Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at root s=13 TeV

Abstract:A measurement of the top quark mass is performed using a data sample en-riched with single top quark events produced in thetchannel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb−1, recorded at√s= 13TeV by the CMS experiment at the LHC in 2016. Candidate events are selectedby requiring an isolated high-momentum lepton (muon or electron) and exactly two jets,of which one is identified as originating from a bottom quark. Multivariate discriminantsare designed to separate the signal from the background. Optimized thresholds are placedon the discriminant outputs to obtain an event sample with high signal purity. The topquark mass is found to be172.13+0.76−0.77GeV, where the uncertainty includes both the sta-tistical and systematic components, reaching sub-GeV precision for the first time in thisevent topology. The masses of the top quark and antiquark are also determined separatelyusing the lepton charge in the final state, from which the mass ratio and difference aredetermined to be0.9952+0.0079−0.0104and0.83+1.79−1.35GeV, respectively. The results are consistentwithCPTinvariance

Search for a heavy Higgs boson decaying into two lighter Higgs bosons in the tau tau bb final state at 13 TeV

A search for a heavy Higgs boson H decaying into the observed Higgs boson h with a mass of 125 GeV and another Higgs boson h(S) is presented. The h and h(S) bosons are required to decay into a pair of tau leptons and a pair of b quarks, respectively. The search uses a sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137 fb(-1). Mass ranges of 240-3000 GeV for m(H) and 60-2800 GeV for m(hS) are explored in the search. No signal has been observed. Model independent 95% confidence level upper limits on the product of the production cross section and the branching fractions of the signal process are set with a sensitivity ranging from 125 fb (for m(H) = 240 GeV) to 2.7 fb (for m(H) = 1000 GeV). These limits are compared to maximally allowed products of the production cross section and the branching fractions of the signal process in the next-to-minimal supersymmetric extension of the standard model.Peer reviewe

Prise en charge de l'hypotension sous anesthésie par développement d'un moniteur de mesure non invasive de la pression artérielle et par l'élaboration d'un modèle PK/PD de la noradrénaline

Introperative hypotension (IOH) is common and responsible for damage to myocardium, kidneys and brain tissue as well as increased mortality. Proactive management of IOH has been shown to prevent complications. Remaining obstacles to the effective treatment of IOH are the lack of reliable non-invasive monitoring as well as tools to personalize drug administration to treat hypotension. In order to monitor intraoperative blood pressure, discontinuous pressure cuff measurements seem to be insufficient today. Monitoring should be both, continuous and non-invasive. We have developed algorithms based on physiology to allow the estimation of the mean arterial pressure in real time, beat to beat, using readily available standard monitoring equipment. Treatment of IOH is nowadays largely based on vasopressors. Low-dose dilute norepinephrine has established itself as a de facto standard treatment in this domain in large parts of the world. It is a powerful drug with a short half-life and a narrow therapeutic window. No current standard for the use of low dose norepinephrine exists today and she lack of standardized drug use can lead to accidents. We developed a pharmacokinetic/pharmacodynamic (PK/PD) model that allows individualized dose calculation and can be used as a basis for a targeted controled infusion. The joint use of physiologic models for blood pressure monitoring and patient centered drug delivery could eventually automate the management of IOH and result in public health benefit.L'hypotension artérielle sous anesthésie (IOH) est un phénomène fréquent. Des études récentes ont identifié l'IOH comme responsable de dommages myocardiques, d'insuffisance rénale aiguë, d'hypoperfusion cérébrale augmentant ainsi la morbi-mortalité post-opératoire. La population de patients devient de plus en plus âgée et de plus en plus fragile, or les patients les plus fragiles sont le plus exposés au risque d'IOH et sont ceux qui la tolèrent le moins bien ces épisodes. Ils sont exposés à une morbidité accrue, des défaillances d'organes et des complications post-opératoires qui peuvent avoir des séquelles à long terme dans de nombreux cas. Il a été montré dans la littérature qu'une prise en charge agressive de cette hypotension permet d'éviter un certain nombre de complications post-opératoires. En effet, les la gravité des souffrances d'organes est à la fois liée à la profondeur de l'hypotension comme à la durée d'hypotension. Un traitement avec un objectif de pression artérielle permet d'en réduire l'exposition. Les moyens thérapeutiques efficaces pour traiter cette hypotension existent, notamment avec les médicaments vasopresseurs, et la mise en oeuvre de cette prise en charge à large échelle se traduirait sans doute par un bénéfice de santé publique. Nous avons cependant identifié deux freins à l'application de cette prise en charge aujourd'hui, d'un côté un manque de monitorage et de l'autre côté des difficultés de mise en place du traitement. La gravité de l'hypotension étant dose dépendante, le monitorage joue un rôle clé. Un brassard à tension permettant une mesure discontinue semble aujourd'hui insuffisant et un monitorage continu paraît nécessaire. Il ne paraît cependant pas raisonnable de proposer systématiquement un monitorage invasif pour des patients sans pathologie sévère sous-jacente pour des chirurgie de risque faible ou intermédiaire. Par conséquent, le monitorage doit être continu et non-invasif. Nous avons mis au point, en se basant sur des mécanismes physiologiques, une série d'algorithmes permettant l'estimation en temps réel, battement par battement, de la pression artérielle moyenne en utilisant le monitorage standard préexistant, notamment la photopléthysmographie, permettant de cette manière une utilisation systématique sans surcoût. Le traitement de l'hypotension sous anesthésie est aujourd'hui largement basé sur des médicaments vasopresseurs. Parmi ceux-là, la noradrénaline diluée faiblement dosée s'est très rapidement établie comme un standard de facto sur les 5 dernières années. Cependant, l'utilisation de cette drogue n'est pas toujours aisée. En effet, il s'agit d'un médicament puissant avec une demie vie courte et une fenêtre thérapeutique étroite. L'absence de standardisation quant à l'utilisation peut exposer à des accidents d'utilisation et la grande variabilité interindividuelle rend difficile l'ajustement de la dose nécessaire. Nous avons développé un modèle pharmacocinétique/pharmacodynamique (PK/PD) permettant un calcul de dose individualisé par patient et pouvant servir de base pour une administration en objectif de concentration. L'administration de la noradrénaline en objectif de concentration est une méthode de choix pour uniformiser et simplifier les prises en charge tout en évitant des erreurs de dose et des fluctuations. L'incorporation de ces deux modèles, l'un de monitorage, l'autre de traitement pharmacologique, en boucle fermée pourrait à terme automatiser la prise en charge de l'hypotension sous anesthésie

