508 research outputs found

    Giant Pleomorphic Adenoma of Parotid Gland: A Rare Cytological Diagnosis

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    Pleomorphic adenoma is the most common salivary gland neoplasm, which affects both major and minor salivary glands. It is also the most common neoplasm arising in the parotid. In minor salivary glands, it most commonly involves the palate and rarely involves the lips, cheek and gingiva. It is also called Benign Mixed Tumour (BMT), since it is composed of a variable amount of epithelial and mesenchymal elements. Diagnostic modalities include Ultrasonography (USG), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). MRI provided the most precise structural information of the tumour as well as surrounding structures. A 60-year-old female presented with a massive right-sided infra-auricular swelling, since 20 years. On Contrast Enhanced Computed Tomography (CECT), a huge lobular exophytic lesion with thin enhancing septation and few calcific foci was visualised in the right parotid region. The Fine Needle Aspiration Cytology (FNAC) yielded the diagnosis of Pleomorphic Adenoma (PA). Giant PA with an indolent course is a rare entity in itself. This is a case of giant PA of the parotid gland growing insidiously over a period of 20 years

    Search for high-mass exclusive γγ\gamma\gamma\to WW and γγ\gamma\gamma\to ZZ production in proton-proton collisions at s\sqrt{s} = 13 TeV

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    A search is performed for exclusive high-mass γγ\gamma\gamma\to WW and γγ\gamma\gamma\to ZZ production in proton-proton collisions using intact forward protons reconstructed in near-beam detectors, with both weak bosons decaying into boosted and merged jets. The analysis is based on a sample of proton-proton collisions collected by the CMS and TOTEM experiments at s \sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 100 fb1^{−1}. No excess above the standard model background prediction is observed, and upper limits are set on the pp → pWWp and pp → pZZp cross sections in a fiducial region defined by the diboson invariant mass m(VV) > 1 TeV (with V = W, Z) and proton fractional momentum loss 0.04 < ξξ < 0.20. The results are interpreted as new limits on dimension-6 and dimension-8 anomalous quartic gauge couplings.[graphic not available: see fulltext

    Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at s \sqrt{s} = 13 TeV

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    Measurements of the inclusive and normalised differential cross sections are presented for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data used were recorded with the CMS detector at the LHC during 2016–2018, and correspond to an integrated luminosity of 138 fb1^{−1}. Events containing one electron and one muon in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events is used to separate the signal from the dominant tt \textrm{t}\overline{\textrm{t}} background. A cross section of 79.2±0.9(stat)8.0+7.7(syst)±1.2(lumi) 79.2\pm 0.9{\left(\textrm{stat}\right)}_{-8.0}^{+7.7}\left(\textrm{syst}\right)\pm 1.2\left(\textrm{lumi}\right) pb is obtained, consistent with the predictions of the standard model. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requirement of exactly one jet coming from the fragmentation of a bottom quark. The resulting distributions are unfolded to particle level and agree with the predictions at next-to-leading order in perturbative quantum chromodynamics.[graphic not available: see fulltext

    Search for pair production of vector-like quarks in leptonic final states in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016–2018, with an integrated luminosity of 138 fb1^{−1}. Events are separated into single-lepton, same-sign charge dilepton, and multi-lepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for TT \textrm{T}\overline{\textrm{T}} production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for BB \textrm{B}\overline{\textrm{B}} production with B quark decays to tW.[graphic not available: see fulltext

    Search for top squarks in the four-body decay mode with single lepton final states in proton-proton collisions at s= \sqrt{s}= 13 TeV

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    A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (t~1 \tilde{\mathrm{t}}_{1} ), is presented. The search targets the four-body decay of the t~1 \tilde{\mathrm{t}}_{1} , which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (χ~10 \tilde{\chi}_{1}^{0} ), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb1 ^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(t~1) m(\tilde{\mathrm{t}}_{1}) and m(χ~10) m(\tilde{\chi}_{1}^{0}) . The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(t~1)m(χ~10)= m(\tilde{\mathrm{t}}_{1}) - m(\tilde{\chi}_{1}^{0}) = 10 and 80 GeV, respectively.A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (t1 {\overset{\sim }{\textrm{t}}}_1 ), is presented. The search targets the four-body decay of the t1 {\overset{\sim }{\textrm{t}}}_1 , which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (χ10 {\overset{\sim }{\chi}}_1^0 ), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb1^{−1} of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(t1 {\overset{\sim }{\textrm{t}}}_1 ) and m(χ10 {\overset{\sim }{\chi}}_1^0 ). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(t1 {\overset{\sim }{\textrm{t}}}_1 ) − m(χ10 {\overset{\sim }{\chi}}_1^0 ) = 10 and 80 GeV, respectively.[graphic not available: see fulltext]A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark (t~1\tilde{\mathrm{t}}_1), is presented. The search targets the four-body decay of the t~1\tilde{\mathrm{t}}_1, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino (χ~10\tilde{\chi}^0_1), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb1^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between m(t~1)m(\tilde{\mathrm{t}}_1) and m(χ~10)m(\tilde{\chi}^0_1). The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for m(t~1)m(χ~10m(\tilde{\mathrm{t}}_1) - m(\tilde{\chi}^0_1) = 10 and 80 GeV, respectively

