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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Développement de nanovecteurs polymériques et lipidiques fonctionnalisés par des anticorps pour cibler des cellules cancéreuses / Development of antibody functionalized polymeric and lipidic nanoparticles for targeting cancer cells

Wan, Yali 20 December 2012 (has links)
Ce travail, qui fait partie d’un projet européen, « NANOTHER », est focalisé sur la fonctionnalisation de nanoparticules polymériques et lipidiques fonctionnalisées par des anticorps Herceptine® pour cibler des cellules du cancer du sein HER2+. Deux stratégies de fonctionnalisation ont été étudiées : une a reposé sur l’utilisation de protéines de fusion, l’Anx5-ZZ, composée d’Annexine A5 et deux domaines Z homologues de la protéine A de Staphylococcus aureus qui peuvent se fixer des anticorps d’une manière orientée par leur fragment cristallisable ; l’autre a porté sur le couplage direct d’anticorps modifiés pour exposer des groupes sulfhydryles aux nanoparticules exposant des groupes maléimides.La première partie concerne le développement d’un agent de ciblage simplifié du complexe l’Anx5-ZZ-anticorps, à savoir l’Anx5-scFv (single-chain variable fragment). Puisque la cible n’avait pas été décidée au début de ce travail, deux scFvs ont été utilisé comme système modèle. L’expression de protéines de fusion a été essayée chez Escherichia Coli avec différentes constructions de protéines de fusion, différentes conditions d’expression et différentes souches bactériennes. Toutes les protéines sont soient agrégées soient non surexprimées.La deuxième partie consiste à fonctionnaliser les polymersomes par l’Herceptine® via l’Anx5-ZZ. D’abord, nous avons validé une méthode de modification de la surface de polymersome pour présenter des groupes maléimides. Ensuite, le couplage covalent de l’Anx5(SH)-ZZ aux polymersomes-maléimide a été réalisé et quantifié. Nous avons obtenu maximum 30 Anx5-ZZ par polymersome. Puis, la liaison d’affinité d’anticorps aux polymersomes-Anx5-ZZ a été caractérisée, réalisée et quantifiée. Pour 30 Anx5-ZZ par polymersome, nous avons 60 Herceptine® par polymersome. Cependant, l’efficacité de ciblage de ces systèmes est très faible.La troisième partie consiste à fonctionnaliser les liposomes par l’Herceptine® via couplage direct. Tout d’abord, la modification de l’Herceptine® pour présenter des groupes SH a été caractérisée et contrôlée. Ensuite, le couplage covalent d’Herceptine®-SH aux liposomes-maléimides a été réalisé et quantifié. L’étude de ciblage montre que les liposomes fonctionnalisés par une molécule d’Herceptine® sont capable de cibler les cellules HER2+. / This work, which is part of a European project "NANOTHER", focus on the functionalization of polymeric and lipidic nanoparticles by Herceptin® to target HER2+ cancer cells. Two functionalization strategies were studied: one was based on the use of a fusion protein, Anx5-ZZ, composed of Annexin A5 and two Z domains which are homologous with the protein A of Staphylococcus aureus that can bind antibodies by their crystallizable fragment in a oriented way; the other focused on the direct coupling of modified antibodies exposing sulfhydryl groups to nanoparticles exposing maleimid groups.The first part concerns the development of a targeting agent simplified from the Anx5-ZZ-antibody complex, namely Anx5-scFv (single-chain variable fragment). Since the target had not been decided at the beginning of this work, two scFvs were used as model system. The expression of fusion proteins was tested in Escherichia coli with different fusion protein constructions, different expression conditions and different bacterial strains. All proteins are either aggregated or non-overexpressed.The second part is to functionalize the polymersomes by Herceptin® via Anx5-ZZ. First, we validated a method for modifying the surface of polymersome to expose maleimid groups. Then, the covalent coupling of Anx5(SH)-ZZ to polymersomes-maleimid was performed and quantified. We obtained maximum 30 Anx5-ZZ per polymersome. Then, the affinity binding of antibodies to polymersomes-Anx5-ZZ was characterized, performed and quantified. For 30 Anx5-ZZ per polymersome, we have 60 Herceptin® per polymersome. However, the targeting efficiency of this system is very low.The third part consists in functionalizing the liposomes by Herceptin® via direct coupling. Firstly, the modification of Herceptin® to expose SH groups was characterized and controlled. Then, the covalent coupling of Herceptin®-SH to liposomes exposing maleimid groups was performed and quantified. The targeting study shows that liposomes functionalized with one Herceptin® are able to target HER2+ cells.
2

