335 research outputs found

    Sensor Approach for Brain Pathophysiology of Freezing of Gait in Parkinson\u27s Disease Patients

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    Parkinson\u27s Disease (PD) affects over 1% of the population over 60 years of age and is expected to reach 1 million in the USA by the year 2020, growing by 60 thousand each year. It is well understood that PD is characterized by dopaminergic loss, leading to decreased executive function causing motor symptoms such as tremors, bradykinesia, dyskinesia, and freezing of gait (FoG) as well as non-motor symptoms such as loss of smell, depression, and sleep abnormalities. A PD diagnosis is difficult to make since there is no worldwide approved test and difficult to manage since its manifestations are widely heterogeneous among subjects. Thus, understanding the patient subsets and the neural biomarkers that set them apart will lead to improved personalized care. To explore the physiological alternations caused by PD on neurological pathways and their effect on motor control, it is necessary to detect the neural activity and its dissociation with healthy physiological function. To this effect, this study presents a custom ultra-wearable sensor solution, consisting of electroencephalograph, electromyograph, ground reaction force, and symptom measurement sensors for the exploration of neural biomarkers during active gait paradigms. Additionally, this study employed novel de-noising techniques for dealing with the motion artifacts associated with active gait EEG recordings and compared time-frequency features between a group of PD with FoG and a group of age-matched controls and found significant differences between several EEG frequency bands during start and end of normal walking (with a p\u3c0.05)

    Strategies and performance of the CMS silicon tracker alignment during LHC Run 2

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    The strategies for and the performance of the CMS silicon tracking system alignment during the 2015–2018 data-taking period of the LHC are described. The alignment procedures during and after data taking are explained. Alignment scenarios are also derived for use in the simulation of the detector response. Systematic effects, related to intrinsic symmetries of the alignment task or to external constraints, are discussed and illustrated for different scenarios

    Measurement of the double-differential inclusive jet cross section in proton-proton collisions at s\sqrt{s} = 5.02 TeV

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    International audienceThe inclusive jet cross section is measured as a function of jet transverse momentum pTp_\mathrm{T} and rapidity yy. The measurement is performed using proton-proton collision data at s\sqrt{s} = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb1^{-1}. The jets are reconstructed with the anti-kTk_\mathrm{T} algorithm using a distance parameter of RR = 0.4, within the rapidity interval y\lvert y\rvert<\lt 2, and across the kinematic range 0.06 <\ltpTp_\mathrm{T}<\lt 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling αS\alpha_\mathrm{S}

    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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    International audienceMeasurements 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 nonresonant Higgs boson pair production in final state with two bottom quarks and two tau leptons in proton-proton collisions at <math altimg="si1.svg"><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>13</mn><mtext> TeV</mtext></math>

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    International audienceA search for the nonresonant production of Higgs boson pairs (HH ) via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two tau leptons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of s=13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Events in which at least one tau lepton decays hadronically are considered and multiple machine learning techniques are used to identify and extract the signal. The data are found to be consistent, within uncertainties, with the standard model (SM) predictions. Upper limits on the HH production cross section are set to constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to 3.3 (5.2) times the SM prediction for the inclusive HH cross section and to 124 (154) times the SM prediction for the vector boson fusion HH cross section. At 95% confidence level, the Higgs field self-coupling is constrained to be within −1.7 and 8.7 times the SM expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within −0.4 and 2.6 times the SM expectation

    Measurement of the <math altimg="si1.svg"><mi mathvariant="normal">t</mi><mover accent="true"><mrow><mi mathvariant="normal">t</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></math> charge asymmetry in events with highly Lorentz-boosted top quarks in pp collisions at <math altimg="si2.svg"><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>13</mn></math> TeV

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    International audienceThe measurement of the charge asymmetry in top quark pair events with highly Lorentz-boosted top quarks decaying to a single lepton and jets is presented. The analysis is performed using proton-proton collisions at s=13TeV with the CMS detector at the LHC and corresponding to an integrated luminosity of 138 fb−1. The selection is optimized for top quarks produced with large Lorentz boosts, resulting in nonisolated leptons and overlapping jets. The top quark charge asymmetry is measured for events with a tt¯ invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured top quark charge asymmetry of (0.42−0.69+0.64)% is in good agreement with the standard model prediction at next-to-next-to-leading order in quantum chromodynamic perturbation theory with next-to-leading-order electroweak corrections. The result is also presented for two invariant mass ranges, 750–900 and &gt;900GeV

