512 research outputs found

    Métodos de separación de los elementos metálicos

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    1 archivo PDF (119 páginas)En general, todos los materiales de manejo cotidiano como el cemento, ladrillo, rocas, aceros, aguas residuales contienen en su composición a la mayoría de los elementos químicos, pero sólo a unos cuantos o a uno de ellos en mayor proporción y los demás en cantidades minúsculas

    Métodos de separación de los elementos metálicos 

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    En general, todos los materiales de manejo cotidiano como el cemento, ladrillo, rocas, aceros, aguas residuales contienen en su composición a la mayoría de los elementos químicos, pero sólo a unos cuantos o a uno de ellos ..

    Measurement and QCD analysis of double-differential inclusive jet cross sections in proton-proton collisions at s \sqrt{s} = 13 TeV

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    International audienceA measurement of the inclusive jet production in proton-proton collisions at the LHC at s \sqrt{s} = 13 TeV is presented. The double-differential cross sections are measured as a function of the jet transverse momentum pT_{T} and the absolute jet rapidity |y|. The anti-kT_{T} clustering algorithm is used with distance parameter of 0.4 (0.7) in a phase space region with jet pT_{T} from 97 GeV up to 3.1 TeV and |y| < 2.0. Data collected with the CMS detector are used, corresponding to an integrated luminosity of 36.3 fb1^{−1} (33.5 fb1^{−1}). The measurement is used in a comprehensive QCD analysis at next-to-next-to-leading order, which results in significant improvement in the accuracy of the parton distributions in the proton. Simultaneously, the value of the strong coupling constant at the Z boson mass is extracted as αS_{S}(mZ_{Z}) = 0.1170±0.0019. For the first time, these data are used in a standard model effective field theory analysis at next-to-leading order, where parton distributions and the QCD parameters are extracted simultaneously with imposed constraints on the Wilson coefficient c1_{1} of 4-quark contact interactions.[graphic not available: see fulltext

    Development of the CMS detector for the CERN LHC Run 3

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    International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

    Search for narrow resonances in the <math display="inline"><mi>b</mi></math>-tagged dijet mass spectrum in proton-proton collisions at <math display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>

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    International audienceA search is performed for narrow resonances decaying to final states of two jets, with at least one jet originating from a b quark, in proton-proton collisions at s=13  TeV. The data set corresponds to an integrated luminosity of 138  fb-1 collected with the CMS detector at the LHC. Jets originating from energetic b hadrons are identified through a b-tagging algorithm that utilizes a deep neural network or the presence of a muon inside a jet. The invariant mass spectrum of jet pairs is well described by a smooth parametrization and no evidence for the production of new particles is observed. Upper limits on the production cross section are set for excited b quarks and other resonances decaying to dijet final states containing b quarks. These limits exclude at 95% confidence level models of Z′ bosons with masses from 1.8 TeV to 2.4 TeV and of excited b quarks with masses from 1.8 TeV to 4.0 TeV. This is the most stringent exclusion of excited b quarks to date

    Development of the CMS detector for the CERN LHC Run 3

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    International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

    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

    Development of the CMS detector for the CERN LHC Run 3

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    International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

    Observation of the Bc+_\mathrm{c}^+ meson in PbPb and pp collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    The Bc+_\mathrm{c}^+ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to measure the production of the Bc+_\mathrm{c}^+ meson in lead-lead (PbPb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV, via the Bc+_\mathrm{c}^+\to (J/ψ\psi\toμ+μ\mu^+\mu^-)μ+νμ\mu^+\nu_\mu decay. The Bc+_\mathrm{c}^+ nuclear modification factor, derived from the PbPb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the PbPb collision centrality. The Bc+_\mathrm{c}^+ meson is shown to be less suppressed than other quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This first observation of the Bc+_\mathrm{c}^+ meson in heavy ion collisions sets forth a new promising probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma

    Search for heavy resonances and quantum black holes in eμ\mu, eτ\tau, and μτ\mu\tau final states in proton-proton collisions at s\sqrt{s} = 13 TeV

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    A search is reported for heavy resonances and quantum black holes decaying into eμ\mu, eτ\tau, and μτ\mu\tau final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016-2018 at s=\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The eμ\mu, eτ\tau, and μτ\mu\tau 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 τ\tau sneutrino production in RR parity violating supersymmetric models, heavy Z' gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant τ\tau sneutrinos are excluded for masses up to 4.2 TeV in the eμ\mu channel, 3.7 TeV in the eτ\tau channel, and 3.6 TeV in the μτ\mu\tau channel. A Z' boson with lepton flavor violating couplings is excluded up to a mass of 5.0 TeV in the eμ\mu channel, up to 4.3 TeV in the eτ\tau channel, and up to 4.1 TeV in the μτ\mu\tau channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6 TeV in the eμ\mu channel, 5.2 TeV in the eτ\tau channel, and 5.0 TeV in the μτ\mu\tau 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.A search is reported for heavy resonances and quantum black holes decaying into eμ, eτ, and μτ final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016–2018 at s \sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{−1}. The eμ, eτ, and μτ 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 τ sneutrino production in R parity violating supersymmetric models, heavy Z′ gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant τ sneutrinos are excluded for masses up to 4.2TeV in the eμ channel, 3.7TeV in the eτ channel, and 3.6TeV in the μτ channel. A Z′ boson with lepton flavor violating couplings is excluded up to a mass of 5.0TeV in the eμ channel, up to 4.3Te V in the eτ channel, and up to 4.1TeV in the μτ channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6TeV in the eμ channel, 5.2TeV in the eτ channel, and 5.0TeV in the μτ 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.[graphic not available: see fulltext]A search is reported for heavy resonances and quantum black holes decaying into eμ\mu, eτ\tau, and μτ\mu\tau final states in proton-proton collision data recorded by the CMS experiment at the CERN LHC during 2016-2018 at s\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The eμ\mu, eτ\tau, and μτ\mu\tau 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 τ\tau sneutrino production in RR parity violating supersymmetric models, heavy Z' gauge bosons with lepton flavor violating decays, and nonresonant quantum black hole production in models with extra spatial dimensions. Resonant τ\tau sneutrinos are excluded for masses up to 4.2 TeV in the eμ\mu channel, 3.7 TeV in the eτ\tau channel, and 3.6 TeV in the μτ\mu\tau channel. A Z' boson with lepton flavor violating couplings is excluded up to a mass of 5.0 TeV in the eμ\mu channel, up to 4.3 TeV in the eτ\tau channel, and up to 4.1 TeV in the μτ\mu\tau channel. Quantum black holes in the benchmark model are excluded up to the threshold mass of 5.6 TeV in the eμ\mu channel, 5.2 TeV in the eτ\tau channel, and 5.0 TeV in the μτ\mu\tau 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
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