Evolução empírica da faixa de instabilidade das estrelas ZZ Ceti

Costa, Alex Fabiano Murillo da January 2007 (has links)
As estrelas ZZ Cetis, também chamadas de DAVs, são anãs brancas com atmosfera de hidrogênio que mostram variabilidade fotométrica. Neste trabalho buscamos estudar a pureza, a existência ou não de variáveis e estrelas constantes com mesmas Tef e log g, e definir com melhor precisão os contornos da faixa de instabilidade das estrelas ZZ Cetis. Para isto realizamos observações de séries temporais fotométricas para identificar novas estrelas do tipo ZZ Ceti, e também obtivemos espectros óticos para determinação dos parâmetros atmosféricos (Tef e log g), utilizando modelos atmosféricos com convecção descrita pela teoria de comprimento de mistura, com ML2/® = 0, 6. Ao longo deste trabalho identificamos 3 novas estrelas do tipo ZZ Ceti, WDJ0000−0046, WDJ2334+0103 e WDJ1650+3010, dentre 67 para as quais não encontramos variabilidade até o nosso limite de detecção, próximo de 2 mma. Além disto estudamos a distribuição de massa através de espectrosóoticos de 170 estrelas, assim como a comparação destes resultados com outros publicados na literatura. Também analisamos a distribuição de massa de outras amostras de espectrosóticos de anãs brancas: 2253 espectros do Sloan Digital Sky Survey e 449 espectros do Two Degree Field. Em todas distribuições estudadas, observamos um aumento na massa das estrelas da faixa de instabilidade e as mais frias, região de temperatura onde aumentam a convecção e o número de partículas neutras. O aumento de massa observado provavelmente não é real, e sim provocado pela forma como são aproximadas as interações de partículas ionizadas com o campo elétrico (efeito Stark) e de partículas neutras (Van der Walls), nos modelos de atmosfera. A razão pela qual não propomos que o aumento de massa seja real é que os mesmos parâmetros atmosféricos, quando determinados pelas cores fotométricas, não apresentam este aumento. Um resultado de nossa análise é que a faixa de instabilidade das estrelas ZZ Cetis, determinada através de espectrosóticos de alta razão sinal/ruído, contém apenas estrelas variáveis em seu interior. Face á descoberta de estrelas variáveis com amplitudes de 1,5 mma, previamente classificadas como não variáveis, será necessário um estudo mais profundo de todas as estrelas classificadas como não observadas como variáveis (NOV) até o momento, reduzindo os limites de detecção para a faixa de 1 mma, para definirmos com precisão as bordas da faixa de instabilidade das ZZ Cetis. / ZZ Ceti are hydrogen atmosphere white dwarf stars that show photometric variability. In this work we study the purity and define with better precision the borders of the instability strip of the ZZ Cetis stars. We obtained times series photometric observations to identify new ZZ Ceti stars, and optical spectra for the determination of the atmospheric (Teff and log g) parameters, using atmospheric models with convection described by mixing length theory with ML2/® = 0.6. We identified 3 new ZZ Ceti stars: WDJ0000−0046, WDJ2334+0103, and WDJ1650+3010, among 67 stars for which we detected no variability up to our detection limit about 2 mma. We analyzed the mass distribution of the 170 stars we observed with S/N ¸ 70 optical spectra. We also studied the mass distribution of other samples of white dwarfs, 2253 spectra of Sloan Digital Sky Survey and 449 spectra of the Two Degree Field. In all studied distributions, we observed an increase in the mass determined for the stars cooler than the instability strip. This apparent increase occurs in a region where there is an increase in the depth of convection and in the number of neutral particles. We propose the increase in mass is not real, but caused by the form the Stark and Van der Walls broadenings are estimated in the atmospheric models. The reason we do not trust the mass increase is that the determination of masses using photometric colors, for the same stars, do not show such increase. One result from our research is that we find no constant stars inside the instability strip when we consider only our high S/N spectra. Considering the recent discovery of variable stars with amplitudes down to 1.5 mma, previously classified as not variables, we deem it necessary to restudy all stars not observed to vary around the instability strip, down to limits of 1 mma.
3

