2,398 research outputs found

    Consistency Conditions for AdS/CFT Embeddings

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    The group embeddings used in orbifolding the AdS/CFT correspondence to arrive at quiver gauge field theories are studied for both supersymmetric and non-supersymmetric cases. For an orbifold AdS5×S5/ΓAdS_5 \times S^5/\Gamma the conditions for embeddings of the finite group Γ\Gamma in the SU(4)∌O(6)SU(4) \sim O(6) isotropy of S5S^5 are stated in the form of consistency rules, both for Abelian and Non-Abelian Γ\Gamma.Comment: 10 pages LaTe

    Editorial: In use, in situ: extending field research methods

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    A case for evaluating in use and in-situ Many authors have argued the need for a broader understanding of context and the situatedness of activity when approaching the evaluation of systems. However, prevailing practice often still tends towards attempting to understand the use of designed artefacts by focusing on a core set of tasks that are thought to define the system. A consequence of such focus is that other tasks are considered peripheral and outside the scope of design and evaluation activities. To illustrate the point, consider the experience, familiar to many of us, of being involved in an evaluation activity where participants provide unstructured qualitative feedback. Irrespective of whether the activity is carried out in a laboratory, in a high fidelity simulation or in a naturalistic setting, participants will frequently volunteer unsolicited feedback about tasks and goals that were not originally within the ambit of the design activity. This unprompted feedback, we suggest, is a cue for the evaluators to pay attention to the relationship between the tool and the practice in which it will be used. In other words a cue to consider the situations in which artefact will be used, the tasks and activities that may be affected by the new system, and so on. These are empirical questions that cannot be answered a priori by the development team, whether the evaluation is taking place in “artificial” or “natural” setting

    Evaluating combined 2D/3D displays for ATC.

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    Comment On ``Grand Unification and Supersymmetric Threshold"

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    Barbieri and Hall have argued that threshold effects at the scale of grand-unification wipe out predictions on the SUSY scale, M_S. Using triviality arguments we give upper bounds on ultraheavy particles, while proton stability gives lower bounds on the mass of the higgs color-triplet. We find no useful lower bound on the ÎŁ\Sigma supermultiplet, but if the strong coupling constant is as large as recent experiments suggest, unification in the minimal SUSY SU(5) model requires that the SigmaSigma masses be ∌10−7MV\sim 10^{-7}M_V and that the color octet and weak triplet be split in mass by a factor of ∌\sim100.Comment: 6 pages (revised

    High-power test results of a 3 GHz single-cell cavity

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    Compact, reliable and little consuming accelerators are required for the treatment of tumours with ions. TERA proposes the "cyclinac", composed of a high-frequency, fast-cycling linac which boosts the energy of the particles previously accelerated in a cyclotron. The dimensions of the linac can be reduced if high gradients are used. TERA initiated a high-gradient test program to understand the operational limit of such structures. The program foresees the design, prototyping and high-power test of several high-gradient structures operating at 3 and 5.7 GHz. The high-power tests of the 3 GHz single-cell cavity were completed in Winter 2012. The maximum BDR threshold measured for Emax of 170 MV/m and RF pulses of 2.5 \mu s was 3 x 10-6 bpp/m

    Phenomenological Analysis of pppp and pˉp\bar{p}p Elastic Scattering Data in the Impact Parameter Space

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    We use an almost model-independent analytical parameterization for pppp and pˉp\bar{p}p elastic scattering data to analyze the eikonal, profile, and inelastic overlap functions in the impact parameter space. Error propagation in the fit parameters allows estimations of uncertainty regions, improving the geometrical description of the hadron-hadron interaction. Several predictions are shown and, in particular, the prediction for pppp inelastic overlap function at s=14\sqrt{s}=14 TeV shows the saturation of the Froissart-Martin bound at LHC energies.Comment: 15 pages, 16 figure

    Neutrino masses and flavor symmetries

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    The problem of neutrino masses and mixing angles is analysed in a class of supersymmetric grand unified models, with SO(10) gauge symmetry and global U(2) flavour symmetry. Adopting the seesaw mechanism for the generation of the neutrino masses, one obtains a mass matrix for the left-handed neutrinos which is directly related to the parameters of the charged sector, while the unknown parameters of the right-handed Majorana mass matrix are inglobed in a single factor.Comment: 17 pages, 1 eps figure, uses graphicx.sty, LaTeX 2e, to be published on "Il Nuovo Cimento

    On Upper Limits for Gravitational Radiation

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    A procedure with a Bayesan approach for calculating upper limits to gravitational wave bursts from coincidence experiments with multiple detectors is described.Comment: 10 pages, 2 figures, latex files using cernlik.cls (included). This paper and related work are also available at http://grwav3.roma1.infn.it/pia/papersweb.html Version number 2: text unchanged. Modified two references, adding the hep number

    What do experimental data "say" about growth of hadronic total cross-section?

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    We reanalyse pˉp\bar p p and pppp high energy data of the elastic scattering above s=5\sqrt{s}=5 GeV on the total cross-section σtot\sigma_{tot} and on the forward ρ\rho-ratio for various models of Pomeron, utilizing two methods. The first one is based on analytic amplitudes, the other one relies on assumptions for σtot\sigma_{tot} and on dispersion relation for ρ\rho. We argue that it is not possible, from fitting only existing data for forward scattering, to select a definite asymptotic growth with the energy of σtot\sigma_{tot}. We find equivalent fits to the data together with a logarithmic Pomeron giving a behavior σtot∝ln⁥γs\sigma_{tot} \propto \ln ^\gamma s, γ∈[0.5,2.20]\gamma\in [0.5,2.20] and with a supercritical Pomeron giving a behavior σtot∝sÏ”\sigma_{tot} \propto s^\epsilon , ϔ∈[0.01,0.10]\epsilon\in [0.01,0.10].Comment: LaTeX, 18 pages, 5 eps figures included, to be published in Il Nuovo Ciment

    3D-in-2D Displays for ATC.

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    This paper reports on the efforts and accomplishments of the 3D-in-2D Displays for ATC project at the end of Year 1. We describe the invention of 10 novel 3D/2D visualisations that were mostly implemented in the Augmented Reality ARToolkit. These prototype implementations of visualisation and interaction elements can be viewed on the accompanying video. We have identified six candidate design concepts which we will further research and develop. These designs correspond with the early feasibility studies stage of maturity as defined by the NASA Technology Readiness Level framework. We developed the Combination Display Framework from a review of the literature, and used it for analysing display designs in terms of display technique used and how they are combined. The insights we gained from this framework then guided our inventions and the human-centered innovation process we use to iteratively invent. Our designs are based on an understanding of user work practices. We also developed a simple ATC simulator that we used for rapid experimentation and evaluation of design ideas. We expect that if this project continues, the effort in Year 2 and 3 will be focus on maturing the concepts and employment in a operational laboratory settings
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