37 research outputs found

    Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

    Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

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    Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values

    The Physics of the B Factories

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    Complexes of Methyl-Tin and -Lead Halides with Substituted Pyridine N-Oxides

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    Complexes of some methyl-tin and -lead halides with a range of 4-substituted pyridine N-oxides have been prepared and characterized. The fluctuations in v(N-O) and in J(CH3-M) have been examined as a function of substituent, and the resonance positions of ring protons in the proton spectra are discussed

    Preparation and spectroscopic studies of tri(p-tolyl)-tin(IV) compounds. X-ray crystal structure of the quinoline-N-oxide adduct of tri(p-tolyl)tin(IV) bromide

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    Syntheses and spectroscopic data are presented for R3SnIV compounds, where R is predominantly p-tolyl, of the following types: R3SnX·L (X = Cl, Br or NCS; L = neutral, monodentate oxygen donor), R3SnY (YH = 1,2,4-triazole, N-phenyl-N-benzoylhydroxamic, succinanilic, levulinic and hippuric acids) and [R3SnL2]+ [Ph4B]− (L = neutral, monodentate or 1/2 bidentate oxygen donor). The spectroscopic data (IR and Mössbauer) are interpreted in terms of discrete or weakly polymeric trigonal bipyramidal structures, with the R3Sn skeleton forming the equatorial plane for most of the compounds. A cis-geometry is inferred for the case where the anionic residue is the chelating N-phenyl-N-benzoylhydroxamate ligand, while a meridional geometry is predicted for the cationic complexes involving the chelating ligans, 2,2′-bipyridine N,N′-dioxide and ethylenebis(diphenylphosphine oxide). Both the 13C NMR and the IR data suggest that the Lewis acceptor strength falls in the order (p-ClC6H4)3Sn > (C6H5Sn> (p-MeC6H4)3Sn. Crystals of (p-tolyl)3SnBr· quinoline-N-oxide are triclinic, space group P, with a 10.245(4), b 10.862(2), c 13.153(5) Å, α 84.10(2), β 68.39(3), γ 80.88(3)°. The structure was refined to R = 0.070 for 4548 observed Mo-Kα reflections and comprises independent, non-interacting molecules which are pentacoordinate at tin. The quinoline-N-oxide ligand is coordinated apically to tin in the trigonal-bipyramidal unit; the three tolyl rings occupy the trigonal plane but the tin atom is displaced by 0.17(1) Å towards the other apical bromide ligand
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