Evolução empírica da faixa de instabilidade das estrelas ZZ Ceti

Costa, Alex Fabiano Murillo da January 2007 (has links)
As estrelas ZZ Cetis, também chamadas de DAVs, são anãs brancas com atmosfera de hidrogênio que mostram variabilidade fotométrica. Neste trabalho buscamos estudar a pureza, a existência ou não de variáveis e estrelas constantes com mesmas Tef e log g, e definir com melhor precisão os contornos da faixa de instabilidade das estrelas ZZ Cetis. Para isto realizamos observações de séries temporais fotométricas para identificar novas estrelas do tipo ZZ Ceti, e também obtivemos espectros óticos para determinação dos parâmetros atmosféricos (Tef e log g), utilizando modelos atmosféricos com convecção descrita pela teoria de comprimento de mistura, com ML2/® = 0, 6. Ao longo deste trabalho identificamos 3 novas estrelas do tipo ZZ Ceti, WDJ0000−0046, WDJ2334+0103 e WDJ1650+3010, dentre 67 para as quais não encontramos variabilidade até o nosso limite de detecção, próximo de 2 mma. Além disto estudamos a distribuição de massa através de espectrosóoticos de 170 estrelas, assim como a comparação destes resultados com outros publicados na literatura. Também analisamos a distribuição de massa de outras amostras de espectrosóticos de anãs brancas: 2253 espectros do Sloan Digital Sky Survey e 449 espectros do Two Degree Field. Em todas distribuições estudadas, observamos um aumento na massa das estrelas da faixa de instabilidade e as mais frias, região de temperatura onde aumentam a convecção e o número de partículas neutras. O aumento de massa observado provavelmente não é real, e sim provocado pela forma como são aproximadas as interações de partículas ionizadas com o campo elétrico (efeito Stark) e de partículas neutras (Van der Walls), nos modelos de atmosfera. A razão pela qual não propomos que o aumento de massa seja real é que os mesmos parâmetros atmosféricos, quando determinados pelas cores fotométricas, não apresentam este aumento. Um resultado de nossa análise é que a faixa de instabilidade das estrelas ZZ Cetis, determinada através de espectrosóticos de alta razão sinal/ruído, contém apenas estrelas variáveis em seu interior. Face á descoberta de estrelas variáveis com amplitudes de 1,5 mma, previamente classificadas como não variáveis, será necessário um estudo mais profundo de todas as estrelas classificadas como não observadas como variáveis (NOV) até o momento, reduzindo os limites de detecção para a faixa de 1 mma, para definirmos com precisão as bordas da faixa de instabilidade das ZZ Cetis. / ZZ Ceti are hydrogen atmosphere white dwarf stars that show photometric variability. In this work we study the purity and define with better precision the borders of the instability strip of the ZZ Cetis stars. We obtained times series photometric observations to identify new ZZ Ceti stars, and optical spectra for the determination of the atmospheric (Teff and log g) parameters, using atmospheric models with convection described by mixing length theory with ML2/® = 0.6. We identified 3 new ZZ Ceti stars: WDJ0000−0046, WDJ2334+0103, and WDJ1650+3010, among 67 stars for which we detected no variability up to our detection limit about 2 mma. We analyzed the mass distribution of the 170 stars we observed with S/N ¸ 70 optical spectra. We also studied the mass distribution of other samples of white dwarfs, 2253 spectra of Sloan Digital Sky Survey and 449 spectra of the Two Degree Field. In all studied distributions, we observed an increase in the mass determined for the stars cooler than the instability strip. This apparent increase occurs in a region where there is an increase in the depth of convection and in the number of neutral particles. We propose the increase in mass is not real, but caused by the form the Stark and Van der Walls broadenings are estimated in the atmospheric models. The reason we do not trust the mass increase is that the determination of masses using photometric colors, for the same stars, do not show such increase. One result from our research is that we find no constant stars inside the instability strip when we consider only our high S/N spectra. Considering the recent discovery of variable stars with amplitudes down to 1.5 mma, previously classified as not variables, we deem it necessary to restudy all stars not observed to vary around the instability strip, down to limits of 1 mma.
4

