6,364 research outputs found

    Natural Supersymmetry, Muon g2g-2, and the Last Crevices for the Top Squark

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    We study the interplay of natural supersymmetry and a supersymmetric solution to the discrepancy observed in measurements of the muon magnetic moment. The strongest constraints on the parameter space currently come from chargino searches in the trilepton channel and slepton searches in the dilepton channel at the LHC, and vast regions are currently allowed, especially at large tanβ\tan{\beta}. With light top squarks in the spectrum, as required from naturalness arguments, the situation changes dramatically; stop-assisted chargino and neutralino production via t~bχ~1±\tilde{t} \rightarrow b \tilde{\chi}_{1}^{\pm} and t~tχ~10\tilde{t} \rightarrow t \tilde{\chi}_{1}^0 are already probing the entire parameter space compatible with the muon magnetic moment at tanβO(10)\tan{\beta} \sim \mathcal{O}(10), while upcoming stop searches will probe most of the parameter space at larger tanβ40\tan{\beta} \sim 40. Direct Higgsino searches as well as compressed slepton and stop searches are crucial to close out corners of parameter space. We consider one such example: in the presence of light sleptons and charginos as required to obtain appreciable contributions to the muon magnetic moment, compressed stops can dominantly undergo the following decay t~b~ν(ν~)bνχ~10\tilde{t} \, \rightarrow \, b \tilde{\ell} \nu (\tilde{\nu} \ell) \, \rightarrow \, b \ell \nu \tilde{\chi}_{1}^0, facilitated by off-shell charginos. We find that the enhanced branching to leptons leads to a 5σ5 \sigma mass reach (with 30003000 fb1^{-1} of data at LHC14) of mt~350m_{\tilde{t}} \, \sim \, 350 GeV, with the mass difference between stops and the lightest neutralino being 80\sim 80 GeV. This will further close out a significant part of the parameter space compatible with naturalness and the muon magnetic moment.Comment: 13 pages, 14 figures. Matches published versio

    Radiation Testing of Electronics for the CMS Endcap Muon System

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    The electronics used in the data readout and triggering system for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) particle accelerator at CERN are exposed to high radiation levels. This radiation can cause permanent damage to the electronic circuitry, as well as temporary effects such as data corruption induced by Single Event Upsets. Once the High Luminosity LHC (HL-LHC) accelerator upgrades are completed it will have five times higher instantaneous luminosity than LHC, allowing for detection of rare physics processes, new particles and interactions. Tests have been performed to determine the effects of radiation on the electronic components to be used for the Endcap Muon electronics project currently being designed for installation in the CMS experiment in 2013. During these tests the digital components on the test boards were operating with active data readout while being irradiated with 55 MeV protons. In reactor tests, components were exposed to 30 years equivalent levels of neutron radiation expected at the HL-LHC. The highest total ionizing dose (TID) for the muon system is expected at the inner-most portion of the CMS detector, with 8900 rad over ten years. Our results show that Commercial Off-The-Shelf (COTS) components selected for the new electronics will operate reliably in the CMS radiation environment

    Angular analysis and branching fraction measurement of the decay B0→K*0μ+μ−

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    The angular distributions and the differential branching fraction of the decay B0→K*(892)0μ+μ− are studied using a data sample corresponding to an integrated luminosity of 5.2 fb−1collected with the CMS detector at the LHC in pp collisions at √s=7 TeV. From more than 400 signal decays, the forward–backward asymmetry of the muons, the K*(892)0 longitudinal polarization fraction, and the differential branching fraction are determined as a function of the square of the dimuon invariant mass. The measurements are in good agreement with standard model predictions

    Patients’ narratives of surgical site infection: implications for practice

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    Background Exploring patients' experiences has been used widely within healthcare to improve clinical service delivery. To date there has been minimal patient input of this kind into aspects of surgical site infection (SSI), such as surveillance or prevention interventions. Aim To obtain information from patients' experiences of SSIs to improve clinical practice. Methods Narrative interviews with 17 patients with SSIs (four deep, 12 organ space and one superficial) from three hospitals in England were conducted followed by thematic content analysis. Results Patients lacked overall awareness, concern and understanding of SSIs. Seven patients did not know that they had SSIs and, judging from patients' accounts, staff may have contributed to the lack of awareness by not informing patients of SSIs or downplaying their existence. The use of primary care resources was considerable and six of the patients were absent from work for two to four months. Conclusions SSIs have a low profile among patients which, if it were raised, could increase compliance with preventive interventions. This study confirms the appropriateness of using patient self-assessment post-discharge surveillance questionnaires to identify SSI symptoms, and highlights the need to identify total costings including to primary care, patients and the economy

    Essential requirements for setting up a stem cell processing laboratory

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    The Graft Processing subcommittee of the Worldwide Network for Blood and Marrow Transplantation wrote this guideline to assist physicians and laboratory technologists with the setting up of a cell processing laboratory (CPL) to support a hematopoietic stem cell transplant program, thereby facilitating the start-up of a transplant program in a new location and improving patient access to transplantation worldwide. This guideline describes the minimal essential features of designing such a laboratory and provides a list of equipment and supply needs and staffing recommendations. It describes the typical scope of services that a CPL is expected to perform, including product testing services, and discusses the basic principles behind the most frequent procedures. Quality management (QM) principles specific to a CPL are also discussed. References to additional guidance documents that are available worldwide to assist with QM and regulatory compliance are also provided. © 2014 Macmillan Publishers Limited All rights reserved

    Search for electroweak production of charginos and neutralinos in WH events in proton-proton collisions at s√=13 TeV

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    Results are reported from a search for physics beyond the standard model in proton-proton collision events with a charged lepton (electron or muon), two jets identified as originating from a bottom quark decay, and significant imbalance in the transverse momentum. The search was performed using a data sample corresponding to 35.9 fb−1, collected by the CMS experiment in 2016 at s√=13 TeV. Events with this signature can arise, for example, from the electroweak production of gauginos, which are predicted in models based on supersymmetry. The event yields observed in data are consistent with the estimated standard model backgrounds. Limits are obtained on the cross sections for chargino-neutralino (χ~±1χ~02) production in a simplified model of supersymmetry with the decays χ±1→W±χ~01andχ~02→Hχ01. Values of mχ~±1 between 220 and 490 GeV are excluded at 95% confidence level by this search when the χ~01 is massless, and values of mχ~01 are 1 excluded up to 110 GeV for mχ~±1≈450 GeV
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