests4Py: A Benchmark for System Testing

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    Benchmarks are among the main drivers of progress in software engineering research, especially in software testing and debugging. However, current benchmarks in this field could be better suited for specific research tasks, as they rely on weak system oracles like crash detection, come with few unit tests only, need more elaborative research, or cannot verify the outcome of system tests. Our Tests4Py benchmark addresses these issues. It is derived from the popular BugsInPy benchmark, including 30 bugs from 5 real-world Python applications. Each subject in Tests4Py comes with an oracle to verify the functional correctness of system inputs. Besides, it enables the generation of system tests and unit tests, allowing for qualitative studies by investigating essential aspects of test sets and extensive evaluations. These opportunities make Tests4Py a next-generation benchmark for research in test generation, debugging, and automatic program repair.Comment: 5 pages, 4 figure

    Reassessment of the NuTeV determination of the Weinberg angle

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    In light of the recent discovery of the importance of the isovector EMC effect for the interpretation of the NuTeV determination of sin^2 theta_W, it seems timely to reassess the central value and the errors on this fundamental Standard Model parameter derived from the NuTeV data. We also include earlier work on charge symmetry violation and the recent limits on a possible asymmetry between s and \bar{s} quarks. With these corrections we find a revised NuTeV result of sin^2 theta_W = 0.2232 \pm 0.0013(stat) \pm 0.0024(syst), which is in excellent agreement with the running of sin^2 theta_W predicted by the Standard Model.Comment: 4 pages, one figur
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