Evolução empírica da faixa de instabilidade das estrelas ZZ Ceti

Costa, Alex Fabiano Murillo da January 2007 (has links)
As estrelas ZZ Cetis, também chamadas de DAVs, são anãs brancas com atmosfera de hidrogênio que mostram variabilidade fotométrica. Neste trabalho buscamos estudar a pureza, a existência ou não de variáveis e estrelas constantes com mesmas Tef e log g, e definir com melhor precisão os contornos da faixa de instabilidade das estrelas ZZ Cetis. Para isto realizamos observações de séries temporais fotométricas para identificar novas estrelas do tipo ZZ Ceti, e também obtivemos espectros óticos para determinação dos parâmetros atmosféricos (Tef e log g), utilizando modelos atmosféricos com convecção descrita pela teoria de comprimento de mistura, com ML2/® = 0, 6. Ao longo deste trabalho identificamos 3 novas estrelas do tipo ZZ Ceti, WDJ0000−0046, WDJ2334+0103 e WDJ1650+3010, dentre 67 para as quais não encontramos variabilidade até o nosso limite de detecção, próximo de 2 mma. Além disto estudamos a distribuição de massa através de espectrosóoticos de 170 estrelas, assim como a comparação destes resultados com outros publicados na literatura. Também analisamos a distribuição de massa de outras amostras de espectrosóticos de anãs brancas: 2253 espectros do Sloan Digital Sky Survey e 449 espectros do Two Degree Field. Em todas distribuições estudadas, observamos um aumento na massa das estrelas da faixa de instabilidade e as mais frias, região de temperatura onde aumentam a convecção e o número de partículas neutras. O aumento de massa observado provavelmente não é real, e sim provocado pela forma como são aproximadas as interações de partículas ionizadas com o campo elétrico (efeito Stark) e de partículas neutras (Van der Walls), nos modelos de atmosfera. A razão pela qual não propomos que o aumento de massa seja real é que os mesmos parâmetros atmosféricos, quando determinados pelas cores fotométricas, não apresentam este aumento. Um resultado de nossa análise é que a faixa de instabilidade das estrelas ZZ Cetis, determinada através de espectrosóticos de alta razão sinal/ruído, contém apenas estrelas variáveis em seu interior. Face á descoberta de estrelas variáveis com amplitudes de 1,5 mma, previamente classificadas como não variáveis, será necessário um estudo mais profundo de todas as estrelas classificadas como não observadas como variáveis (NOV) até o momento, reduzindo os limites de detecção para a faixa de 1 mma, para definirmos com precisão as bordas da faixa de instabilidade das ZZ Cetis. / ZZ Ceti are hydrogen atmosphere white dwarf stars that show photometric variability. In this work we study the purity and define with better precision the borders of the instability strip of the ZZ Cetis stars. We obtained times series photometric observations to identify new ZZ Ceti stars, and optical spectra for the determination of the atmospheric (Teff and log g) parameters, using atmospheric models with convection described by mixing length theory with ML2/® = 0.6. We identified 3 new ZZ Ceti stars: WDJ0000−0046, WDJ2334+0103, and WDJ1650+3010, among 67 stars for which we detected no variability up to our detection limit about 2 mma. We analyzed the mass distribution of the 170 stars we observed with S/N ¸ 70 optical spectra. We also studied the mass distribution of other samples of white dwarfs, 2253 spectra of Sloan Digital Sky Survey and 449 spectra of the Two Degree Field. In all studied distributions, we observed an increase in the mass determined for the stars cooler than the instability strip. This apparent increase occurs in a region where there is an increase in the depth of convection and in the number of neutral particles. We propose the increase in mass is not real, but caused by the form the Stark and Van der Walls broadenings are estimated in the atmospheric models. The reason we do not trust the mass increase is that the determination of masses using photometric colors, for the same stars, do not show such increase. One result from our research is that we find no constant stars inside the instability strip when we consider only our high S/N spectra. Considering the recent discovery of variable stars with amplitudes down to 1.5 mma, previously classified as not variables, we deem it necessary to restudy all stars not observed to vary around the instability strip, down to limits of 1 mma.
5

