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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.
561

Fabrication et caractérisation de détecteurs à gouttelettes en surchauffe à bas bruit de fond au sein du projet PICASSO

Piro, Marie-Cécile January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
562

Analyse cinématique de l'hydrogène ionisé et étude du gaz ionisé diffus de trois galaxies du Groupe Sculpteur : NGC253, NGC300 et NGC247

Hlavacek-Larrondo, Julie January 2009 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
563

Étude de la cinématique HI (21cm) et H-Alpha de la galaxie du Triangle (M33)

Kam, Sié Zacharie 05 1900 (has links)
No description available.
564

Flavor and Dark Matter Issues in Supersymmetric Models

Chowdhury, Debtosh January 2013 (has links) (PDF)
The Standard Model of particle physics attempts to unify the fundamental forces in the Universe (except gravity). Over the years it has been tested in numerous experiments. While these experimental results strengthen our understanding of the SM, they also point out directions for physics beyond the SM. In this thesis we assume supersymmetry (SUSY) to be the new physics beyond the SM. We have tried to analyze the present status of low energy SUSY after the recent results from direct (collider) and indirect (flavor, dark matter) searches .We have tried to see the complementarity between these apparently different experimental results and search strategies from the context of low energy SUSY. We show that such complementarity does exist in well-defined models of SUSY breaking like mSUGRA, NUHM etc. The first chapter outlines the present status of the SM and discusses about the unanswered questions in SM. Keeping SUSY as the new physics beyond the SM, we also detail about its present experimental status. Chapter1 ends with the motivation and comprehensive description about each chapter of the thesis. In chapter2, we present an introduction to formal structure of SUSY algebra and the structure of MSSM. One of the such complementarities we have studied is between flavor and dark matter. In general flavor violation effects are not considered when studying DM regions in minimal SUSY models like mSUGRA. If however flavor violation does get generated through non-minimal SUSY breaking sector, one of the most susceptible regions would be the co-annihilation region for neutralino DM. In chapter 3 we consider flavor violation in the sleptonic sector and study its implications on the stau co-annihilation region. In this work we have taken flavor violation between the right-handed smuon (˜µR) and stau (˜τR). Due to this flavor mixing the lightest slepton (ĺ1) is a flavor mixed state. We have studied the effect of such ĺ11’s in the ‘stau co-annihilation’ region of the parameter space, where the relic density of the neutralinos gets depleted due to efficient co-annihilation with the staus. Limits on the flavor violating insertion in the right-handed sleptonic sector mainly comes from BR(τ → µγ). These limits are weak in some regions of the Parameter space where cancellations happen with in the amplitudes. We look for overlaps in parameter space where both the co-annihilation condition as well as the cancellations with in the amplitudes occur. We have shown that in models with non-universal Higgs boundary conditions (NUHM) overlap between these two regions is possible. The effect of flavor violation is two fold: (a) It shifts the co-annihilation regions towards lighter neutralino masses and (b) the co-annihilation cross sections would be modified with the inclusion of flavor violating diagrams which can contribute significantly. In the overlap regions, the flavor violating cross sections become comparable and in some cases even dominant to the flavor conserving ones. A comparison among the different flavor conserving and flavor violating channels, which contribute to the neutralino annihilation cross-section, is presented. One of the challenges of addressing quantitatively the complementarity problems is the lack of proper spectrum generator (numerical tools which computes SUSY sparticle spectrum in the presence of flavor violation in the sfermionic sector). For the lack of a publicly available code which considers general flavor violating terms in the renormalization group equations (RGE) we have developed a SUSY spectrum calculator, named as SuSeFLAV .It is a code written in FORTRAN language and calculates SUSY particle spectrum (with in the context of gravity mediation) in type I seesaw, in the presence of heavy right handed neutrinos (RHN). SuSeFLAV also calculates the SUSY spectrum in other type of SUSY breaking mechanisms (e.g. gauge mediation). The renormalization group (RG) flow of soft-SUSY breaking terms will generate large off-diagonal terms in the slepton sector in the presence of this RHNs, which will give rise to sizable amount of flavor violating (LFV) decays at the weak scale. Hence, in this code we also calculate the different rare LFV decays like, µ → eγ, τ → µγ etc. In SuSeFLAV