25 research outputs found

    Search for heavy neutral leptons in final states with electrons, muons, and hadronically decaying tau leptons in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search for heavy neutral leptons (HNLs) of Majorana or Dirac type using proton-proton collision data at = 13 TeV is presented. The data were collected by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 138 fb−1. Events with three charged leptons (electrons, muons, and hadronically decaying tau leptons) are selected, corresponding to HNL production in association with a charged lepton and decay of the HNL to two charged leptons and a standard model (SM) neutrino. The search is performed for HNL masses between 10 GeV and 1.5 TeV. No evidence for an HNL signal is observed in data. Upper limits at 95% confidence level are found for the squared coupling strength of the HNL to SM neutrinos, considering exclusive coupling of the HNL to a single SM neutrino generation, for both Majorana and Dirac HNLs. The limits exceed previously achieved experimental constraints for a wide range of HNL masses, and the limits on tau neutrino coupling scenarios with HNL masses above the W boson mass are presented for the first time

    Measurement of the polarizations of prompt and non-prompt J/ψ and ψ (2S) mesons produced in pp collisions at s\sqrt{s} = 13 TeV

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    The polarizations of prompt and non-prompt J∕ψ and ψ(2S) mesons are measured in proton-proton collisions at √ = 13 TeV, using data samples collected by the CMS experiment in 2017 and 2018, corresponding to a total integrated luminosity of 103.3 fb1^{−1}. Based on the analysis of the dimuon decay angular distributions in the helicity frame, the polar anisotropy, , is measured as a function of the transverse momentum, T_T, of the charmonium states, in the 25–120 and 20–100 GeV ranges for the J∕ψ and ψ(2S), respectively. The non-prompt polarizations agree with predictions based on the hypothesis that, for T ≳ 25 GeV, the non-prompt J∕ψ and ψ(2S) are predominantly produced in two-body B meson decays. The prompt results clearly exclude strong transverse polarizations, even for T_T exceeding 30 times the J∕ψ mass, where tends to an asymptotic value around 0.3. Taken together with previous measurements, by CMS and LHCb at √ = 7 TeV, the prompt polarizations show a significant variation with T_T, at low T_T

    Observation of the J / ψ → μ⁺ μ⁻ μ⁺ μ⁻ decay in proton-proton collisions at √s = 13 TeV

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    Search for new physics in high-mass diphoton events from proton-proton collisions at √s = 13 TeV

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    Results are presented from a search for new physics in high-mass diphoton events from proton-proton collisions at sqrt(s) = 13 TeV. The data set was collected in 2016–2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb−1 . Events with a diphoton invariant mass greater than 500 GeV are considered. Two diferent techniques are used to predict the standard model backgrounds: parametric fts to the smoothly-falling background and a frst-principles calculation of the standard model diphoton spectrum at next-to-next-to-leading order in perturbative quantum chromodynamics calculations. The frst technique is sensitive to resonant excesses while the second technique can identify broad diferences in the invariant mass shape. The data are used to constrain the production of heavy Higgs bosons, Randall-Sundrum gravitons, the large extra dimensions model of Arkani-Hamed, Dimopoulos, and Dvali (ADD), and the continuum clockwork mechanism. No statistically signifcant excess is observed. The present results are the strongest limits to date on ADD extra dimensions and RS gravitons with a coupling parameter greater than 0.1

    Synthesis and Structural Characterization of New Cu(I) Complexes with the Antithyroid Drug 6‑<i>n</i>‑Propyl-thiouracil. Study of the Cu(I)-Catalyzed Intermolecular Cycloaddition of Iodonium Ylides toward Benzo[<i>b</i>]furans with Pharmaceutical Implementations

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    The reaction of copper­(I) iodide with 6-<i>n</i>-propylthiouracil (ptu) in the presence or absence of the triphenylphosphine (tpp) or tri­(<i>p</i>-tolyl)­phosphine (tptp) in a 1:1:2 molar ratio forms the mixed ligand Cu­(I) complex with formula [CuI­(ptu)<sub>2</sub>]­(toluene) (<b>1</b>), [CuI­(tpp)<sub>2</sub>(ptu)] (<b>2</b>), and [CuI­(tptp)<sub>2</sub>(ptu)] (<b>3</b>). The complexes have been characterized by FT-IR, <sup>1</sup>H NMR, UV–vis, spectroscopic techniques, and single crystal X-ray crystallography. Two sulfur atoms from two ptu ligands and one iodide form a trigonal geometry around the metal center in <b>1</b>. Intramolecular interactions through hydrogen bonds lead to a bend ribbon polymeric supramolecular architecture with zigzag conformation. Two phosphorus atoms from two arylphosphines, one sulfur atom, and one iodide anion form a tetrahedron around the copper ion in case of <b>2</b> and <b>3</b>. Intramolecular hydrogen bonding interactions lead to dimerization. Complexes <b>1</b>–<b>3</b> and the already known ones with formulas, [(tpSb)<sub>2</sub>Cu­(μ<sub>2</sub>-I)<sub>2</sub>Cu­(tpSb)<sub>2</sub>] (<b>4</b>) (tbSb = triphenylstibine), [(tpp)­Cu­(μ<sub>2</sub>-I)<sub>2</sub>Cu­(tpp)<sub>2</sub>] (<b>5</b>), [(tpp)­Cu­(μ<sub>2</sub>-Cl)<sub>2</sub>Cu­(tpp)<sub>2</sub>] (<b>6</b>), [CuCl­(tpp)<sub>3</sub>·(CH<sub>3</sub>CN)] (<b>7</b>), and [AuCl­(tpp)] (<b>8</b>), were used to study their catalytic activity on the intermolecular cycloaddition of iodonium ylides toward benzo­[<i>b</i>]­furans formation. The results show that both the metal and the ligand type affect the catalytic affinity of the complexes. The highest yield of benzo­[<i>b</i>]­furan was derived when complexes <b>2</b>,<b> 3</b>, and <b>4</b> were used as catalysts. The mechanism of the Cu­(I)-catalyzed and uncatalyzed intramolecular cycloaddition of iodonium ylide has been also thoroughly explored by means of ab initio electronic structure calculation methods, and the results are compared with the experimental ones

