775 research outputs found

    Exotic Quark Production in ep Collisions

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    We investigate the single production and decay of charge -1/3, weak isosinglet vectorlike exotic DD quarks in string inspired E6E_6 theories at future ep colliders; THERA with s\sqrt s=1 TeV, L=40 pb−1pb^{-1} and CERN Large Hadron Electron Collider (LHeC) with s\sqrt s=1.4 TeV, L=104L=10^4 pb−1pb^{-1}. We found that an analysis of the decay modes of DD should probe the mass ranges of 100-450 GeV and 100-1200 GeV at the center of mass energies, 1 and 1.4 TeV, respectively.Comment: 13 pages,8 figure

    Single and pair production of heavy leptons in E6E_6 model

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    We investigate the single and pair production of new heavy leptons via string inspired E6E_{6} model at future linear colliders. Signal and corresponding backgrounds for these leptons are studied. We have found that single production of heavy leptons is more relevant than that of pair production, as expected. For a maximal mixing value of 0.1, the upper mass limits of 2750 GeV in the single case and 1250 GeV in the pair production case are obtained at s=3\sqrt{s}=3 TeV collider option.Comment: 14 pages, 10 figure

    Removal and Reoccurrence of LLZTO Surface Contaminants under Glovebox Conditions

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    The reactivity of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) solid electrolytes to form lithio-phobic species such as Li2CO3 on their surface when exposed to trace amounts of H2O and CO2 limits the progress of LLZTO-based solid-state batteries. Various treatments, such as annealing LLZTO within a glovebox or acid etching, aim at removing the surface contaminants, but a comprehensive understanding of the evolving LLZTO surface chemistry during and after these treatments is lacking. Here, glovebox-like H2O and CO2 conditions were recreated in a near ambient pressure X-ray photoelectron spectroscopy chamber to analyze the LLZTO surface under realistic conditions. We find that annealing LLZTO at 600 °C in this atmosphere effectively removes the surface contaminants, but a significant level of contamination reappears upon cooling down. In contrast, HCl(aq) acid etching demonstrates superior Li2CO3 removal and stable surface chemistry post treatment. To avoid air exposure during the acid treatment, an anhydrous HCl solution in diethyl ether was used directly within the glovebox. This novel acid etching strategy delivers the lowest lithium/LLZTO interfacial resistance and the highest critical current density

    Factors Affecting the Outcome in Traumatic Subarachnoid Hemorrhage

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    Objective: To define risk factors affecting the outcome in traumatic subarachnoid hemorrhage.Material and Methods: Forty-four patients with traumatic subarachnoid hemorrhage were evaluated retrospectively. They were divided into three groups according to their age: elderly (≥65 years), adult (16- 64 years), and children (<16 years). The clinical picture on admission was evaluated using the Glasgow Coma Scale. The patients were also divided into three groups according to their coma grading on admission: mild injury (Glasgow Coma Scale score 13-15), moderate injury (8-12), and severe injury (3-7). The amount of subarachnoid blood shown in computerized tomography was evaluated according to the Fisher index, and additional tomography findings were recorded. At last follow-up, presence of headache and neurological deficits as well as return to work or school were investigated, and the last clinical picture was evaluated with the Glasgow Outcome Scale.Results: There were 11 children, 23 adults and 10 elderly patients. Twelve patients died between 1-49 days after trauma; the others were followed for a mean of 14.6 months (from 10 to 30 months). In the children group, Glasgow Coma Scale score was significantly higher (p=0.004), subarachnoid blood amount was significantly lesser, and Glasgow Outcome Scale score was significantly better compared to the other groups. For all groups, higher trauma severity on admission was associated with higher Fisher index (p=0.016). Most important factors affecting clinical results were severity of head injury on admission (p=0.0001), Fisher index (p=0.003), and presence of additional findings on computerized tomography (p=0.0001).Conclusion: Traumatic subarachnoid hemorrhage usually has a good clinical outcome in children; however, in elderly patients, the outcome is worse, and there are usually additional intracranial traumatic lesions. Most important factors affecting outcome are blood amount on first computerized tomography, head trauma severity, and presence of additional intracranial traumatic lesions

    Poor prognostic clinicopathologic features correlate with VEGF expression but not with PTEN expression in squamous cell carcinoma of the larynx

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to assess the relationship between expression of vascular endothelial growth factor (VEGF) and phosphatase and tensin homolog deleted in chromosome ten (PTEN), angiogenesis and clinicopathological parameters of squamous cell carcinoma of the larynx.</p> <p>Methods</p> <p>We examined immunohistochemical expression of VEGF and PTEN and CD34 for microvessel density (MVD) in sections of formalin-fixed, paraffin embedded tissue blocks of 140 patients with squamous cell carcinoma of the larynx. The intensity of VEGF and PTEN staining and the proportion of cells staining were scored.</p> <p>Results</p> <p>The tumor grade was not significantly related to PTEN expression, but it was to VEGF expression (p = 0.400; p = 0.015, respectively). While there was no significant relationship between PTEN expression and tumor size and cartilage invasion (p = 0.311, p = 0.128), there was a significant relationship between the severity of VEGF expression and tumor size (p = 0.006) and lymph node metastasis (p = 0.048) but not cartilage invasion (p = 0.129). MVD was significantly higher in high-grade tumors (p = 0.003) but had no significant relationship between MVD, lymph node metastasis, and cartilage invasion (p = 0.815, p = 0.204). There was also no significant relationship between PTEN and VEGF expression (p = 0.161) and between PTEN and VEGF expression and the MVD (p = 0.120 and p = 0.175, respectively).</p> <p>Conclusions</p> <p>Increased VEGF expression may play an important role in the outcome of squamous cell carcinoma of the larynx. PTEN expression was not related to VEGF expression and clinicopathological features of squamous cell carcinoma of the larynx.</p

    Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV

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    We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1 sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to figures and updated and expanded reference

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Top quark mass measurement using the template method at CDF

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    We present a measurement of the top quark mass in the lepton+jets and dilepton channels of ttˉt\bar{t} decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb−1^{-1} of ppˉp\bar{p} collisions at Tevatron with s=1.96\sqrt{s}=1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the WW decay in the lepton+jets channel, and a reconstructed top quark mass and mT2m_{T2}, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop=172.1±1.1(stat)±0.9(syst).M_{top} = 172.1 \pm 1.1(stat) \pm 0.9(syst).Comment: submitted to Phys. Rev.

    Standalone vertex nding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011
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