47 research outputs found

    Measurement of the CP-violating phase ϕs_{s} in the B0^{0}s_{s}→J/ψ φ(1020) →μ⁺μ⁻K⁺K⁻ channel in proton-proton collisions at √s = 13 TeV

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    Observation of electroweak production of Wγ with two jets in proton-proton collisions at √s = 13 TeV

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    A first observation is presented for the electroweak production of a W boson, a photon, and two jets in proton-proton collisions. The W boson decays are selected by requiring one identified electron or muon and an imbalance in transverse momentum. The two jets are required to have a high dijet mass and a large separation in pseudorapidity. The measurement is based on data collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb1^{-1}. The observed (expected) significance for this process is 4.9 (4.6) standard deviations. After combining with previously reported CMS results at 8 TeV, the observed (expected) significance is 5.3 (4.8) standard deviations. The cross section for the electroweak Wγjj_{γjj} production in a restricted fiducial region is measured as 20.4 +/- 4.5 fb and the total cross section for Wγ_{γ} production in association with 2 jets in the same fiducial region is 108 +/- 16 fb. All results are in good agreement with recent theoretical predictions. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-8 effective field theory operators

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

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    Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at s=13 TeV

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    The first measurements of production cross sections of polarized same-sign W±W±boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137fb−1. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±W±scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88)fbis set on the production cross section for longitudinally polarized same-sign W±W±boson pairs. The electroweak production of same-sign W±W±boson pairs with at least one of the Wbosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.SCOAP

    Broadband two-layer shorted patch antenna with low cross-polarisation

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    The design and experimental results of a new configuration two-layer shorted square microstrip antenna with low cross-polarisation are described. The antenna has a bandwidth of 11 centred around 1.975GHz with a gain of 8.6dB, and exhibits better than -13dB cross-polarisation levels in the H-plane. The computed and measured results of the co-planar configuration of the structure are compared with its new two-layer stacked configuration

    Stacked shorted microstrip antenna for low cross polarization and wide-band

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    A novel structure to improve the cross-polarization characteristics of the shorted square microstrip antenna is presented. The square-ring patch is used as a parasitic element in the stacked position to tune the input impedance, resonant frequency, cross polarization, and bandwidth of the shorted square microstrip antenna. As a result, 11% bandwidth and better than - 14.5 dB cross-polarization levels have been achieved. The theoretical results are compared with the experimental results. © 2001 John Wiley & Sons, Inc

    High pressure electrical measurements on Ge-Te-Se glasses

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    Electrical resistivity measurements have been carried out on bulk Ge-Te-Se glasses in a Bridgman anvil system. The resistivity of the Ge-Te-Se samples is found to decrease continuously with increasing pressure, with the metallization occurring around 8GPa. Ge20TexSe80-x glasses (10 ⤠x ⤠50) with the mean co-ordination number Zav = 2.4 exhibit a plateau in resistivity up to about 4 GPa pressure, followed by a continuous decrease to metallic values. On the other hand, Ge10TexSe90-x glasses (10 ⤠x ⤠40) having Zav = 2.2, exhibit a smaller plateau (only up to 1 GPa), followed by a decrease in resistivity with pressure. This subtle difference in the high pressure resistivity of Ge-Te-Se glasses with Zav < 2.4 and Zav ⥠2.4 can be associated with the changes in the local structure of the chalcogenide glasses with composition

    Thermal crystallization behaviour of Ge-Te-Se glasses

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    Ge10Te90-xSex (50 ⤠x ⤠70) and Ge20Te80-xSex (x = 30, 50) glasses have been prepared by melt-quenching. The thermal crystallization behaviour of these samples has been studied by Differential Scanning Calorimetry (DSC), in order to characterise these glasses for memory-threshold switching applications. It is found that Ge10Te90-xSex glasses have higher thermal stability and are more stable against devitrification. These samples may be suitable for threshold switching devices. Ge20Te80-xSex glasses, on the other hand, phase separate on heating and exhibit a double stage crystallization. Based on this, it can be expected that Ge20Te80-xSex samples will show memory behaviour. The activation energy for thermal crystallization of a representative Ge10Te40Se50 glass belonging to the Ge10Te90-xSex series has been found by the Kissinger's method to be 0.92 eV. The value of the activation energy obtained also indicates that Ge10Te90-xSex samples are less prone to devitrification and more suitable for threshold behaviour

    Threshold electrical switching in As45Te55-xInx and As50Te50-xInx glasses

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    The electrical switching behaviour of As45Te55-x Inx (5 ≤ x ≤ 15) and As50Te50-xInx (2.5 ≤ x ≤ 11.5) has been studied over a wide range of compositions. These glasses are found to exhibit threshold switching. The composition dependence of switching voltage (Vt) has been found to exhibit a change in slope and a local minimum at compositions x = 10 and 12.5 for As45Te55-xInx and x = 7.5 and 10.8 for As50Te55-xInx, respectively. The slope change in Vt verses x and the local minimum have been identified using two network topological effects, namely the rigidity percolation threshold and the chemical threshold

    Threshold electrical switching in bulk As-Te-In glasses: Composition dependence and topological effects

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    The current-voltage (I-V) characteristics and electrical switching behaviours of As40Te60-xInx (5 ≤ x ≤ 16.5), As35Te65-xInx (10 ≤ x ≤ 19) and As30Te70-xInx (12.5 ≤ x ≤ 21.5) have been studied over wide ranges of indium concentrations x and average coordination numbers . All the glasses studied show a threshold switching behaviour. Further, the composition dependence of the switching field is found to exhibit a distinct change in slope at = 2.65 and a local minimum at around = 2.69. These results indicate the possibility that rigidity percolation occurs at around = 2.65 and chemical threshold around = 2.69
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