9 research outputs found

    Does illegal immigration empower rightist parties?

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    The main goal of this paper is to analyze the political outcome in countries where the relevant issue in elections is the control of immigration. In particular we explore the consequences on the political outcome of the fact that parties are either ideological or opportunistic with respect to this issue. In order to do that we use a simple two-party political competition model in which the issues over which parties take positions are the level of border enforcement and the way it has to be financed. We show that an ideological rather than a pure opportunistic behavior gives parties an advantage to win the election. In particular, in most of the cases we consider we find that rightist parties have an advantage to win in countries where the relevant issue in election is illegal immigration. This result may help us to understand the recent success of anti-immigrant and rightist parties in several countries.illegal immigration, skilled, unskilled, ideology

    Combined measurements of Higgs boson couplings in proton- proton collisions at v s=13TeV

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    Combined measurements of the production and decay rates of the Higgs boson, as well as its couplings to vector bosons and fermions, are presented. The analysis uses the LHC proton-proton collision data set recorded with the CMS detector in 2016 at fb-1. The combination is based on analyses targeting the five main Higgs boson production mechanisms (gluon fusion, vector boson fusion, and associated production with a W or Z boson, or a top quark-antiquark pair) and the following decay modes: H, ZZ, WW, , bb, and . Searches for invisible Higgs boson decays are also considered. The best-fit ratio of the signal yield to the standard model expectation is measured to be =1.17 +/- 0.10, assuming a Higgs boson mass of 125.09. Additional results are given for various assumptions on the scaling behavior of the production and decay modes, including generic parametrizations based on ratios of cross sections and branching fractions or couplings. The results are compatible with the standard model predictions in all parametrizations considered. In addition, constraints are placed on various two Higgs doublet models.Peer reviewe

    Measurement of prompt D-0 and D-0 meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at root S-NN=5.02 TeV

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    Measurement of charged particle spectra in minimum-bias events from proton-proton collisions at root s =13 TeV

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    Pseudorapidity, transverse momentum, and multiplicity distributions are measured in the pseudorapidity range vertical bar eta vertical bar 0.5 GeV in proton-proton collisions at a center-of-mass energy of root s = 13 TeV. Measurements are presented in three different event categories. The most inclusive of the categories corresponds to an inelastic pp data set, while the other two categories are exclusive subsets of the inelastic sample that are either enhanced or depleted in single diffractive dissociation events. The measurements are compared to predictions from Monte Carlo event generators used to describe high-energy hadronic interactions in collider and cosmic-ray physics.Peer reviewe

    Measurement of the CP-violating phase phi_s in the Bs0^0_\mathrm{s}\to J/ψϕ/\psi\, \phi(1020) μ+μ\to \mu^+\mu^-K+^+K^- channel in proton-proton collisions at s=\sqrt{s} = 13 TeV

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    The CP-violating weak phase ?s and the decay width difference ??s between the light and heavy B0s mass eigenstates are measured with the CMS detector at the LHC in a sample of 48 500 reconstructed B0s? J/I) d (1020) ?11+11? K+K? events. The measurement is based on a data sample corresponding to an integrated luminosity of 96.4 fb?1, collected in proton-proton collisions at ?s = 13 TeV in 2017?2018. To extract the values of ?s and ??s, a time-dependent and flavor-tagged angular analysis of the 11+11?K+K? final state is performed. The analysis employs a dedicated tagging trigger and a novel opposite-side muon flavor tagger based on machine learning techniques. The measurement yields ?s = ?11 ?50 (stat) ? 10 (syst) mrad and ??s = 0.114 ? 0.014 (stat)? 0.007 (syst) ps?1, in agreement with the standard model predictions. When combined with the previous CMS measurement at ?s = 8 TeV, the following values are obtained: ?s = ?21 ? 44 (stat) ? 10 (syst) mrad, ??s = 0.1032 ? 0.0095 (stat) ? 0.0048 (syst) ps?1, a significant improvement over the 8 TeV result. ? 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY licens