    Search for nonresonant Higgs boson pair production in the four leptons plus twob jets final state in proton-proton collisions at s \sqrt{s} = 13 TeV

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    The first search for nonresonant production of Higgs boson pairs (HH) with one H decaying into four leptons and the other into a pair of b quarks is presented, using proton-proton collisions recorded at a center-of-mass energy of s \sqrt{s} = 13 TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 138 fb1^{−1}. A 95% confidence level upper limit of 32.4 is set on the signal strength modifier μ, defined as the ratio of the observed HH production rate in the HHZZbb4bb \textrm{HH}\to {\textrm{ZZ}}^{\ast}\textrm{b}\overline{\textrm{b}}\to 4\ell \textrm{b}\overline{\textrm{b}} decay channel to the standard model (SM) expectation. Possible modifications of the H trilinear coupling λHHH_{HHH} with respect to the SM value are investigated. The coupling modifier κλ_{λ}, defined as λHHH_{HHH} divided by its SM prediction, is constrained to be within the observed (expected) range −8.8 (−9.8) < κλ_{λ}< 13.4 (15.0) at 95% confidence level.[graphic not available: see fulltext

    Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at s \sqrt{s} = 13 TeV

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    The measurements of the inclusive and differential fiducial cross sections of the Higgs boson decaying to a pair of photons are presented. The analysis is performed using proton-proton collisions data recorded with the CMS detector at the LHC at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 137 fb1^{−1}. The inclusive fiducial cross section is measured to be σfid=73.45.3+5.4(stat)2.2+2.4(syst) {\sigma}_{\textrm{fid}}={73.4}_{-5.3}^{+5.4}{\left(\textrm{stat}\right)}_{-2.2}^{+2.4}\left(\textrm{syst}\right) fb, in agreement with the standard model expectation of 75.4 ± 4.1 fb. The measurements are also performed in fiducial regions targeting different production modes and as function of several observables describing the diphoton system, the number of additional jets present in the event, and other kinematic observables. Two double differential measurements are performed. No significant deviations from the standard model expectations are observed.[graphic not available: see fulltext

    Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer

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    International audienceThe Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb1^{-1} in proton-proton (pp) collisions at the LHC at 13 TeV (Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider

    Search for a charged Higgs boson decaying into a heavy neutral Higgs boson and a W boson in proton-proton collisions at s=\sqrt{s} = 13 TeV

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    A search for a charged Higgs boson H~±{\mathrm{\tilde{H}^{\pm}}} decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016-2018 at s=\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H~±{\mathrm{\tilde{H}^{\pm}}} in the mass range of 300-700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H~±{\mathrm{\tilde{H}^{\pm}}} mass of 300 GeV to 0.019 pb for a mass of 700 GeV. These are the first limits on H~±{\mathrm{\tilde{H}^{\pm}}} production in the H~±HW±{\mathrm{\tilde{H}^{\pm}}} \to \mathrm{H} \mathrm{W^{\pm}} decay channel at the LHC.A search for a charged Higgs boson H±^{±} decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016–2018 at s \sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{−1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H±^{±} in the mass range of 300–700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H±^{±} mass of 300 Ge V to 0.019 pb for a mass of 700 GeV. These are the first limits on H±^{±} production in the H±^{±}→ HW±^{±} decay channel at the LHC.[graphic not available: see fulltext]A search for a charged Higgs boson H±^\pm decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016-2018 at s\sqrt{s} = 13 TeV, corresponding to an integrated luminosity of 138 fb1^{-1}. The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H±^\pm in the mass range of 300-700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H±^\pm mass of 300 GeV to 0.019 pb for a mass of 700 GeV. These are the first limits on H±^\pm production in the H±^\pm \to HW±^\pm decay channel at the LHC
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