Astérosismologie de l'étoile naine blanche variable GD 1212

Desgranges, Guy January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
6

ZZ diboson measurements with the ATLAS detector at the LHC and study of the toroidal magnetic field sensors. / Mesure des dibosons ZZ avec le détecteure ATLAS auprès du LHC et Etude des sondes du champ magnetique toroidal

Protopapadaki, Eftychia Sofia 23 September 2014 (has links)
Les particules élémentaires ainsi que leur interactions sont décrites par le Modèle Standard. Malgré son grand succès, il y a encore des questions à répondre. Dans cette thése, le processus du Modèle Standard ZZ, lorsque les deux bosons Z se désintègrent en paires de leptons, a été étudié. Les données utilisées ont été prises par le détecteur ATLAS durant l'année 2012, ce qui correspond à une luminosité intégrée de 20 fb-1. L'énergie dans le centre de masse était de 8 TeV. Tous les éléments de l'analyse sont présentés dans ce document: la sélection du signal et son efficacité, l'estimation du bruit de fond, les systématiques associées à la mesure, ainsi que la méthode statistique employée pour l'extraction de la section efficace. La section efficace du processus ZZ sur couche de masse a été mesurée à 6.98±0.41(stat.)±0.36(syst.)±0.20(lumi) pb. La section efficace pour chaque canal a été aussi mesurée dans une volume cinématique ``restreint'', proche du volume reconstruit. Toutes les mesures obtenues sont en accord avec les prédictions theoriques. L'auto-interaction des bosons neutres est interdite dans le Modèle Standard. Si des couplages à trois bosons sont observés, ceux-ci indiqueront donc la présence d'une nouvelle physique. Des observables sensibles à la présence des couplages anormaux ont été examinées. L'impulsion transverse du boson le plus énergétique s'est avérée une des plus sensibles, et elle a été donc utilisée pour l'extraction des limites à 95% CL sur les couplages anormaux. Toutes les limites obtenues sont compatibles avec le Modèle Standard. La connaissance du champ magnétique toroïdal dans le détecteur ATLAS est essentielle pour l'estimation précise de la masse des particules. Une étude sur les senseurs utilisés pour la construction de la carte de champ du détecteur ATLAS a montré que 97% des senseurs sont fiables. La carte de champ existante a été examinée, et malgré l'observation d'anomalies, celles-ci ne sont pas susceptibles d'affecter la détermination de l'impulsion des muons, ni donc de l'estimation de la masse du boson de Higgs. / Elementary particles and their interactions are described by the Standard Model. Even successful, there are still some unanswered questions which need to be addressed. In this work, the ZZ Standard Model process was studied in the leptonic decay channel. The data used were collected by the ATLAS detector during 2012 and correspond to an integrated luminosity of 20 fb-1. The center of mass energy was 8 TeV. All the analysis elements, such as the signal selection and efficiencies, the background estimation, the measurement uncertainties and the statistical method employed for the cross section extraction, are discussed in this document. The total ZZ on-shell cross section is measured to be 6.98±0.41(stat.)±0.36(syst.)±0.20(lumi) pb. A measurement of the on-shell ``fiducial'' cross section, defined in a volume close to the reconstructed one, was also performed for each decay channel. Both total and fiducial measurements are in agreement, within uncertainties, with the SM predictions. The neutral boson-self interactions are forbidden in the SM. Therefore, if triple gauge boson couplings are observed, they will indirectly point to the existence of new physics. Observables sensitive to the presence of anomalous triple gauge couplings, along with the optimal binning were investigated. The traverse momentum of the most energetic boson was among the most sensitive observables, and it was thus used in order to extract 95% CL limits on the anomalous coupling parameters. All observed limits are found to be compatible with the SM expectations. In the framework of this thesis a performance study was conducted. In order to increase particles mass measurement precision, the accurate knowledge of the toroidal magnetic field inside the detector is essential. The sensors used for the production of the ATLAS toroidal magnetic field map were studied, and it was found that more than 97% of these sensors are reliable. The existing magnetic field map was probed, and even though inaccuracies were observed, they are not expected to impact muon momentum estimation and thus not to bias the Higgs boson mass measurement.
7