the user has the freedom to choose the scale of the RHNs as well as the mixing matrix in neutrino sector. It is also possible to choose the values of the SUSY breaking input parameters at the user defined scale. The details of this package is discussed in chapter 4. Many of the present studies of complementarity between the direct and indirect searches are inadequate to address realistic scenarios, where SUSY breaking could be much more general compared to the minimal models. The work in this thesis is a step to wards this direction. Having said that, in the present thesis we have considered modifications of popular models with either explicit flavor violating terms (in some sectors) or sources of flavor violation through new particles and new couplings motivated by strong phenomenological reasons like neutrino masses. It should be noted however, the numerical tool which has been developed during the thesis can be used to address more complicated problems like with complete flavor violation in models of SUSY breaking. One of the popular mechanisms of neutrino mass generation is the so called Seesaw Mechanism. Depending on the extra matter sector present in the theory there are three basic types of them. The type I seesaw, which has singlet bright-handed neutrinos, the type II seesaw contains scalar triplets and type III seesaw has additional fermionic triplets. One of the implications of the seesaw mechanism is flavor violation in the sfermionic sector even in the presence of flavor universal SUSY breaking. This leads to a complementarity between flavor experiments and direct SUSY searches at LHC. With the announcement of the results from the reactor neutrino oscillation experiments, the reactor mixing angle (θ13) in the neutrino mixing matrix (PMNS matrix) gets fixed to a rather large non-zero value. In SO (10) GUT theories neutrino Yukawa couplings of type I seesaw gets related to the up-type fermion sector of the SM. In chapter 5 we update the status of SUSY type I seesaw assuming SO (10)- like relations for neutrino Dirac Yukawa couplings and two cases of mixing, one large, PMNS-like, and another small, CKM-like, are considered. It is shown that for the large mixing case, only a small range of parameter space with moderate tan β is still allowed. It is shown that the renormalization group induced flavor violating slepton mass terms are highly sensitive to the Higgs boundary conditions. Depending on the choice of the parameters, they can either lead to strong enhancements or cancellations with in the flavor violating terms. We have shown that in NUHM scenario there could be possible cancellations which relaxes the severe constraints imposed by lepton flavor violation compared to mSUGRA. We further updated the flavor consequences for the type II seesaw in SUSY theories. As mentioned previously in type II seesaw neutrino mass gets generated due to exchange of heavy SU (2) L triplet Higgs field. The ratio of lepton flavor violating branching ratios (e.g. BR(τ → µγ) /BR (µ → eγ) etc.) are functions of low energy neutrino masses ans mixing angles. In chapter 6 we have analyzed how much these ratios become, after the experimental measurement of θ13, in the whole SUSY parameter space or in other words how much these ratios help to constrain the SUSY parameter space. We compute different factors which can affect this ratios. We have shown that the cMSSM-like scenarios, in which slepton masses are taken to be universal at the high scale, predict 3.5 BR(τ → µγ) / BR(µ → eγ) 30 for normal hierarchical neutrino masses. We Show that the current MEG limit puts severe constraints on the light sparticle spectrum in cMSSM-like model for seesaw scale with in1013 - 1015 GeV. These constraints can be relaxed and relatively light sparticle spectrum can be still allowed by MEG result in a class of models in which the soft mass of triplet scalar is taken to be non-universal at the GUT scale. In chapter 7 we have analyzed the effect of largen eutrino Yukawa couplings on the supersymmetric lightest Higgs mass. In July 2012, ATLAS and CMS collaboration have updated the Higgs search in LHC and found an evidence of a scalar particle having mass around 125 GeV. The one-loop contribution to Higgs mass mainly depends on the top trilinear couplings (At), the SUSY scale and the top Yukawa (Yt). Thus in models with extra large Yukawa couplings at the high scale like the seesaw mechanism ,the renormalization scaling of the At parameter can get significantly affected. This in turn can modify the light Higgs mass at the weak scale for the same set of SUSY parameters. We have shown in type I seesaw with (Yν ~ 3Yu) the light Higgs mass gets reduced by 2 - 3 GeV in most of the parameter rspace. In other words the SUSY scale must be pushed high enough to achieve similar Higgs mass compared to the cMSSM scenario. We have got similar effect in SUSY type III seesaw scenario with (Yν ~Yu) at the GUT scale. In chapter 8 we summarize the results of the thesis and discuss the possible future directions.
565

