767,761 research outputs found

    Same-sign top quarks as signature of light stops at the LHC

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    We present a new method to search for a light scalar top with m_{\tilde{t}_1}\lsim m_t, decaying dominantly into a c-jet and the lightest neutralino, at the LHC. The principal idea is to exploit the Majorana nature of the gluino, leading to same-sign top quarks in events of gluino-pair production followed by gluino decays into top and stop. The resulting signature is 2 b-jets plus 2 same-sign leptons plus additional jets and missing energy. We perform a Monte Carlo simulation for a benchmark scenario, which is in agreement with the recent WMAP bound on the relic density of dark matter, and demonstrate that for m_{\tilde{g}}\lsim 900 GeV and mq~>mg~m_{\tilde{q}}>m_{\tilde{g}} the signal can be extracted from the background. Moreover, we discuss the determination of the stop and gluino masses from the shape of invariant-mass distributions. The derivation of the shape formulae is also given.We present a new method to search for a light scalar top with m_{\tilde{t}_1}\lsim m_t, decaying dominantly into a c-jet and the lightest neutralino, at the LHC. The principal idea is to exploit the Majorana nature of the gluino, leading to same-sign top quarks in events of gluino-pair production followed by gluino decays into top and stop. The resulting signature is 2 b-jets plus 2 same-sign leptons plus additional jets and missing energy. We perform a Monte Carlo simulation for a benchmark scenario, which is in agreement with the recent WMAP bound on the relic density of dark matter, and demonstrate that for m_{\tilde{g}}\lsim 900 GeV and mq~>mg~m_{\tilde{q}}>m_{\tilde{g}} the signal can be extracted from the background. Moreover, we discuss the determination of the stop and gluino masses from the shape of invariant-mass distributions. The derivation of the shape formulae is also given

    (Re)interpretation of the LHC results for new physics

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    ColliderBit is the GAMBIT module responsible for simulating LHC physics in the GAMBIT global fitting tool. In this talk we will present recent technical developments in ColliderBit, including new LHC analysis implemented, improvements to three-body decay kinematics relevant for supersymmetry searches, as well as updates to interfaces to other codes

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Dispelling the Myths Behind First-author Citation Counts

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    We conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more sophisticated methods

    Interpreting a CMS excess in lljj+ missing -transverse-momentum with the golden cascade of the minimal supersymmetric standard model

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    CMS recently reported an excess consistent with an invariant mass edge in opposite-sign same flavor (OSSF) leptons, when produced in conjunction with at least two jets and missing transverse momentum. We provide an interpretation of the edge in terms of (anti-)squark pair production followed by the `golden cascade' decay for one of the squarks: q~χ~20ql~lqχ~10qll\tilde q \rightarrow \tilde\chi_2^0 q \to \tilde l l q \to \tilde\chi_1^0 q l l in the minimal supersymmetric standard model (MSSM). A simplified model involving binos, winos, an on-shell slepton, and the first two generations of squarks fits the event rate and the invariant mass edge while passing current collider constraints. We present the good-fit parameter space of the model, along with squark production predictions for LHC Run II conducted at 13 TeV centre of mass energy. Portions of the good-fit parameter space also predict a thermal relic density of neutralino dark matter (Ωh2)(\Omega h^2) compatible with cosmological observations, and an anomalous magnetic moment of the muon (g2)μ(g-2)_\mu compatible with measurements

    The vanishing author in computer-generated works: a critical analysis of recent Australian case law

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    Abstract The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals

    Alternative formation model for antideuterons from dark matter

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    Antideuterons are a potential messenger for dark matter annihilation or decay in our own Galaxy, with very low backgrounds expected from astrophysical processes. The standard coalescence model of antideuteron formation, while simple to implement, is shown to be under considerable strain by recent data from the LHC. We suggest a new empirically based model, with only one free parameter, which is better able to cope with these data, and we explore the consequences of the model for dark matter searches. © 2015 American Physical Societ

    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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