    Synthesis and Structural Characterization of New Cu(I) Complexes with the Antithyroid Drug 6‑<i>n</i>‑Propyl-thiouracil. Study of the Cu(I)-Catalyzed Intermolecular Cycloaddition of Iodonium Ylides toward Benzo[<i>b</i>]furans with Pharmaceutical Implementations

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    The reaction of copper­(I) iodide with 6-<i>n</i>-propylthiouracil (ptu) in the presence or absence of the triphenylphosphine (tpp) or tri­(<i>p</i>-tolyl)­phosphine (tptp) in a 1:1:2 molar ratio forms the mixed ligand Cu­(I) complex with formula [CuI­(ptu)<sub>2</sub>]­(toluene) (<b>1</b>), [CuI­(tpp)<sub>2</sub>(ptu)] (<b>2</b>), and [CuI­(tptp)<sub>2</sub>(ptu)] (<b>3</b>). The complexes have been characterized by FT-IR, <sup>1</sup>H NMR, UV–vis, spectroscopic techniques, and single crystal X-ray crystallography. Two sulfur atoms from two ptu ligands and one iodide form a trigonal geometry around the metal center in <b>1</b>. Intramolecular interactions through hydrogen bonds lead to a bend ribbon polymeric supramolecular architecture with zigzag conformation. Two phosphorus atoms from two arylphosphines, one sulfur atom, and one iodide anion form a tetrahedron around the copper ion in case of <b>2</b> and <b>3</b>. Intramolecular hydrogen bonding interactions lead to dimerization. Complexes <b>1</b>–<b>3</b> and the already known ones with formulas, [(tpSb)<sub>2</sub>Cu­(μ<sub>2</sub>-I)<sub>2</sub>Cu­(tpSb)<sub>2</sub>] (<b>4</b>) (tbSb = triphenylstibine), [(tpp)­Cu­(μ<sub>2</sub>-I)<sub>2</sub>Cu­(tpp)<sub>2</sub>] (<b>5</b>), [(tpp)­Cu­(μ<sub>2</sub>-Cl)<sub>2</sub>Cu­(tpp)<sub>2</sub>] (<b>6</b>), [CuCl­(tpp)<sub>3</sub>·(CH<sub>3</sub>CN)] (<b>7</b>), and [AuCl­(tpp)] (<b>8</b>), were used to study their catalytic activity on the intermolecular cycloaddition of iodonium ylides toward benzo­[<i>b</i>]­furans formation. The results show that both the metal and the ligand type affect the catalytic affinity of the complexes. The highest yield of benzo­[<i>b</i>]­furan was derived when complexes <b>2</b>,<b> 3</b>, and <b>4</b> were used as catalysts. The mechanism of the Cu­(I)-catalyzed and uncatalyzed intramolecular cycloaddition of iodonium ylide has been also thoroughly explored by means of ab initio electronic structure calculation methods, and the results are compared with the experimental ones

    Search for dark QCD with emerging jets in proton-proton collisions at sqrt{s} = 13 TeV

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    A search for ``emerging jets'' produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed using data collected by the CMS experiment corresponding to an integrated luminosity of 138 fb−1. This search examines a hypothetical dark quantum chromodynamics (QCD) sector that couples to the standard model (SM) through a scalar mediator. The scalar mediator decays into an SM quark and a dark sector quark. As the dark sector quark showers and hadronizes, it produces long-lived dark mesons that subsequently decay into SM particles, resulting in a jet, known as an emerging jet, with multiple displaced vertices. This search looks for pair production of the scalar mediator at the LHC, which yields events with two SM jets and two emerging jets at leading order. The results are interpreted using two dark sector models with different flavor structures, and exclude mediator masses up to 1950 (1950) GeV for an unflavored (flavor-aligned) dark QCD model. The unflavored results surpass a previous search for emerging jets by setting the most stringent mediator mass exclusion limits to date, while the flavor-aligned results provide the first direct mediator mass exclusion limits to date

    Observation of the J/ψ -> μ+ μ- μ+ μ- decay in proton-proton collisions at 13 TeV

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    The Formula Presented decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of Formula Presented. Normalizing to the Formula Presented decay mode leads to a branching fraction of Formula Presented, a value that is consistent with the standard model prediction
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