20,179 research outputs found

    Dirac Gauginos in Supersymmetry -- Suppressed Jets + MET Signals: A Snowmass Whitepaper

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    We consider the modifications to squark production in the presence of a naturally heavier Dirac gluino. First generation squark production is highly suppressed, providing an interesting but challenging signal find or rule out. No dedicated searches for supersymmetry with a Dirac gluino have been performed, however a reinterpretation of a "decoupled gluino" simplified model suggests the bounds on a common first and second generation squark mass is much smaller than in the MSSM: \lsim 850 GeV for a massless LSP, and no bound for an LSP heavier than about 300 GeV. We compare and contrast the squark production cross sections between a model with a Dirac gluino and one with a Majorana gluino, updating earlier results in the literature to a pppp collider operating at s=14\sqrt{s} = 14 and 33 TeV. Associated production of squark+gluino is likely very small at s=14\sqrt{s} = 14 TeV, while is a challenging but important signal at even higher energy pppp colliders. Several other salient implications of Dirac gauginos are mentioned, with some thought-provoking discussion as it regards the importance of the various experiments planned or proposed.Comment: 10 pages, 6 figures; this Snowmass Whitepaper has been submitted to arXiv at the request of the Snowmass convener

    Face masks for the public during Covid-19: an appeal for caution in policy

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    As the Covid-19 crisis deepens, some researchers have argued for the widespread routine use of face masks in community settings, despite acknowledged gaps in the evidence base for the effectiveness of such a measure. We argue that such calls are premature, and risk neglecting important potential harms and negative consequences, known and unknown. We identify potential unintended consequences at multiple levels, from individual-behavioural to macrosocial, and suggest that it is far from clear that the benefits of widespread uptake of face masks, whether encouraged or enforced by public authorities, outweigh the downsides. Finally, we make the case for caution in communicating unequivocal messages about the scientific evidence for face mask use to policy, practitioner and public audiences, given continued scientific disagreement on the questio

    More than a Match: The Role of Football in Britain’s Deaf Community

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    The University of Central Lancashire has undertaken a major research project into the role of football within the deaf community in Britain. As well as reconstructing the long history of deaf involvement in football for the first time, the project has also focused on the way in which football has provided deaf people with a means of developing and maintaining social contacts within the community, and of expressing the community’s cultural values. This article will draw on primary data gathered from interviews conducted with people involved in deaf football in a variety of capacities. During the course of these interviews, a number of themes and issues emerged relating to the values and benefits those involved with deaf football place on the game, and it is these which are explored here

    Shareholder Voting and Directors’ Remuneration Report Legislation: Say on Pay in the U.K. (CRI 2009-004)

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    This paper investigates shareholder voting in the UK. The Directors’ Remuneration Report (DRR) Regulations of 2002 gave shareholders a mandatory non-binding vote on boardroom pay. First, using data on about 50,000 resolutions over the period 2002 to 2007 we find that less than 10% of shareholders abstain or vote against the mandated Directors’ Remuneration Report (DRR) resolution. Second, investors are more likely to vote against DRR resolutions compared to non-pay resolutions. Third, shareholders are more likely to vote against general executive pay resolutions, such as stock options, long term incentive plans and bonus resolutions compared to non-pay resolutions. Forth, firms with higher CEO pay attract greater voting dissent. Fifth, there is little evidence that CEO pay is lower in firms that previously experienced high levels of shareholder dissent. In addition, there is little evidence that the equity pay-mix, representing better owner-manager alignment, is greater in such firms. Currently, we find limited evidence that, on average, ‘say on pay’ materially alters the subsequent level and design of CEO compensation

    Natural Supersymmetry and Implications for Higgs physics

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    We re-analyze the LHC bounds on light third generation squarks in Natural Supersymmetry, where the sparticles have masses inversely proportional to their leading-log contributions to the electroweak symmetry breaking scale. Higgsinos are the lightest supersymmetric particles; top and bottom squarks are the next-to-lightest sparticles that decay into both neutral and charged Higgsinos with well-defined branching ratios determined by Yukawa couplings and kinematics. The Higgsinos are nearly degenerate in mass, once the bino and wino masses are taken to their natural (heavy) values. We consider three scenarios for the stop and sbottom masses: (I) t~R\tilde{t}_R is light, (II) t~L\tilde{t}_L and b~L\tilde{b}_L are light, and (III) t~R\tilde{t}_R, t~L\tilde{t}_L, and b~L\tilde{b}_L are light. Dedicated stop searches are currently sensitive to Scenarios II and III, but not Scenario I. Sbottom-motivated searches (2b+MET2 b + \rm{MET}) impact both squark flavors due to \tilde{t} \ra b \charp_1 as well as \tilde{b} \ra b \neut_{1,2}, constraining Scenarios I and III with somewhat weaker constraints on Scenario II. The totality of these searches yield relatively strong constraints on Natural Supersymmetry. Two regions that remain are: (1) the "compressed wedge", where (mq~μ)/mq~1(m_{\tilde{q}} - |\mu|)/m_{\tilde{q}} \ll 1, and (2) the "kinematic limit" region, where m_{\tilde{q}} \gsim 600-750 GeV, at the kinematic limit of the LHC searches. We calculate the correlated predictions for Higgs physics, demonstrating that these regions lead to distinct predictions for the lightest Higgs couplings that are separable with \simeq 10% measurements. We show that these conclusions remain largely unchanged once the MSSM is extended to the NMSSM in order to naturally obtain a large enough mass for the lightest Higgs boson consistent with LHC data.Comment: 18 pages, 8 figure
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