    Observation of B<inf>s</inf><sup>0</sup> mesons and measurement of the B<inf>s</inf><sup>0</sup>/B<sup>+</sup> yield ratio in PbPb collisions at [Formula presented] TeV

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    The Bs0 and B+ production yields are measured in PbPb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data sample, collected with the CMS detector at the LHC, corresponds to an integrated luminosity of 1.7 nb−1. The mesons are reconstructed in the exclusive decay channels B→s0J/ψ(μ+μ−)ϕ(K+K−) and B→+J/ψ(μ+μ−)K+, in the transverse momentum range 7–50 GeV/c and absolute rapidity 0–2.4. The Bs0 meson is observed with a statistical significance in excess of five standard deviations for the first time in nucleus-nucleus collisions. The measurements are performed as functions of the transverse momentum of the B mesons and of the PbPb collision centrality. The ratio of production yields of Bs0 and B+ is measured and compared to theoretical models that include quark recombination effects

    Measurement of the C P-violating phase φs in the B0 s → J/ψφ(1020) → μ+μ− K+K− channel in proton-proton collisions at √s = 13 TeV

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    The C P-violating weak phase φs and the decay width difference s between the light and heavy B0 s mass eigenstates are measured with the CMS detector at the LHC in a sample of 48 500 reconstructed B0 s → J/ψ φ(1020) → μ+μ− K+K− events. The measurement is based on a data sample corresponding to an integrated luminosity of 96.4 fb−1, collected in proton-proton collisions at √s = 13 TeV in 2017–2018. To extract the values of φs and s, a time-dependent and flavor-tagged angular analysis of the μ+μ−K+K− final state is performed. The analysis employs a dedicated tagging trigger and a novel opposite-side muon flavor tagger based on machine learning techniques. The measurement yields φs = −11±50 (stat)±10 (syst) mrad and s = 0.114±0.014 (stat)±0.007 (syst) ps−1, in agreement with the standard model predictions. When combined with the previous CMS measurement at √s = 8 TeV, the following values are obtained: φs = −21 ± 44 (stat) ± 10 (syst) mrad, s = 0.1032 ± 0.0095 (stat) ± 0.0048 (syst) ps−1, a significant improvement over the 8 TeV result

    Fragmentation of jets containing a prompt J/psi meson in PbPb and pp collisions at root s(NN)=5.02 TeV

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    Jets containing a prompt J/ψ meson are studied in lead-lead collisions at a nucleon-nucleon center-ofmass energy of 5.02 TeV, using the CMS detector at the LHC. Jets are selected to be in the transverse momentum range of 30 < pT < 40 GeV. The J/ψ yield in these jets is evaluated as a function of the jet fragmentation variable z, the ratio of the J/ψ pT to the jet pT. The nuclear modification factor, RAA, is then derived by comparing the yield in lead-lead collisions to the corresponding expectation based on proton-proton data, at the same nucleon-nucleon center-of-mass energy. The suppression of the J/ψ yield shows a dependence on z, indicating that the interaction of the J/ψ with the quark-gluon plasma formed in heavy ion collisions depends on the fragmentation that gives rise to the J/ψ meson

    Observation of B-s(0) mesons and measurement of the B-s(0)/B+ yield ratio in PbPb collisions at root S-NN=5.02 TeV

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    The B0 s and B+ production yields are measured in PbPb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data sample, collected with the CMS detector at the LHC, corresponds to an integrated luminosity of 1.7 nb−1. The mesons are reconstructed in the exclusive decay channels B0 s → J/ψ(μ+μ−)φ(K+K−) and B+ → J/ψ(μ+μ−)K+, in the transverse momentum range 7–50 GeV/c and absolute rapidity 0–2.4. The B0 s meson is observed with a statistical significance in excess of five standard deviations for the first time in nucleus-nucleus collisions. The measurements are performed as functions of the transverse momentum of the B mesons and of the PbPb collision centrality. The ratio of production yields of B0 s and B+ is measured and compared to theoretical models that include quark recombination effects
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