    Search for a new resonance decaying into two spin-0 bosons in a final state with two photons and two bottom quarks in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceA search for a new boson X is presented using CERN LHC proton-proton collision data collected by the CMS experiment at s\sqrt{s} = 13 TeV in 2016-2018, and corresponding to an integrated luminosity of 138 fb1^{-1}. The resonance X decays into either a pair of Higgs bosons HH of mass 125 GeV or an H and a new spin-0 boson Y. One H subsequently decays to a pair of photons, and the second H or Y, to a pair of bottom quarks. The explored mass ranges of X are 260-1000 GeV and 300-1000 GeV, for decays to HH and to HY, respectively, with the Y mass range being 90-800 GeV. For a spin-0 X hypothesis, the 95% confidence level upper limit on the product of its production cross section and decay branching fraction is observed to be within 0.90-0.04 fb, depending on the masses of X and Y. The largest deviation from the background-only hypothesis with a local (global) significance of 3.8 (2.8) standard deviations is observed for X and Y masses of 650 and 90 GeV, respectively. The limits are interpreted using several models of new physics

    Measurement of simplified template cross sections of the Higgs boson produced in association with W or Z bosons in the H bb \to \mathrm{b}\overline{\mathrm{b}} decay channel in proton-proton collisions at s= \sqrt{s}= 13 TeV

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    Differential cross sections are measured for the standard model Higgs boson produced in association with vector bosons (W, Z) and decaying to a pair of b quarks. Measurements are performed within the framework of the simplified template cross sections. The analysis relies on the leptonic decays of the W and Z bosons, resulting in final states with 0, 1, or 2 electrons or muons. The Higgs boson candidates are either reconstructed from pairs of resolved b-tagged jets, or from single large distance parameter jets containing the particles arising from two b quarks. Proton-proton collision data at s= \sqrt{s}= 13 TeV, collected by the CMS experiment in 2016--2018 and corresponding to a total integrated luminosity of 138 fb1 ^{-1} , are analyzed. The inclusive signal strength, defined as the product of the observed production cross section and branching fraction relative to the standard model expectation, combining all analysis categories, is found to be μ= \mu= 1.15 0.20+0.22 ^{+0.22}_{-0.20} . This corresponds to an observed (expected) significance of 6.3 (5.6) standard deviations.Differential cross sections are measured for the standard model Higgs boson produced in association with vector bosons (W, Z) and decaying to a pair of b quarks. Measurements are performed within the framework of the simplified template cross sections. The analysis relies on the leptonic decays of the W and Z bosons, resulting in final states with 0, 1, or 2 electrons or muons. The Higgs boson candidates are either reconstructed from pairs of resolved b-tagged jets, or from single large distance parameter jets containing the particles arising from two b quarks. Proton-proton collision data at s\sqrt{s} = 13 TeV, collected by the CMS experiment in 2016-2018 and corresponding to a total integrated luminosity of 138 fb1^{-1}, are analyzed. The inclusive signal strength, defined as the product of the observed production cross section and branching fraction relative to the standard model expectation, combining all analysis categories, is found to be μ\mu = 1.150.20+0.22^{+0.22}_{-0.20}. This corresponds to an observed (expected) significance of 6.3 (5.6) standard deviations

    Search for Higgs Boson and Observation of Z Boson through their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at s\sqrt{s} =13 TeV

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    A search for the standard model (SM) Higgs boson (H) produced with transverse momentum greater than 450 GeV and decaying to a charm quark-antiquark (ccˉ\mathrm{c\bar{c}}) pair is presented. The search is performed using proton-proton collision data collected at s\sqrt{s} = 13 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb1^{-1}. Boosted H \toccˉ\mathrm{c\bar{c}} decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z \toccˉ\mathrm{c\bar{c}} decay process, which is observed in association with jets at high pTp_\mathrm{T} for the first time with a signal strength of 1.00 0.14+0.17_{-0.14}^{+0.17} (syst) ±\pm 0.08 (theo) ±\pm 0.06 (stat), defined as the ratio of the observed process rate to the standard model expectation. The observed (expected) upper limit on σ\sigma(H) B\mathcal{B}(H \toccˉ\mathrm{c\bar{c}}) is set at 47 (39) times the SM prediction at 95% confidence level

    Search for Higgs boson decay to a charm quark-antiquark pair in proton-proton collisions at s\sqrt{s} = 13 TeV

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    International audienceA search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H \toccˉ\mathrm{c\bar{c}}, produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at s\sqrt{s} = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb1^{-1}. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z \toccˉ\mathrm{c\bar{c}} in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ\sigma(VH)B \mathcal{B}(H \toccˉ\mathrm{c\bar{c}}) is 0.94 (0.50 0.15+0.22^{+0.22}_{-0.15}) pb at 95% confidence level (CL), corresponding to 14 (7.6 2.3+3.4^{+3.4}_{-2.3}) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κc\kappa_\mathrm{c}, the observed (expected) 95% CL interval is 1.1 <\lt κC\vert\kappa_\mathrm{C}\vert <\lt 5.5 (κc\vert\kappa_\mathrm{c}\vert <\lt 3.4), the most stringent constraint to date
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