810 research outputs found

    A Survey of Lepton Number Violation Via Effective Operators

    Full text link
    We survey 129 lepton number violating effective operators, consistent with the minimal Standard Model gauge group and particle content, of mass dimension up to and including eleven. Upon requiring that each one radiatively generates the observed neutrino masses, we extract an associated characteristic cutoff energy scale which we use to calculate other observable manifestations of these operators for a number of current and future experimental probes, concentrating on lepton number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson, lepton, and gauge boson decays. We also consider searches at hadron/lepton collider facilities in anticipation of the LHC and the future ILC. We find that some operators are already disfavored by current data, while more are ripe to be probed by next-generation experiments. We also find that our current understanding of lepton mixing disfavors a subset of higher dimensional operators. While neutrinoless double-beta decay is the most promising signature of lepton number violation for the majority of operators, a handful is best probed by other means. We argue that a combination of constraints from various independent experimental sources will help to pinpoint the ``correct'' model of neutrino mass, or at least aid in narrowing down the set of possibilities.Comment: 34 pages, 10 eps figures, 1 tabl

    Students' mental prototypes for functions and graphs

    Get PDF
    This research study investigates the concept of function developed by students studying English A-level mathematics. It shows that, while students may be able to use functions in their practical mathematics, their grasp of the theoretical nature of the function concept may be tenuous and inconsistent. The hypothesis is that students develop prototypes for the function concept in much the same way as they develop prototypes for concepts in everyday life. The definition of the function concept, though given in the curriculum, is not stressed and proves to be inoperative, with their understanding of the concept reliant on properties of familiar prototype examples: those having regular shaped graphs, such as x2 or sin*, those often encountered (possibly erroneously), such as a circle, those in which y is defined as an explicit formula in x, and so on. Investigations reveal significant misconceptions. For example, threequarters of a sample of students starting a university mathematics course considered that a constant function was not a function in either its graphical or algebraic forms, and threequarters thought that a circle is a function. This reveals a wide gulf between the concepts as perceived to be taught and as actually learned by the students

    Peculiarities of the function of cardiomyocytes in patients with ischemic heart disease associated with diabetes mellitus type 2

    Get PDF
    The functional activity of myocardium in patients with type 2 diabetes mellitus(T2DM) and coronary heart disease (CAD) was studied. The study included patients with CAD with T2DM as representatives of the main group, the comparison group consisted of patients with univariant course of ischemic heart disease without violation of carbohydrate metabolism. Contractile activity of the myocardium was evaluated by the inotroic reaction of isolated trabeculae of patients according to the Protocol tests "Post-rest" and "Ekstrasistoliei test". As a result, it was found that rhythm-inotropic myocardial response in patients with comorbid pathology persists to a greater extent than in the one-dimensional flow of CAD

    Research of factors affecting the development of municipalities in Russia: creating a database for econometric modeling

    Get PDF
    This paper describes the preparatory stage of forming a database for the study of factors affecting the development of municipalities in Russia. The sources of information were identified and the combination of information from various databases was used in order to significantly expand the system of indicators for subsequent research. The created system of indicators is comparable with the systems of indicators used in foreign studies and will allow to identify similarities and differences in the behavior of municipalities of Russia and foreign countries. The generated database is panel data, which is enough for applying modern econometric methods for analyzing panel data, in particular, using regression models with fixed or random effects

    Testing the Higgs Mechanism in the Lepton Sector with multi-TeV e+e- Collisions

    Full text link
    Multi-TeV e+e- collisions provide with a large enough sample of Higgs bosons to enable measurements of its suppressed decays. Results of a detailed study of the determination of the muon Yukawa coupling at 3 TeV, based on full detector simulation and event reconstruction, are presented. The muon Yukawa coupling can be determined with a relative accuracy of 0.04 to 0.08 for Higgs bosons masses from 120 GeV to 150 GeV, with an integrated luminosity of 5 inverse-ab. The result is not affected by overlapping two-photon background.Comment: 6 pages, 2 figures, submitted to J Phys G.: Nucl. Phy

    Development of Readout Interconnections for the Si-W Calorimeter of SiD

    Full text link
    The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.Comment: 8 pages + title, 6 figure
    corecore