From Spitzer Mid-InfraRed Observations and Measurements of Peculiar Velocities to Constrained Simulations of the Local Universe / Des observations mi-InfraRouges du Télescope Spitzer et des mesures de vitesses particulières aux simulations contraintes de l'univers local

Sorce, Jenny 12 June 2014 (has links)
Les galaxies sont des sondes observationnelles pour l'étude des structures de l'Univers. Leur mouvement gravitationnel permet de tracer la densité totale de matière. Par ailleurs, l'étude de la formation des structures et galaxies s'appuie sur les simulations numériques cosmologiques. Cependant, un seul univers observable à partir d'une position donnée, en temps et espace, est disponible pour comparaison avec les simulations. La variance cosmique associée affecte notre capacité à interpréter les résultats. Les simulations contraintes par les données observationnelles constituent une solution optimale au problème. Réaliser de telles simulations requiert les projets Cosmicflows et CLUES. Cosmicflows construits des catalogues de mesures de distances précises afin d'obtenir les déviations de l'expansion. Ces mesures sont principalement obtenues avec la corrélation entre la luminosité des galaxies et la vitesse de rotation de leur gaz. La calibration de cette relation est présentée dans le mi-infrarouge avec les observations du télescope spatial Spitzer. Les estimations de distances résultantes seront intégrées au troisième catalogue de données du projet. En attendant, deux catalogues de mesures atteignant 30 et 150 h−1 Mpc ont été publiés. Les améliorations et applications de la méthode du projet CLUES sur les deux catalogues sont présentées. La technique est basée sur l'algorithme de réalisation contrainte. L'approximation de Zel'dovich permet de calculer le champ de déplacement cosmique. Son inversion repositionne les contraintes tridimensionnelles reconstruites à l'emplacement de leur précurseur dans le champ initial. La taille inégalée, 8000 galaxies jusqu'`a une distance de 150 h−1 Mpc, du second catalogue a mis en évidence l'importance de minimiser les biais observationnels. En réalisant des tests sur des catalogues de similis, issus des simulations cosmologiques, une méthode de minimisation des biais peut être dérivée. Finalement, pour la première fois, des simulations cosmologiques sont contraintes uniquement par des vitesses particulières de galaxies. Le procédé est une réussite car les simulations obtenues ressemblent à l'Univers Local. Les principaux attracteurs et vides sont simulés à des positions approchant de quelques mégaparsecs les positions observationnelles, atteignant ainsi la limite fixée par la théorie linéaire / Galaxies are observational probes to study the Large Scale Structure. Their gravitational motions are tracers of the total matter density and therefore of the Large Scale Structure. Besides, studies of structure formation and galaxy evolution rely on numerical cosmological simulations. Still, only one universe observable from a given position, in time and space, is available for comparisons with simulations. The related cosmic variance affects our ability to interpret the results. Simulations constrained by observational data are a perfect remedy to this problem. Achieving such simulations requires the projects Cosmicflows and CLUES. Cosmicflows builds catalogs of accurate distance measurements to map deviations from the expansion. These measures are mainly obtained with the galaxy luminosity-rotation rate correlation. We present the calibration of that relation in the mid-infrared with observational data from Spitzer Space Telescope. Resulting accurate distance estimates will be included in the third catalog of the project. In the meantime, two catalogs up to 30 and 150 h−1 Mpc have been released. We report improvements and applications of the CLUES’ method on these two catalogs. The technique is based on the constrained realization algorithm. The cosmic displacement field is computed with the Zel’dovich approximation. This latter is then reversed to relocate reconstructed three-dimensional constraints to their precursors’ positions in the initial field. The size of the second catalog (8000 galaxies within 150 h−1 Mpc) highlighted the importance of minimizing the observational biases. By carrying out tests on mock catalogs, built from cosmological simulations, a method to minimize observational bias can be derived. Finally, for the first time, cosmological simulations are constrained solely by peculiar velocities. The process is successful as resulting simulations resemble the Local Universe. The major attractors and voids are simulated at positions approaching observational positions by a few megaparsecs, thus reaching the limit imposed by the linear theory / Die Verteilung der Galaxien liefert wertvolle Erkenntnisse über die großräumigen Strukturen im Universum. Ihre durch Gravitation verursachte Bewegung ist ein direkter Tracer für die Dichteverteilung der gesamten Materie. Die Strukturentstehung und die Entwicklung von Galaxien wird mithilfe von numerischen Simulationen untersucht. Es gibt jedoch nur ein einziges beobachtbares Universum, welches mit der Theorie und den Ergebnissen unterschiedlicher Simulationen verglichen werden muß. Die kosmische Varianz erschwert es, das lokale Universum mit Simulationen zu reproduzieren. Simulationen, deren Anfangsbedingungen durch Beobachtungsdaten eingegrenzt sind (“Constrained Simulations”) stellen eine geeignete Lösung dieses Problems dar. Die Durchführung solcher Simulationen ist das Ziel der Projekte Cosmicflows und CLUES. Im Cosmicflows-Projekt werden genaue Entfernungsmessungen von Galaxien erstellt, welche die Abweichung von der allgemeinen Hubble- Expansion abbilden. Diese Messungen werden hauptsächlich aus der Korrelation zwischen Leuchtkraft und Rotationsgeschwindigkeit von Spiralgalaxien gewonnen. In dieser Arbeit wird die Kalibrierung dieser Beziehung im mittleren Infrarot mithilfe von Daten vom Spitzer Space Telescope vorgestellt. Diese neuen Entfernungsbestimmungen werden im dritten Katalog des Cosmicflows Projekts enthalten sein. Bisher wurden zwei Kataloge veröffentlicht, mit Entfernungen bis zu 30 beziehungsweise 150 h−1 Mpc. In dieser Arbeit wird die CLUESMethode auf diese zwei Kataloge angewendet und Verbesserungen warden vorgestellt und diskutiert. Zunächst wird das kosmische Verschiebungsfeld mithilfe der Zeldovich-Näherung bestimmt. In umgekehrter Richtung kann man damit die aus heutigen Beobachtungsdaten rekonstruierten dreidimensionalen Constraints an ihren Ursprungsort im frühen Universum zurückzuversetzen. Durch den großen Datenumfang des cosmicflows-2 Katalogs (8000 Galaxien bis zu einer Entfernung von 150 h−1 Mpc) ist es besonders wichtig, den Einfluss verschiedener Beobachtungsfehler zu minimieren. Eine für das lokale Universum angepasste Korrekturmethode lässt sich durch die Untersuchung von Mock-Katalogen finden, welche aus kosmologischen Simulationen gewonnen werden. Schließlich stellt diese Arbeit erstmals kosmologische Simulationen vor, die ausschließlich durch Pekuliargeschwindigkeiten eingegrenzt sind. Der Erfolg dieser Methode wird dadurch bestätigt, dass die dadurch erzeugten Simulationen dem beobachteten lokalen Universum sehr ähnlich sind. Die relevanten Attraktoren und Voids liegen in den Simulationen an Positionen, welche bis auf wenige Megaparsec mit den beobachteten Positionen übereinstimmen. Die Simulationen erreichen damit die durch die lineare Theorie gegebene Genauigkeitsgrenze
566

