20,059 research outputs found

    A DAQ System for Linear Collider TPC Prototypes based on the ALEPH TPC Electronics

    Full text link
    Within the international studies of a high energy linear electron positron collider, several groups are developing and testing prototypes for a Linear Collider TPC. This detector is planned to be used as a central part in the tracking system of a detector at such a machine. In this note we describe a DAQ system, which has been developed for the use in tests of TPC prototypes. It is based on electronics used at the ALEPH experiment at CERN.Comment: 15 pages, 4 figure

    NewsPad: Designing for Collaborative Storytelling in Neighborhoods

    Full text link
    This paper introduces design explorations in neighborhood collaborative storytelling. We focus on blogs and citizen journalism, which have been celebrated as a means to meet the reporting needs of small local communities. These bloggers have limited capacity and social media feeds seldom have the context or readability of news stories. We present NewsPad, a content editor that helps communities create structured stories, collaborate in real time, recruit contributors, and syndicate the editing process. We evaluate NewsPad in four pilot deployments and find that the design elicits collaborative story creation.Comment: NewsPad: designing for collaborative storytelling in neighborhoods. In Proceedings of the extended abstracts of the 32nd annual ACM conference on Human factors in computing systems (CHI EA 2014

    Galaxy types in the Sloan Digital Sky Survey using supervised artificial neural networks

    Get PDF
    Supervised artificial neural networks are used to predict useful properties of galaxies in the Sloan Digital Sky Survey, in this instance morphological classifications, spectral types and redshifts. By giving the trained networks unseen data, it is found that correlations between predicted and actual properties are around 0.9 with rms errors of order ten per cent. Thus, given a representative training set, these properties may be reliably estimated for galaxies in the survey for which there are no spectra and without human intervention

    Bivariate galaxy luminosity functions in the Sloan Digital Sky Survey

    Get PDF
    Bivariate luminosity functions (LFs) are computed for galaxies in the New York Value-Added Galaxy Catalogue, based on the Sloan Digital Sky Survey Data Release 4. The galaxy properties investigated are the morphological type, inverse concentration index, SĂ©rsic index, absolute effective surface brightness (SB), reference frame colours, absolute radius, eClass spectral type, stellar mass and galaxy environment. The morphological sample is flux limited to galaxies with r < 15.9 and consists of 37 047 classifications to an rms accuracy of ± half a class in the sequence E, S0, Sa, Sb, Sc, Sd, Im. These were assigned by an artificial neural network, based on a training set of 645 eyeball classifications. The other samples use r < 17.77 with a median redshift of z∌ 0.08, and a limiting redshift of z < 0.15 to minimize the effects of evolution. Other cuts, for example in axis ratio, are made to minimize biases. A wealth of detail is seen, with clear variations between the LFs according to absolute magnitude and the second parameter. They are consistent with an early-type, bright, concentrated, red population and a late-type, faint, less concentrated, blue, star-forming population. This bimodality suggests two major underlying physical processes, which in agreement with previous authors we hypothesize to be merger and accretion, associated with the properties of bulges and discs, respectively. The bivariate luminosity–SB distribution is fit with the ChoƂoniewski function (a Schechter function in absolute magnitude and Gaussian in SB). The fit is found to be poor, as might be expected if there are two underlying processes

    Light-cone sum rules for B→πB \to \pi form factors revisited

    Get PDF
    We reconsider and update the QCD light-cone sum rules for B→πB\to \pi form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The MSˉ\bar{MS} bb-quark mass is employed, instead of the one-loop pole mass used in the previous analyses. The light-cone sum rule for fBπ+(q2)f^+_{B\pi}(q^2) is fitted to the measured q2q^2-distribution in B→πlÎœlB\to \pi l \nu_l, fixing the input parameters with the largest uncertainty: the Gegenbauer moments of the pion distribution amplitude. For the B→πB\to \pi vector form factor at zero momentum transfer we predict fBπ+(0)=0.26−0.03+0.04f^+_{B\pi}(0)= 0.26^{+0.04}_{-0.03}. Combining it with the value of the product ∣VubfBπ+(0)∣|V_{ub}f^+_{B\pi}(0)| extracted from experiment, we obtain ∣Vub∣=(3.5±0.4±0.2±0.1)×10−3|V_{ub}|=(3.5\pm 0.4\pm 0.2\pm 0.1) \times 10^{-3}. In addition, the scalar and penguin B→πB\to \pi form factors fBπ0(q2)f^0_{B\pi}(q^2) and fBπT(q2)f^T_{B\pi}(q^2) are calculated.Comment: 33 pages, 7 figures, one figure and a few comments added, version to appear in JHE

    Producing the docile body: analysing Local Area Under-performance Inspection (LAUI)

    Get PDF
    Sir Michael Wilshaw, the head of the Office for Standards in Education (OfSTED), declared a 'new wave' of Local Area Under-performance Inspections (LAUI) of schools 'denying children the standard of education they deserve'. This paper examines how the threat of LAUI played out over three mathematics lessons taught by a teacher in her first year in the profession. A Foucauldian approach is mobilised with regard to disciplinary power and 'docile bodies'. The paper argues that, in the case in point, LAUI was a tool mediating performative conditions and, ultimately, the docile body. The paper will be of concern to policy sociologists, teachers, school leaders, and those interested in school inspection

    B ->PV Decays in the QCD Improved Factorization Approach

    Full text link
    Motivated by recent CELO measurements and the progress of the theory of B decays, we investigate B→PV(P=π,K.V=K∗,ρ,ω)B\to P V(P=\pi,K. V= K^{*},\rho,\omega) decay modes in the framework of QCD improved factorization. We find that all the measured branching ratios are well accommodated in the reasonable parameter space and predictions for the other decay modes are well below the experimental upper limits. We also have calculated CP asymmetries in these decay modes.Comment: 24 pages, LaTex-2e, typos correcte

    Heavy to Light Meson Exclusive Semileptonic Decays in Effective Field Theory of Heavy Quark

    Full text link
    We present a general study on exclusive semileptonic decays of heavy (B, D, B_s) to light (pi, rho, K, K^*) mesons in the framework of effective field theory of heavy quark. Transition matrix elements of these decays can be systematically characterized by a set of wave functions which are independent of the heavy quark mass except for the implicit scale dependence. Form factors for all these decays are calculated consistently within the effective theory framework using the light cone sum rule method at the leading order of 1/m_Q expansion. The branching ratios of these decays are evaluated, and the heavy and light flavor symmetry breaking effects are investigated. We also give comparison of our results and the predictions from other approaches, among which are the relations proposed recently in the framework of large energy effective theory.Comment: 18 pages, ReVtex, 5 figures, added references and comparison of results, and corrected signs in some formula

    Heavy-to-Light Meson Transitions in QCD

    Get PDF
    I discuss QCD sum rules determinations of the form factors governing the decay B→π(ρ)â„“ÎœB \to \pi (\rho) \ell \nu. For some of these form factors the computed dependence on the momentum transferred does not agree with the expectation from the nearest pole dominance hypothesis. Relations are observed among the form factors, that seem to be compatible with equations recently derived by B.Stech. The measurement of a number of color suppressed nonleptonic B decay rates could shed light on the accuracy of the calculation of these form factors and on the factorization approximation.Comment: LaTex, 7 pages, 2 figures (files included). Talk given at the 6th International Symposium on Heavy Flavours, Pisa, 6-10 June 199
    • 

    corecore