10 research outputs found

    NSC KIPT Linux cluster for computing within the CMS physics program

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    The architecture of the NSC KIPT specialized Linux cluster constructed for carrying out work on CMS physics simulations and data processing is described. The configuration of the portable batch system (PBS) on the cluster is outlined. Capabilities of the cluster in its current configuration to perform CMS physics simulations are pointed out

    Investigations of thermal plasma with metal impurities. Part І: The influence of electrodes composition on plasma properties

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    Present paper deals with spectroscopic investigations of electric arc discharge plasma in argon flow between Cu- Mo and Cu-Mo-LaB₆ composite electrodes. Obtained profiles of temperature and electron density were used for calculation of plasma composition and metals’ content in assumption of local thermodynamic equilibrium (LTE). Significant influence of LaB₆ admixture on plasma properties was found.Pабота посвящена спектроскопическим исследованиям плазмы электродугового разряда между Cu-Mo и Cu-Mo-LaB₆ композитными электродами в потоке аргона. Полученные распределения температуры и электронной концентрации использованы для расчета состава плазмы и содержания металлов в предположении состояния локального термодинамического равновесия. Установлено существенное влияние примеси LaB₆ на свойства плазмы.Pобота присвячена спектроскопічним дослідженням плазми електродугового розряду між композитними Cu-Mo та Cu-Mo-LaB₆ композитними електродами в потоці аргону. Отримані розподіли температури та електронної концентрації використано для розрахунку складу плазми та вмісту металів у припущенні стану локальної термодинамічної рівноваги. Встановлено суттєвий вплив домішки LaB₆ на властивості плазми

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

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    On the possibility to observe a heavy Higgs via H⁰ →Z⁰Z⁰ →llνν decays at CMS

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    A possibility to observe with the CMS a heavy (MH 200 GeV/c²) Higgs decaying via H⁰ → Z⁰Z⁰ → llνν is studied. It is suggested that for Higgs masses close to threshold of H⁰ decay to the Z⁰Z⁰ pair. The “irreducible” background due to non-resonance production of weak boson pairs can be eliminated by a proper choice of event selection criteria leading to signature “l⁺ l⁻ + ET miss+ jets”. This observation is illustrated by PYTHIA/CMSJET simulations. For suppression of the Z+jets and tt contributions to the background, two sets of kinematics cuts are considered.Досліджено можливість знаходження важкого бозона Хіггса через розпади H⁰ → Z⁰Z⁰ → llνν. Припускалося, що маса частки Хіггса близька до порогу розпаду на ZZ. Неприводимий фон пов’язаний з нерезонансним народженням векторних бозонів може бути подавлений завдяки вибору критеріїв відбору подій, що ведуть до сигнатури сигналу “l⁺l⁻ + ETmiss+ jets”. Цей результат проілюстровано за допомогою PYTHIA/CMSJET моделювання. Розглянуто два набори критеріїв відбору подій для подавленя tt та Z+jets компонент фону.Изучена возможность обнаружения тяжелого бозона Хиггса посредством H⁰ → Z⁰Z⁰ → llνν распадов. Предполагалось, что масса частицы Хиггса близка к порогу распада на ZZ. Неприводимый фон, связанный с нерезонансным рождением векторных бозонов может быть подавлен путем выбора критериев отбора событий, которые приводят к сигнатуре сигнала “l⁺l⁻ + ETmiss+ jets”. Этот результат был проиллюстрирован с помощью PYTHIA/CMSJET моделирования. Рассмотрено два набора критериев отбора событий для подавления tt и Z+jets составляющих фона

    Synthesis and characterization of fluorinated poly(azomethine ether)s from new core-fluorinated azomethine-containing monomers

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    <div><p></p><p>In this work, we describe the design and synthesis of novel core-fluorinated Schiff base monomers and conjugated polymers based on them. The new fully aromatic highly fluorinated poly(azomethine ether)s (PAMEs) were prepared by polycondensation of core-fluorinated azomethine-containing compounds. The structure of the monomers and polymers were confirmed by FTIR, <sup>1</sup>H, <sup>13</sup>C, and <sup>19</sup>F NMR spectroscopic analysis. The influence of synthesis condition on the properties of PAME compounds was investigated. Application of polarization microscopy with a temperature control thermal stage revealed thermotropic liquid crystalline (LC) behavior in the synthesized materials. Transition temperatures and a range of the existence of the LC phase were studied by a combination of the optical microscopy and DSC analysis. According to the TGA analysis, all the synthesized PAMEs show high thermal stability and thus offer a wide range of thermal processibility (up to 410–477 °C), which makes them prospective materials for many modern applications.</p></div

    A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

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    The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force-the W+, W-, and Z(0) bosons-as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 x 10(6). The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga-electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

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    The article is the pre-print version of the final publishing paper that is available from the link below.Results are presented from searches for the standard model Higgs boson in proton–proton collisions At √s = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 fb−1 at 7TeV and 5.3 fb−1 at 8 TeV. The search is performed in five decay modes: γγ, ZZ, W+W−, τ+τ−, and bb. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, γγ and ZZ; a fit to these signals gives a mass of 125.3±0.4(stat.)±0.5(syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one

    CMS physics technical design report: Addendum on high density QCD with heavy ions

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    This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies ,will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction - Quantum Chromodynamics (QCD) - in extreme conditions of temperature, density and parton momentum fraction (low-x). This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield "tomographic" information of the hottest and densest phases of the reaction.0info:eu-repo/semantics/publishe
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