6,091 research outputs found

    Nuclear modification of valence-quark distributions and its effects on NuTeV sin^2 theta_W anomaly

    Full text link
    We investigated a nuclear modification difference between up- and down-valence quark distributions by analyzing structure function F_2 and Drell-Yan cross-section ratios. Although nuclear modifications of the valence-quark distributions themselves are rather well determined, it is difficult to find their difference from the present data. We estimated such an effect on the NuTeV sin^2 theta_W value and its uncertainty by the Hessian method. At this stage, it is not large enough to explain the whole NuTeV anomaly. However, the modification difference cannot be precisely determined, so that further studies are needed.Comment: 3 pages, LaTeX, 1 eps file, to be published in Proceedings of the 6th International Workshop on Neutrino Factories and Superbeams (NuFact04

    Multi-level manual and autonomous control superposition for intelligent telerobot

    Get PDF
    Space telerobots are recognized to require cooperation with human operators in various ways. Multi-level manual and autonomous control superposition in telerobot task execution is described. The object model, the structured master-slave manipulation system, and the motion understanding system are proposed to realize the concept. The object model offers interfaces for task level and object level human intervention. The structured master-slave manipulation system offers interfaces for motion level human intervention. The motion understanding system maintains the consistency of the knowledge through all the levels which supports the robot autonomy while accepting the human intervention. The superposing execution of the teleoperational task at multi-levels realizes intuitive and robust task execution for wide variety of objects and in changeful environment. The performance of several examples of operating chemical apparatuses is shown

    Nuclear corrections of parton distribution functions

    Full text link
    We report global analysis results of experimental data for nuclear structure-function ratios F_2^A/F_2^{A'} and proton-nucleus Drell-Yan cross-section ratios sigma_{DY}^{pA}/sigma_{DY}^{pA'} in order to determine optimum parton distribution functions (PDFs) in nuclei. An important point of this analysis is to show uncertainties of the distributions by the Hessian method. The results indicate that the uncertainties are large for gluon distributions in the whole x region and for antiquark distributions at x>0.2. We provide a code for calculating any nuclear PDFs at given x and Q^2 for general users. They can be used for calculating high-energy nuclear reactions including neutrino-nucleus interactions, which are discussed at this workshop.Comment: 1+6 pages, LaTeX, 10 eps files, espcrc2.sty, to be published in Nucl. Phys. B Supplements, Proceedings of the Third International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region (NuInt04), Gran Sasso, Italy, March 17-21, 2004. Nuclear PDF library is available at http://hs.phys.saga-u.ac.jp/nuclp.htm

    A possible nuclear effect on the NuTeV sin^2 theta_W anomaly

    Full text link
    We investigate a possible explanation for the NuTeV anomaly in terms of a nuclear correction difference between u_v and d_v distributions. Analyzing deep elastic scattering and Drell-Yan data for nuclear targets, we try to determine the correction difference and its effect on the anomaly. We find that the difference cannot be precisely determined at this stage due to the lack of data which are sensitive to the difference. Therefore, it is difficult to draw a solid conclusion about its effect although the anomaly could be explained, at least partially, by this kind of nuclear correction.Comment: 3 pages, 1 figure, to be published in the proceedings of the XVIIth Particles and Nuclei International Conference (PANIC), Santa Fe, New Mexico, USA, October 24-28, 200

    Hybrid ECAL: Optimization and Related Developments

    Full text link
    Hybrid ECAL is a cost-conscious option of electromagnetic calorimeter (ECAL) for particle flow calorimetry to be used in a detector of International Linear Collider (ILC). It is a combination of silicon-tungsten ECAL, which realizes high granularity and robust measurement of electromagnetic shower, and scintillator-tungsten ECAL, which gives affordable cost with similar performance to silicon. Optimization and a data acquisition trial in a test bench for the hybrid ECAL are described in this article.Comment: 7 pages, 4 figures, Talk presented at the International Workshop on Future Linear Colliders (LCWS14), Belgrade, Serbia, 6-10 October 201

    Room temperature ferromagnetic behavior in the hollandite-type titanium oxide

    Get PDF
    A hollandite-type K(x)Ti(8)O(16) polycrystalline sample has been prepared and studied by magnetization, resistivity and x-ray photoelectron spectroscopy (XPS). Room temperature ferromagnetic behavior is observed in the magnetic hysteresis measurement. The sample shows a semiconductive temperature dependence in the resistivity measurement. Analysis of the Ti 2p(3/2) core-level XPS spectrum indicates that the titanium ions have a mixed valence of Ti(4+) and Ti(3+). In addition, the valence band spectrum reveals that the 3d electrons tend to localize on Ti(3+) ions in the hollandite-type TiO(2) lattice. Also, analysis of the valence band spectrum shows that the prepared sample is a wide-gap oxide with a band gap of 3.6 eV. These results indicate that the present hollandite-type K(x)Ti(8)O(16) sample can be classified as a TiO(2)-based wide-gap semiconductor with Curie temperature above room temperature. Room temperature ferromagnetism (RTFM) decreases in the sample prepared under a strong reducing gas atmosphere, accompanied with the decrease in the resistivity. The results imply that the localized 3d electrons are responsible for the RTFM of the K(x)Ti(8)O(16) sample
    • …
    corecore