The fall and rise of antimatter: probing leptogenesis and dark matter models

Vertongen, Gilles 25 September 2009 (has links)
Big Bang Nucleosynthesis (BBN), together with the analyses of the Cosmic Microwave Background (CMB) anisotropies, confirm what our day to day experience of life attests :antimatter is far less present than matter in the Universe. In addition, these observables also permit to evaluate that there exists about one proton for every 10^{10} photons present in the Universe. This is in contradiction with expectations coming from the standard hot big bang, where no distinction between matter and antimatter is made, and where subsequent annihilations would lead to equal matter and antimatter contents, at a level 10^{−10} smaller than the observed one. The Standard Model of fundamental interactions fails to explain this result, leading us to search for ‘Beyond the Standard Model’ physics.<p><p>Among the possible mechanism which could be responsible for the creation of such a matter asymmetry, leptogenesis is particularly attractive because it only relies on the same ingredients previously introduced to generate neutrino masses. Unfortunatelly, this elegant proposal suffers from a major difficulty :it resists to any tentative of being probed by our low energy observables. In this thesis, we tackle the problem the other way around and propose a way to falsify this mechanism. Considering the type-I leptogenesis mechanism, i.e. a mechanism based on the asymmetric decay of right-handed neutrinos, in a left-right symmetric framework, we show that the observation of a right-handed gauge boson W_R at future colliders would rule out any possibility for such mechanism to be responsible of the matter asymmetry present in our Universe.<p><p>Another intriguing question that analyses of the anisotropies of the CMB confirmed is the presence of a non-baryonic component of matter in our Universe, i.e. the dark matter. As hinted by observations of galactic rotation curves, it should copiously be present in our galactic halo, but is notoriously difficult to detect directly. We can take advantage on the fact that antimatter almost disappeared from our surroundings to detect the contamination of cosmic rays from standard sources the annihilation products of dark matter would produce.<p><p>The second subject tackled in this work is the study of the imprints the Inert Doublet Modem (IDM) could leave in (charged) cosmic rays, namely positrons, antprotons and antideuterons. This model, first proposed to allow the Bout-Englert-Higgs particle to evade the Electroweak Precision Test (EWPT) measurements, introduces an additional scalar doublet which is inert in the sense that it does not couple directly to fermions. This latter property brings an additional virtue to this additional doublet :since it interacts weakly with particles, it can play the role of dark matter. This study will be done in the light of the data recently released by the PAMELA, ATIC and Fermi-GLAST collaborations, which reported e^± excesses in two different energy ranges. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
567

Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton events with the ATLAS detector at the LHC

Chiu, Justin 22 December 2020 (has links)
This thesis presents the search for the dark sector process h -> Zd Zd -> 4l in events collected by the ATLAS detector at the Large Hadron Collider in 2015--2018. In this theorized process, the Standard Model Higgs boson (h) decays to four leptons via two intermediate Beyond-the-Standard-Model particles each called Zd. This process arises from interactions of the Standard Model with a dark sector. A dark sector consists of one or more new particles that have limited or zero interaction with the Standard Model, such as the new vector boson Zd (dark photon). It could have a rich and interesting phenomenology like the visible sector (the Standard Model) and could naturally address many outstanding problems in particle physics. For example, it could contain a particle candidate for dark matter. In particular, Higgs decays to Beyond-the-Standard-Model particles are well-motivated theoretically and are not tightly constrained; current measurements of Standard Model Higgs properties permit the fraction of such decays to be as high as approximately 30%. The results of this search do not show evidence for the existence of the h -> Zd Zd -> 4l process and are therefore interpreted in terms of upper limits on the branching ratio B(h -> Zd Zd) and the effective Higgs mixing parameter kappa^prime. / Graduate
568

Production de plasmons et degré d’ionisation pour des reculs nucléaires dans les détecteurs de matière sombre au silicium de SuperCDMS

Michaud, Émile 08 1900 (has links)
SuperCDMS (Super Cryogenic Dark Matter Search) est une expérience de détection directe de la matière sombre qui utilise des détecteurs cryogéniques au silicium et au germanium capables de mesurer des dépôts d'énergie aussi petits que quelques eV. L'un des défis les plus importants de la recherche de la matière sombre est de réussir à bloquer les nombreux bruits de fond. Une de ces sources de bruit de fond est la production de plasmons par la diffusion Compton, un phénomène ne déposant généralement qu'une dizaine d’eV et affectant surtout les détecteurs à semi-conducteurs. Dans cet ouvrage, nous allons estimer le taux de production de ces plasmons et démontrer qu'il est primordial de tenir compte de ce bruit de fond avant de pouvoir affirmer avoir trouvé la matière sombre. Un autre enjeu majeur de SuperCDMS est l'étalonnage de ses détecteurs à très faible énergie. En effet, la matière sombre est supposée interagir avec le noyau des atomes. Toutefois, il n'existe présentement aucune donnée sur le degré d'ionisation pour des reculs nucléaires de moins de 0,7 keVnr dans le silicium, où keVnr représente l'énergie déposée en keV lors d'une collision nucléaire (nr). Dans la deuxième partie de cet ouvrage, nous allons montrer comment l'expérience IMPACT (Ionization Yield Measurement with Phonons At Cryogenic Temperature), une sous-expérience de SuperCDMS composée de membres de SuperCDMS, compte mesurer ce degré d'ionisation pour des reculs nucléaires entre 0,1 et 4 keVnr dans le silicium. Connaître ce degré d'ionisation est d'une grande importance pour SuperCDMS car il permet de reconstruire l'énergie déposée par une particule de matière sombre lorsqu'elle effectue une collision nucléaire dans ses détecteurs de matière sombre. / SuperCDMS (Super Cryogenic Dark Matter Search) is an experiment for the direct detection of dark matter that uses cryogenic silicon and germanium detectors which can measure energy deposition as low as a few eV. One of the biggest challenges in the search for dark matter is to block the various background events. One of those background source is the excitation of plasmons by Compton scattering, a phenomenon that generally deposits about ten eV and which affects mainly semiconductor detectors. In this work, we will estimate the production rate of plasmons and argue that we must understand this background in order to claim evidence of dark matter. One of SuperCDMS's other challenges is the calibration of its detectors at very low energy. Indeed, dark matter is known to interact with the atom's nucleus, but unfortunately, there is no data at the moment about the ionization yield of nuclear recoils below 0,7 keVnr in silicon, where keVnr is the energy deposited in keV in a nuclear recoil (nr). In the second part of this work, we will show how the IMPACT experiment (Ionization yield Measurement with Phonons At Cryogenic Temperature), a sub-experiment of SuperCDMS composed of members of SuperCDMS, aims to measure the ionization yield for nuclear recoils between 0,1 and 4 keVnr in silicon. It is important for SuperCDMS to know this ionization yield to reconstruct the energy deposited in their detectors by a nuclear recoil from a dark matter particle.
569