CoOx thin film deposited by CVD as efficient water oxidation catalyst: change of oxidation state in XPS and its correlation to electrochemical activity

To reduce energy losses in water electrolysers a fundamental understanding of the water oxidation reaction steps is necessary to design efficient oxygen evolution catalysts. Here we present CoOx/Ti electrocatalytic films deposited by thermal and plasma enhanced chemical vapor deposition (CVD) onto titanium substrates. We report electrochemical (EC), photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The electrochemical behavior of the samples was correlated with the chemical and electronic structure by recording XPS spectra before and after each electrochemical treatment (conditioning and cyclovoltammetry). The results show that the electrochemical behavior of CoOx/Ti strongly depends on the resulting electronic structure and composition. The thermal deposition leads to the formation of a pure Co(II)Ox which transforms to a mixed Co(II)Co(III)Ox during the OER. This change in oxidation state is coupled with a decrease in overpotential from η = 0.57 V to η = 0.43 V at 5 mA cm−2. Plasma deposition in oxygen leads to a Co(III)-dominated mixed CoOx, that has a lower onset potential as deposited due to a higher Co(III) content in the initial deposited material. After the OER XPS results of the CoOx/Ti indicate a partial formation of hydroxides and oxyhydroxides on the oxide surface. Finally the plasma deposition in air, results in a CoOxOH2 surface, that is able to completely oxidizes during OER to an oxyhydroxide Co(III)OOH. With the in situ formed CoOOH we present a highly active catalyst for the OER (η = 0.34 at 5 mA cm−2; η = 0.37 V at 10 mA cm−2)

Norepinephrine reduces arterial compliance less than phenylephrine when treating general anesthesia-induced arterial hypotension

International audienceIntroduction: During general anesthesia, arterial hypotension is frequent and may be an important contributor to peri-operative morbidity. We assessed the effect of a 5µg bolus of Norepinephrine (NA) when compared with 50 µg bolus of Phenylephrine (PE) administered to treat hypotension during maintenance anesthesia, on MAP, derived cardiac output and arterial stiffness parameters. Methods: Patients scheduled for a neurosurgical procedure under general anesthesia were prospectively included. Monitoring included invasive blood pressure, esophageal Doppler and arterial tonometer used to estimate central aortic pressure with arterial stiffness parameters, such as augmentation index (Aix). After initial resuscitation, hypotensive episodes were corrected by a bolus administration of NA or PE in a peripheral venous line. Results: There were 269 bolus administrations of vasopressors (149 NA, 120 PE) in 47 patients with no adverse effects detected. A decrease in stroke volume (SV) was observed with PE compared with NA (-18±9% vs -14±7%, p<0.001). This decrease was associated with an increase in Aix, which was greater for PE than for NA (+10±8% vs +6±6%, p<0.0001), and a decrease in total arterial compliance greater for PE compared to NA (Ctot=SV/Central Pulse Pressure) (-35±9% vs. -29±10%, p<0.001). Discussion: This study suggests that 5 µg of NA administered as a bolus in a peripheral venous line could treat general-anesthesia-induced arterial hypotension with a smaller decrease in SV and arterial compliance when compared to PE