439 research outputs found

    Current issues of security management during martial law

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    The authors of the book have come to the conclusion that toensuring the country’s security in the conditions of military aggression, it is necessary to use the mechanisms of protection of territories and population, support of economic entities, international legal levers of influence on the aggressor country. Basic research focuses on assessment the resource potential of enterprises during martial law, the analysis of migration flows in the middle of the country and abroad, the volume of food exports, marketing and logistics system. The research results have been implemented in the different decision-making models during martial law, information and economic security management, formation of personnel potential and assets of enterprises, food, energy and environmental security management, use of budgetary levers and financial instruments. The results of the study can be used in the developing of directions, programs and strategies for the post-war recovery of Ukraine’s economy and the attraction of foreign investments in the regions, decision-making at the level of ministries and agencies that regulate security management processes. The results can also be used by students and young scientists in the educational process and conducting scientific research on the problems of ensuring the country’s security

    Measurement of the double-differential inclusive jet cross section in proton-proton collisions at s\sqrt{s} = 5.02 TeV

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    International audienceThe inclusive jet cross section is measured as a function of jet transverse momentum pTp_\mathrm{T} and rapidity yy. The measurement is performed using proton-proton collision data at s\sqrt{s} = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb1^{-1}. The jets are reconstructed with the anti-kTk_\mathrm{T} algorithm using a distance parameter of RR = 0.4, within the rapidity interval y\lvert y\rvert<\lt 2, and across the kinematic range 0.06 <\ltpTp_\mathrm{T}<\lt 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling αS\alpha_\mathrm{S}

    Inclusive nonresonant multilepton probes of new phenomena at s\sqrt{s} = 13 TeV

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    An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying τ\tau leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb1^{-1} of proton-proton collisions at s\sqrt{s} = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vector-like τ\tau lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vector-like doublet model, these constraints are the most stringent to date. For the vector-like singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations

    Two-particle Bose-Einstein correlations and their Lévy parameters in PbPb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV

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    International audienceTwo-particle Bose-Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV. The data sample, containing 4.27×109\times10^{9} minimum bias events corresponding to an integrated luminosity of 0.607 nb1^{-1}, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter (α\alpha), the Lévy scale parameter (RR), and the correlation strength parameter (λ\lambda). The source shape, characterized by α\alpha, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a hydrodynamical scaling is observed for the Lévy RR parameter. The λ\lambda parameter is studied in terms of the core-halo model

    Measurement of the production cross section for Z+b jets in proton-proton collisions at s\sqrt s = 13 TeV

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    The measurement of the cross section for the production of a Z boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet are performed with proton-proton collision data at s\sqrt{s} = 13 TeV. The data sample corresponds to an integrated luminosity of 137 fb1^{-1}, collected by the CMS experiment at the LHC during 2016-2018. The integrated cross sections for Z + \ge1 b jet and Z + \ge2 b jets are reported for the electron, muon, and combined channels. The fiducial cross sections in the combined channel are 6.52 ±\pm 0.04 (stat) ±\pm 0.40 (syst) ±\pm 0.14 (theo) pb for Z + \ge1 b jet and 0.65 ±\pm 0.03 (stat) ±\pm 0.07 (syst) ±\pm 0.02 (theo) pb for Z + \ge2 b jets. The differential cross section distributions are measured as functions of various kinematic observables that are useful for precision tests of perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections for Z + \ge2 b jets and Z + \ge1 b jet processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 ±\pm 0.005 (stat) ±\pm 0.007 (syst) ±\pm 0.003 (theo). All measurements are compared with predictions from various event generators

    Search for resonances decaying to three W bosons in the hadronic final state in proton-proton collisions at s\sqrt{s} = 13 TeV

