2,823 research outputs found

    Search for f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay with VES detector

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    The isospin violating decay f1(1285)π+ππ0f_1(1285)\to\pi^+\pi^-\pi^0 has been studied at VES facility. This study is based at the statistics acquired in πBe\pi^- Be interactions at 27, 36.6 and 41 GeV/c in diffractive reaction πN(f1π)N\pi^- N \to (f_1 \pi^-) N. The f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay is observed. The ratio of decay probabilities BR(f1(1285)π+ππ0)BR(f_1(1285) \to \pi^+\pi^-\pi^0) to BR(f1(1285)ηπ+π)BR(ηγγ)BR(f_1(1285) \to \eta \pi^+\pi^-) \cdot BR(\eta \to \gamma\gamma) is 1.4\sim\:1.4%.Comment: 10 pages, 8 figures, presented at XII Conference on Hadron Spectroscop

    Electroweak diboson production at ATLAS

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    This paper is giving an overview of recent ATLAS results on the production cross sections of gauge boson pairs decaying leptonically using data from pp collisions at √s = 13TeV for ZZ and at √s = 8TeV forW±Z and W±W± at the LHC at CERN. The cross sections are found to be in agreement with the expectations from the Standard Model within the estimated uncertainties. The production cross section measurements also allow for studies of anomalous triple and quartic gauge couplings for which 95% confidence level limits are set

    Study of TileCal Sampling Fraction for Improvement of Monte-Carlo Data Reconstruction

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    In this work we made a detailed calculation of Tile Calorimeter Sampling Fraction parameter (TSF) using single electron and pion Geant4 Monte-Carlo simulation of ATLAS hadronic calorimeter (TileCal) within ATHENA --- common software framework of ATLAS. Our study was based on MC Truth data provided by special Geant4 MC simulation objects --- Calibration Hits, design which was implemented in TileCal simulation by our group. We used this TSF value for reconstruction of TileCal single pions simulation data. It was done for ATLAS Combined test beam 2004 (CTB2004) configuration setup. Results of the reconstruction were compared with MC Truth and CTB2004 reconstructed experimental data. Good agreement between them shows quite evident improvement in TileCal MC data reconstruction of hadronic shower energy in electromagnetic scale

    The Effect of Tile Light Collection Reduction along Radius on the ATLAS Tile Calorimeter Uniformity

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    We report on the light collection non uniformity of trapezoidal scintillating tiles along radius and its consequence on the miscalibration of the middle and back longitudinal calorimeter samplings. We discuss the need to apply extra corrections to the cells response after equalization and corrections obtained by the cesium calibration system, in order to bring all three longitudinal samplings to the right electromagnetic scale

    Electromagnetic Cell Level Calibration for ATLAS Tile Calorimeter Modules

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    We have determined the electromagnetic calibration constants of 11% TileCal modules exposed to electron beams with incident angles of 20 and 90 degrees. The gain of all the calorimeter cells have been pre-equalized using the radioactive Cs-source that will be also used in situ. The average values for these modules are equal to: for the flat filter method 1.154+/-0.002 pC/GeV and 1.192+/-0.002 pC/GeV for 20 and 90 degrees, for the fit method 1.040+/-0.002 pC/GeV and 1.068+/-0.003 pC/GeV, respectively. These average values for all cells of calibrated modules agree with the weighted average calibration constants for separate modules within the errors. Using the individual calibration constants for every module the RMS spread value of constants will be 1.9+/-0.1 %. In the case of the global constant this value will be 2.6+/-0.1 %. Finally, we present the global constants which should be used for the electromagnetic calibration of the ATLAS Tile hadronic calorimeter data in the ATHENA framework. These constants are equal to 1.15 pC/GeV in the case of the flat filter method and 1.04 pC/GeV for the fit one

    Разработка макета распределенной сенсорной системы экологического мониторинга

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    Introduction. In this article, the basic principles of ecological monitoring were considered, and the possibilities of constructing sensor systems were analysed. It was proposed to use the NB-IoT low-energy telecommunication standard as a basic wireless protocol for ecological system development, which ensures effective communication of network devices. A prototype of the system was constructed, and algorithms for receiving and transmitting signals were simulated.Aim. To construct a prototype of a transceiver based on the NB-IoT standard and perform its simulation. To utilize digital twin in MatLab to create the proposed system.Materials and methods. The prototype was constructed using the Xilinx Zedboard evaluation board and transceiver on AD9361 chip, and the simulation was performed using the MatLab 2010 software package.Results. The results of the simulation in the channel with the additive white Gaussian noise (AWGN) were obtained, and the level of the detected synchronization signals of the NB-IoT standard was determined. The receiver and transmitter of the NB-IoT standard were implemented on the Xilinx Zedboard evaluation board. The timing simulation results show that the designed system can be tested in a real environment. The power consumption and resource utilization of the constructed wireless sensor network prototype unit were determined. Conclusion. The results obtained via the simulation process show that the designed prototype of the communication system works correctly, and the produced signal meets all the requirements of the NB-IoT standard. The results can be used for creating a domestic manufactured, specialized integrated chip for data units of ecological monitoring systems.Введение. Рассмотрены основные принципы осуществления экологического мониторинга; проанализированы возможности построения сенсорных систем для осуществления этой задачи. В качестве протокола беспроводной связи создаваемой системы экомониторинга предложено использование телекоммуникационного стандарта с низким энергопотреблением NB-IoT, обеспечивающего эффективное сетевое взаимодействие устройств сети. Проведено моделирование системы и макетирование алгоритмов приема и передачи сигналов.Цель работы. Построить макет приемопередатчика по стандарту NB-IoT и провести его имитационное моделирование. Использовать маршрут создания системы с формированием ее цифрового двойника в MatLab.Материалы и методы. Прототип построен c использованием отладочной платы Xilinx Zedboard и приемопередатчика на основе микросхемы AD9361, а имитационная модель – при помощи пакета программ MatLab 2010.Результаты. Получены результаты имитационного моделирования в канале с аддитивным белым гауссовским шумом, определена мощность обнаруживаемых сигналов синхронизации стандарта NB-IoT. Приемник и передатчик стандарта NB-IoT реализованы на плате Xilinx Zedboard. Временны́е диаграммы, полученные в ходе тестирования макета, демонстрируют, что разработанная система готова к тестированию в реальной среде. Определены энергетические и ресурсные затраты разработанного макета узла беспроводной сенсорной сети.Заключение. Полученные результаты моделирования показывают, что разработанная модель системы связи функционирует корректно и формируемый сигнал передатчика соответствует требованиям стандарта NB-IoT. Результаты разработки можно использовать для создания отечественной микросхемы узла сбора и передачи данных мониторинга окружающей среды

    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+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \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

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector