59 research outputs found

    Tagging b jets with electrons and muons at CMS

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    The first results of identification of jets from b quarks with soft-lepton tagging algorithms are presented in this note. Jets are built from the energy deposits in the electromagnetic and hadron calorimeters, with an iterative cone algorithm. Electrons and muons are searched for among the reconstructed charged particle tracks associated to these jets with an angular distance criterion. The muon identification is based on standard muon reconstruction algorithms, exploiting the dedicated muon detectors, while electron identification is based on the extrapolation of charged particle tracks into the calorimeter and a detailed analysis of the calorimeter clusters in the region around the track. Jets from b quarks are identified from the kinematic properties of the leptons relative to the jet and the significance of the three dimensional impact parameter of the lepton with respect to the event vertex. The effect of not incorporating the impact parameter significance, as would be necessary for data collected prior to the installation of the silicon pixel tracking detector, is also studied

    Assessment of long-term changes in the surface air temperature from the High Arctic archipelago Franz Joseph Land from 1929 to the present (2017)

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    Electronicarchivesof datafromstandard meteorological observations(mean daily/monthly surface air temperatures - SAT)at the meteorological stations at Bukhta Tikhaya (Hooker Island, 1929-1960) and Krenkel Observatory (Hayes Island, 1957-2017) on Franz Josef Land (FJL) are presented. Parallel data series of SAT made in 1958 and 1959 on both meteorological stations were analyzed. Linear regression equations used for extrapolation of observational data representative for Krenkel Observatory for the period 1929-1957 are also presented. The assessment of long-term changes in SAT on FJL was carried out based on the analysis of the obtained series (1929-2017). The main conclusions that follow from our study are: (1) The total warming in the FJL archipelago was 1.6-1.8°C (0.2°C/decade) for the entire available period of instrumental observations (1929-2017); (2) The highest rates of warming were recorded in March-April and amounted to 0.6°C/decade; (3) A particular strong warming has been observed since the 1990s. The annual temperature increased by 6.3°C (2.2°C/decade) for the period 1990-2017 and 5.2°C (2.9°C/decade) for the period 2000-2017; (4) For the period 1990-2017 the maximum rate of warming occurred between October to February with 4.4°C/decade; (5) For the period 2000-2017 the maximum rate of warming occurred between January to April and from November to December with 5.6°C/decade; (6) The dominant seasons of the year are winter (November-April), spring (May), summer (June-September) and autumn (October); (7) Over the entire observation period the largest temperature increase was observed in the winter season. During the period of modern warming (1990-2017), the largest temperature increase was observed in winter and autumn.

    Corruption on the Finnish-Russian Border: Experiences and observations of Finnish and Russian civil servants and businesspersons on corruption on the border between Finland and Russia

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    This research project was carried out on the initiative of the Finnish Ministry of Justice. Its objective has been to provide the relevant authorities with new and better knowledge regarding corruption on the Finnish-Russian border. The results can also be used as working material at joint seminars and training events. This is expected to facilitate constructive debate between the authorities of both countries, based on more concrete observations than what has been available previously

    Portable Resistive Plate Chambers for Muography in confined environments

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    Muography (or muon radiography) is an imaging technique that relies on the use of cosmogenic muons as a free and safe radiation source. It can be applied in various fields such as archaeology, civil engineering, geology, nuclear reactor monitoring, nuclear waste characterization, underground surveys, etc. In such applications, sometimes deploying muon detectors is challenging due to logistics, e.g. in a narrow underground tunnel or mine. Therefore, we are developing muon detectors whose design goals include portability, robustness, autonomy, versatility, and safety. Our portable muon detectors (or ``muoscopes'') are based on Resistive Plate Chambers (RPC), planar detectors that use ionization in a thin gas gap to detect cosmic muons. Prototype RPCs of active area 16×16 cm216 \times 16~cm^2 and 28×28 cm228 \times 28~cm^2 were built in our laboratories at Louvain-la-Neuve (UCLouvain) and Ghent (UGent) to test and compare various design options. Benefiting from the experience gained in building and operating these prototypes, we are proceeding towards the development of improved prototypes with more advanced technical layout and readiness. In this paper we provide the status of our performance studies, including the cross-validation of the two types of prototypes in a joint data taking, and an outline of the direction ahead

    Small-area Portable Resistive Plate Chambers for Muography

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    Muography is finding applications in various domains such as volcanology, archaeology, civil engineering, industry, mining, and nuclear waste surveys. To simplify transportation and installation in remote locations after laboratory testing, a fully portable and autonomous muon telescope based on Resistive Plate Chambers (RPCs) is being developed. Two glass-RPC prototypes have been created, sharing the same design goals but with different detector parameters, and comparative studies are ongoing. Drawing from prototype experience, a double-gap RPC with advanced features and improved spatial resolution is constructed. Resistive electrodes are produced manually, and a new data acquisition board is currently undergoing calibration. The results on prototype performance, readout board comparisons and the technical progress on the double-gap RPC are presented

    MadGraph/MadEvent v4: The New Web Generation

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    We present the latest developments of the MadGraph/MadEvent Monte Carlo event generator and several applications to hadron collider physics. In the current version events at the parton, hadron and detector level can be generated directly from a web interface, for arbitrary processes in the Standard Model and in several physics scenarios beyond it (HEFT, MSSM, 2HDM). The most important additions are: a new framework for implementing user-defined new physics models; a standalone running mode for creating and testing matrix elements; generation of events corresponding to different processes, such as signal(s) and backgrounds, in the same run; two platforms for data analysis, where events are accessible at the parton, hadron and detector level; and the generation of inclusive multi-jet samples by combining parton-level events with parton showers. To illustrate the new capabilities of the package some applications to hadron collider physics are presented: 1) Higgs search in pp \to H \to W^+W^-: signal and backgrounds. 2) Higgs CP properties: pp \to H jj$in the HEFT. 3) Spin of a new resonance from lepton angular distributions. 4) Single-top and Higgs associated production in a generic 2HDM. 5) Comparison of strong SUSY pair production at the SPS points. 6) Inclusive W+jets matched samples: comparison with the Tevatron data.Comment: 38 pages, 15 figure

    Numerical solution of photocounting statistics inverse problem for few-photon pulsed laser sources

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    We present a numerical procedure for recovering of photon statistics of few-photon pulsed laser sources. It provides controlled level of mean error for both of photon and photocounting statistics. It is shown that procedure is correct for model data with average error level of 10−4 and fidelity 0.9998

    Bicyclo[4.2.0]octa-1,3,5-trien-3-yl-dimethyl((E)-styryl)-silane

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    Bicyclo[4.2.0]octa-1,3,5-trien-3-yl-dimethyl-((E)-styryl)-silane was synthesized via three stage synthesis starting from benzocyclobutene and (2-bromo-vinyl)-benzene. The structure of the product was determined using 1H- and 13C-NMR and HRMS
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