8,552 research outputs found

    Linkages between the MDGs and PRSPs in Transitional Countries of Eurasia

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    The paper looks at linkages between MDGs and PRSPs in six transition countries: Armenia, Azerbaijan, Georgia, Kyrgyz Republic, Mongolia, and Tajikistan. Progress towards MDG attainment in all these countries is considered. Key features of PRSPs in the countries of the sub-region are analyzed. Against this background, the linkages and consistency between MDGs and PRSPs are discussed in the paper.MDG, PRSP, transition countries

    First Search for Exclusive Diphoton Production at High Mass with Tagged Protons in Proton-Proton Collisions at āˆšs =13 TeV

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    A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp ā†’ pĪ³Ī³p with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fbāˆ’1 collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeVat the LHC. Events are selected with a diphoton invariant mass above 350 GeVand with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% confidence level are |Ī¶1| \u3c 2.9 Ɨ 10āˆ’13 GeVāˆ’4 and |Ī¶2| \u3c 6.0 Ɨ 10āˆ’13 GeVāˆ’4

    Measurements of jet multiplicity and jet transverse momentum in multijet events in protonā€“proton collisions at āˆšs = 13TeV

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    Multijet events at large transverse momentum (pT) are measured at āˆš s = 13 TeV using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 36.3 fbāˆ’1. The multiplicity of jets with pT \u3e 50 GeV that are produced in association with a high-pT dijet system is measured in various ranges of the pT of the jet with the highest transverse momentum and as a function of the azimuthal angle difference Ī”Ļ†1,2 between the two highest pT jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest pT jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower

    Search for Flavor-Changing Neutral Current Interactions of the Top Quark and Higgs Boson in Final States with Two Photons in Proton-Proton Collisions at āˆšs =13 TeV

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    Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fbāˆ’1. No significant excess above the background prediction is observed. Upper limits on the branching fractions (ʁ) of the top quark decaying to a Higgs boson and an up (u) or charm (c) quark are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019% (0.031%) for ʁ(t ā†’ Hu) and 0.073% (0.051%) for ʁ(t ā†’ Hc). These are the strictest upper limits yet determined

    Search for higgsinos decaying to two Higgs bosons and missing transverse momentum in proton-proton collisions at āˆšs = 13 TeV

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    Results are presented from a search for physics beyond the standard model in proton-proton collisions at āˆšs = 13TeV in channels with two Higgs bosons, each decaying via the process H āŸ¶ b[], and large missing transverse momentum. The search uses a data sample corresponding to an integrated luminosity of 137 fbāˆ’1 collected by the CMS experiment at the CERN LHC. The search is motivated by models of supersymmetry that predict the production of neutralinos, the neutral partners of the electroweak gauge and Higgs bosons. The observed event yields in the signal regions are found to be consistent with the standard model background expectations. The results are interpreted using simplified models of supersymmetry. For the electroweak production of nearly mass-degenerate higgsinos, each of whose decay chains yields a neutralino ([]01 ) that in turn decays to a massless goldstino and a Higgs boson, []01 masses in the range 175 to 1025 GeV are excluded at 95% confidence level. For the strong production of gluino pairs decaying via a slightly lighter []02 to H and a light []01, gluino masses below 2330 GeV are excluded

    Search for heavy resonances and quantum black holes in eĪ¼, eĻ„, and Ī¼Ļ„ final states in proton-proton collisions at āˆšs = 13 TeV

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    A search is reported for heavy resonances and quantum black holes decaying into eĪ¼, eĻ„, and Ī¼Ļ„ final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016ā€“2018 at āˆšs = 13TeV, corresponding to an integrated luminosity of 138 fbāˆ’1. The eĪ¼, eĻ„, and Ī¼Ļ„ invariant mass spectra are reconstructed, and no evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on the product of the cross section and branching fraction for lepton flavor violating signals. Three benchmark signals are studied: resonant Ļ„ sneutrino production in R parity violating supersymmetric models, heavy Z\u27 gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant Ļ„ sneutrinos are excluded for masses up to 4.2TeV in the eĪ¼ channel, 3.7TeV in the eĻ„ channel, and 3.6TeV in the Ī¼Ļ„ channel. A Z\u27 boson with lepton flavor violating couplings is excluded up to a mass of 5.0TeV in the eĪ¼ channel, up to 4.3Te V in the eĻ„ channel, and up to 4.1TeV in the Ī¼Ļ„ channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6TeV in the eĪ¼ channel, 5.2Te V in the eĻ„ channel, and 5.0TeV in the Ī¼Ļ„ channel. In addition, model-independent limits are extracted to allow comparisons with other models for the same final states and similar event selection requirements. The results of these searches provide the most stringent limits available from collider experiments for heavy particles that undergo lepton flavor violating decays

    Two-particle azimuthal correlations in Ī³p interactions using pPb collisions at āˆšs\u3csub\u3eNN\u3c/sub\u3e=8.16TeV

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    The first measurements of the Fourier coefficients (VnĪ”) of the azimuthal distributions of charged hadrons emitted from photon-proton (Ī³p) interactions are presented. The data are extracted from 68.8nbāˆ’1of ultra-peripheral proton-lead (pPb) collisions at āˆšsNN=8.16 TeVusing the CMS detector. The high energy lead ions produce a flux of photons that can interact with the oncoming proton. This Ī³p system provides a set of unique initial conditions with multiplicity lower than in photon-lead collisions but comparable to recent electron-positron and electron-proton data. The VnĪ” coefficients are presented in ranges of event multiplicity and transverse momentum (pT) and are compared to corresponding hadronic minimum bias pPb results. For a given multiplicity range, the mean pT of charged particles is smaller in Ī³p than in pPb collisions. For both the Ī³p and pPb samples, V1Ī” is negative, V2Ī” is positive, and V3Ī” consistent with 0. For each multiplicity and pT range, V2Ī” is larger for Ī³p events. The Ī³p data are consistent with model predictions that have no collective effects

    Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions

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    The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at āˆšsNN = 5.02 TeV, corresponding to an integrated luminosity of 0.38 nbāˆ’1, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. Awell-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects

    Erratum: Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV

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    In Fig. 3, the y axis titles were mistakenly written showing a single-differential cross section in either dimuon pT or rapidity, when in fact the cross section is normalized by both the pT and rapidity ranges used for a given measurement point. The corrected version is shown in the new Fig. 3 provided below
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