Astérosismologie de l'étoile naine blanche variable GD 1212

Desgranges, Guy January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
8

Search for the Higgs Boson in the process H→ZZ→llνν produced via vector-Boson fusion with the ATLAS detector

Edwards, Clive January 2012 (has links)
The search potential of a Standard Model Higgs boson in the Vector Boson Fusion production mechanism with Higgs boson decaying to two leptons and two neutrinos via decay to two Z bosons with the ATLAS detector is investigated. The ATLAS detector is a general purpose detector in operation at CERN measuring proton-proton collisions produced by the Large Hadron Collider. This channel has been shown to have high sensitivity at large Higgs mass, where large amounts of missing energy in the signal provide good discrimination over expected backgrounds. This work takes a first look at whether the sensitivity of this channel may be improved using the remnants of the vector boson fusion process to pro- vide extra discrimination, particularly at lower mass where sensitivity of the main analysis is reduced because of lower missing energy. Simulated data samples at centre of mass energy 7 Te V are used to derive signal significances over the mass range between 200-600 Ge V / c2. Because of varying signal properties with mass, a low and a high mass event selection were developed and optimized. A comparison between simulated and real data (collected in 2010) is made of variables used in the analysis and the effect of pileup levels corresponding to those in the 2010 data is investigated. Possible methods to estimate some of the main backgrounds to this search are described and discussed. The impact • of important theoretical and detector related systematics are taken into account. Final results are presented in the form of 95 % Confidence Level exclusion limits on the signal cross section relative to the SM prediction as a function of Higgs boson mass, based on an integrated luminosity of 33.4 pb -1 of data collected during 2010.
9

Étude de la bande d'instabilité des étoiles naines blanches variables de type ZZ Ceti

Gianninas, Alexandros January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
10

Search for a heavy scalar boson in the ZZ->2l2v channel with the CMS experiment at the LHC using 2016 data at 13 TeV