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    A search for Kaluza-Klein excited vector boson resonances, WKK_\mathrm{KK}, decaying in cascade to three W bosons via a scalar radion R, WKK_\mathrm{KK}\to WR \to WWW, with two or three massive jets is presented. The search is performed with proton-proton collision data recorded at s\sqrt{s} = 13 TeV, collected by the CMS experiment at the CERN LHC, during 2016-2018, corresponding to an integrated luminosity of 138 fb1^{-1}. Two final states are simultaneously probed, one where the two W bosons produced by the R decay are reconstructed as separate, large-radius, massive jets, and one where they are merged in a single large-radius jet. The data observed are in agreement with the standard model expectations. Limits are set on the product of the WKK_\mathrm{KK} resonance cross section and branching fraction to three W bosons in an extended warped extra-dimensional model and are the first of their kind at the LHC

    Search for Higgs boson decays to a Z boson and a photon in proton-proton collisions at s \sqrt{s} = 13 TeV

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    International audienceResults are presented from a search for the Higgs boson decay H → Zγ, where Z → ℓ+^{+}^{−} with ℓ = e or μ. The search is performed using a sample of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb1^{−1}. Events are assigned to mutually exclusive categories, which exploit differences in both event topology and kinematics of distinct Higgs production mechanisms to enhance signal sensitivity. The signal strength μ, defined as the product of the cross section and the branching fraction \left[\sigma \left(\textrm{pp}\to \textrm{H}\right)\mathcal{B}\left(\textrm{H}\to \textrm{Z}\upgamma \right)\right] relative to the standard model prediction, is extracted from a simultaneous fit to the ℓ+^{+}^{−}γ invariant mass distributions in all categories and is measured to be μ = 2.4 ± 0.9 for a Higgs boson mass of 125.38 GeV. The statistical significance of the observed excess of events is 2.7 standard deviations. This measurement corresponds to \left[\sigma \left(\textrm{pp}\to \textrm{H}\right)\mathcal{B}\left(\textrm{H}\to \textrm{Z}\upgamma \right)\right]=0.21\pm 0.08 pb. The observed (expected) upper limit at 95% confidence level on μ is 4.1 (1.8), where the expected limit is calculated under the background-only hypothesis. The ratio of branching fractions \mathcal{B}\left(\textrm{H}\to \textrm{Z}\upgamma \right)/\mathcal{B}\left(\textrm{H}\to \upgamma \upgamma \right) is measured to be 1.50.6+0.7 {1.5}_{-0.6}^{+0.7} , which agrees with the standard model prediction of 0.69 ± 0.04 at the 1.5 standard deviation level.[graphic not available: see fulltext

    Measurement of the production cross section for a W boson in association with a charm quark in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceThe strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis uses a data sample corresponding to a total integrated luminosity of 138 fb1^{-1} collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The W+c production cross section and the cross section ratio Rc±R^\pm_\text{c} = σ\sigma(W+^++cˉ\bar{\text{c}})/σ\sigma(W^-+c\text{c}) are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in Rc±R^\pm_\text{c}. The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics

    Two-particle Bose-Einstein correlations and their Lévy parameters in PbPb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV

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    International audienceTwo-particle Bose-Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV. The data sample, containing 4.27×109\times10^{9} minimum bias events corresponding to an integrated luminosity of 0.607 nb1^{-1}, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter (α\alpha), the Lévy scale parameter (RR), and the correlation strength parameter (λ\lambda). The source shape, characterized by α\alpha, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a hydrodynamical scaling is observed for the Lévy RR parameter. The λ\lambda parameter is studied in terms of the core-halo model

    Search for CP violation using tt \textrm{t}\overline{\textrm{t}} events in the lepton+jets channel in pp collisions at s \sqrt{s} = 13 TeV

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    Results are presented on a search for CP violation in the production and decay of top quark-antiquark pairs in the lepton+jets channel. The search is based on data from proton-proton collisions at s \sqrt{s} = 13 TeV, collected with the CMS detector, corresponding to an integrated luminosity of 138 fb1^{−1}. Possible CP violation effects are evaluated by measuring asymmetries in observables constructed from linearly independent four-momentum vectors of the final-state particles. The dimensionless chromoelectric dipole moment of the top quark obtained from the observed asymmetries is measured to be 0.04 ± 0.10 (stat) ± 0.07(syst), and the asymmetries exhibit no evidence for CP-violating effects, consistent with expectations from the standard model.[graphic not available: see fulltext
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