3,410 research outputs found

    Higgs Boson Discovery and Properties

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    We outline issues examined and progress made by the Light Higgs Snowmass 1996 working group regarding discovering Higgs bosons and measuring their detailed properties. We focused primarily on what could be learned at LEP2, the Tevatron (after upgrade), the LHC, a next linear \epem collider and a \mupmum collider.Comment: 47 pages, full postscript file also available via anonymous ftp at ftp://ucdhep.ucdavis.edu/gunion/summary_snowmass96.ps To appear in ``Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics''. Minor revisions of references and wording have been made in a few place

    Renal Stone Formation in Patients with Inflammatory Bowel Disease

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    Kidney stones are more common in patients with inflammatory bowel disease (IBD) than in the general population. The main lithogenetic risk factors were evaluated in patients affected by Crohn\u27s disease and ulcerative colitis. Our results show the presence of several factors, besides hyperoxaluria, in patients with IBD although their behaviour appears different in Crohn\u27s disease and ulcerative colitis at pre- and post-operative stages. Before surgery in patients with Crohn\u27s disease we found a decreased citrate (p \u3c 0.001) and magnesium (p \u3c 0.005) excretion together with a low urinary volume (p \u3c 0.001) and pH (p \u3c 0.005). After surgery patients with Crohn\u27s disease showed a further reduction of magnesium and citrate. Patients with ulcerative colitis before surgery showed a reduced citrate excretion (p \u3c 0.05) and a more acidic pH (p \u3c 0.05) than healthy subjects. Surgical treatment of proctocolectomy with ileal pouch-anal anastomosis seems to increase the risk of stone formation; in fact, after surgery we observed a relevant decrease of urinary volume (p \u3c 0.001), pH (p \u3c 0.0001) and urinary excretion of citrate (p \u3c0.0001) as well as magnesium (p \u3c 0.005). Patients with IBD seem to be at greater risk of stone formation than patients with idiopathic calcium lithiasis; in fact, they show a lower excretion of citrate (p \u3c 0.001) and magnesium (p \u3c 0.001) together with a low urinary pH (p \u3c 0.001) and volume (p \u3c 0.001). Urinary volume reduction is probably one of the major risk factors together with the decrease of small molecular weight inhibitors that is a constant finding in all patients with IBD

    Infliximab in the treatment of Crohn's disease

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    The recent introduction of infliximab, a chimeric monoclonal antibody against tumor necrosis factor-alpha, has greatly modified the treatment of Crohn's disease (CD). Data from the literature show encouraging results after intravenous infusion both for closure of intestinal or perianal fistulas and for induction and maintenance of remission in patients with moderate to severe intestinal disease unresponsive to other treatments. However, some contraindications such as fibrostenosing CD and sepsis have been identified. In addition, the data on long-term outcomes and safety is still limited. Our initial experience showed that in selected cases local injection of infliximab is effective in the treatment of complex perianal disease offering the possibility of using such treatment even in small bowel obstructing disease with minimal systemic effects. This paper analyzes the state of the use of both intravenous and local injection of infliximab in patients with CD

    User Requirements and User Strategy in the AWARE Project

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    Abstract AWARE (A tool for monitoring and forecasting Available WAter REsource in mountain environment) is a Project in the VI Framework Programme of European Community. It started in July 2005 and aims at offering methods and tools to monitor and forecast the water resource from Alpine snowmelt by hydrologic models using input data derived from both in situ observations and Earth Observations (EO). In order to reach its objectives, AWARE needs strength collaboration with users. To this purpose activities to raise users' interests, to meet users' expectations and to spread Project achievements are planned. This paper describes the strategy used to collect user requirements within AWARE and illustrates some results of the user requirements analysis

    Dimensionless Coupling of Bulk Scalars at the LHC

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    We identify the lowest-dimension interaction which is possible between Standard Model brane fields and bulk scalars in 6 dimensions. The lowest-dimension interaction is unique and involves a trilinear coupling between the Standard Model Higgs and the bulk scalar. Because this interaction has a dimensionless coupling, it depends only logarithmically on ultraviolet mass scales and heavy physics need not decouple from it. We compute its influence on Higgs physics at ATLAS and identify how large a coupling can be detected at the LHC. Besides providing a potentially interesting signal in Higgs searches, such couplings provide a major observational constraint on 6D large-extra-dimensional models with scalars in the bulk.Comment: 20 page

    Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

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    A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

    Position resolution and particle identification with the ATLAS EM calorimeter

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    In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

    Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method

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    This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known e/he/h ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within ±1\pm 1% of the true values and the fractional energy resolution is [(58±3)/E+(2.5±0.3)[(58\pm3)% /\sqrt{E}+(2.5\pm0.3)%]\oplus (1.7\pm0.2)/E. The value of the e/he/h ratio obtained for the electromagnetic compartment of the combined calorimeter is 1.74±0.041.74\pm0.04 and agrees with the prediction that e/h>1.7e/h > 1.7 for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13