Delannoy, Hugo 05 April 2019 (has links) (PDF)
Les premières années d’opération du LHC à 7 et 8 TeV ont permis de tester de nombreux aspects du modèle standard (MS) de la physique des particules avec comme point d’orgue la découverte d’un boson scalaire compatible avec celui du MS. Cependant, malgré son succès, le MS n’explique pas tout. De nombreux modèles essayent donc de combler les manques du MS et certains requièrent un secteur scalaire étendu. Cette thèse étudie ce secteur scalaire et présente en particulier la recherche d’un nouveau boson scalaire massif en utilisant les 35,9 fb-1 de données récoltées au LHC à 13 TeV en 2016. Cette recherche se concentre sur le processus H→ZZ→2l2ν où l est un electron ou un muon, et ν un neutrino. Une analyse statistique des distributions de masse transverse du boson (Z→l^+ l^-) reconstruit et de l’énergie transverse manquante est réalisée en catégories de jets et de saveurs de lepton après une sélection des événements dans le but de faire sortir un signal potentiel par rapport aux bruits de fond. Divers scenarios de masse, largeur et de mode de productions sont testés pour un boson scalaire H et aucun excès significatif n’est observé dans les données pour une gamme de masses allant de 300 GeV à 3 TeV. Des limites supérieures à 95% de niveau de confiance sur la section efficace σ(pp→H→ZZ) sont établies. Ces résultats sont combinés avec deux autres canaux étudiés par la collaboration CMS :H→ZZ→4l et H→ZZ→2l2q, où q représente un quark. Cette combinaison est publiée (CMS Collaboration, « Search for a new scalar resonance decaying to a pair of Zbosons in proton-proton collisions at √s=13 TeV », JHEP, vol. 06, pp. 127,2018) et aucun excès significatif n’est observé dans les données pour des masses entre 130 GeV et 3 TeV. Un bruit de fond majeur pour cette analyse est le bruit de fond instrumental Z+jets. Son estimation est faite non pas par simulation mais en utilisant les données récoltées par CMS. Un chapitre entier est dédié à l’étude de ce bruit de fond et les incertitudes sur celui-ci sont estimées en détails pour la première fois. En particulier les sources d’incertitudes sont divisées en celles d’origine statistique, systématique et celles inhérentes à la méthode d’estimation de ce bruit de fond. Elles sont respectivement de l’ordre de 50%, 50% et 10%. / The first years of operation of the LHC at 7 and 8TeV (run 1) allowed to probemany aspects of the Standard Model (SM) of particle physics, confirming many predictions up to a high level of precision. An awaited event was the discovery of a scalar boson compatible with the SM in 2012. However, despite its success, the SM cannot explain everything on its own. Models going beyond the SM try to address such issues, and in particular classes of BSM theories require an extended scalar sector.The scope of this thesis falls within the direct search for heavy BSM scalar boson(H) using 35,9 fb-1 of data taken at LHC at 13TeV during 2016 operations. Inparticular, the thesis focuses on H→ZZ→2l2ν where l is an electron or a muon, and ν a neutrino.A statistical analysis of the transversemass distributions of the reconstructed Z boson and the missing transverse energy isperformed in categories of jet and lepton flavour after selecting events in order to enhancethe number of potential signal events in comparison to background events. Variousscenarii of masses, widths and production mechanisms (gluon fusion and vector boson fusion) are tested and no excess is observed in data compared to backgroundestimations for a scalar mass between 300 GeV and 3TeV. Upper exclusion limits onthe cross section of a potential signal are set using the CLs method.The results of this analysis are combined with two other channels studied by theCMS collaboration: H→ZZ→4l and H→ZZ→2l2q, where q is a quark.This combinationhas been published (CMS Collaboration, « Search for a new scalar resonance decaying to a pair of Zbosons in proton-proton collisions at √s=13 TeV », JHEP, vol. 06, pp. 127,2018) and no significanthint for BSM physics is observed for a scalar mass between 130 GeV and 3TeV.A critical background to control for this analysis is the Z+jet background. Its estimation is done using a data-driven method.A full chapter is dedicated to the study of this background. The present thesis is the first time that the uncertainties on the data-driven estimationof the Z+jet background are estimated in detail. Uncertainties are dividedinto statistical uncertainties, systematic uncertainties and uncertainties inherent to themethod, the latter being computed from a closure test of the method and evaluated to10%. The relative statistical and systematic uncertainties are both of the order of 50%. / Option Physique du Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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