Mesures d'étalonnage aux neutrons et caractérisation par étude Monte Carlo de la réponse des détecteurs à gouttelettes surchauffées conçus pour la recherche et la détection directe du neutralino (la matière sombre) menant aux résultats finaux de l'expérience PICASSO

Lafrenière, Matthieu 12 1900 (has links)
No description available.
570

Dark Matter Indirect Detection with charged cosmic rays / Parcellisation de la surface corticale basée sur la connectivité : vers une exploration multimodale

Giesen, Gaelle 25 September 2015 (has links)
Les preuves pour l'existence de la matière noire (MN), sous forme d'une particule inconnue qui rempli les halos galactiques, sont issues d'observations astrophysiques et cosmologiques: son effet gravitationnel est visible dans les rotations des galaxies, des amas de galaxies et dans la formation des grandes structures de l'univers. Une manifestation non-gravitationnelle de sa présence n'a pas encore été découverte. L'une des techniques les plus prometteuse est la détection indirecte de la MN, consistant à identifier des excès dans les flux de rayons cosmiques pouvant provenir de l'annihilation ou la désintégration de la MN dans le halo de la Voie Lactée. Les efforts expérimentaux actuels se focalisent principalement sur une gamme d'énergie de l'ordre du GeV au TeV, où un signal de WIMP (Weakly Interacting Massive Particles) est attendu. L'analyse des mesures récentes et inédites des rayons cosmiques chargés (antiprotons, électrons et positrons) et leurs émissions secondaires et les améliorations des modèles astrophysiques sont présentées.Les données de PAMELA sur les antiprotons contraignent l'annihilation et la désintégration de la MN de manière similaire (et même légèrement meilleurs) que les contraintes les plus fortes venant des rayons gamma, même dans le cas où les énergies cinétiques inférieures à 10 GeV sont écartées. En choisissant des paramètres astrophysiques différents (modèles de propagation et profils de MN), les contraintes peuvent changer d'un à deux ordres de grandeur. Pour exploiter la totalité de la capacité des antiprotons à contraindre la MN, des effets précédemment négligés sont incorporés et se révèlent être importants dans l'analyse des données inédites de AMS-02 : ajouter les pertes d'énergie, la diffusion dans l'espace des moments et la modulation solaire peut modifier les contraintes, même à de hautes masses. Une mauvaise interprétation des données peut survenir si ces effets ne sont pas pris en compte. Avec les flux de protons et d'hélium exposé par AMS-02, le fond astrophysique et ces incertitudes du ratio antiprotons sur protons sont réévalués et comparés aux données inédites de AMS-02. Aucune indication pour un excès n'est trouvé. Une préférence pour un halo confinant plus large et une dépendance en énergie du coefficient de diffusion plus plate apparaissent. De nouvelles contraintes sur l'annihilation et la désintégration de la MN sont ainsi dérivés.Les émissions secondaires des électrons et des positrons peuvent aussi contraindre l'annihilation et la désintégration de la MN dans le halo galactique : le signal radio dû à la radiation synchrotron des électrons et positrons dans le champs magnétique galactique, les rayons gamma des processus de bremsstrahlung avec le gas galactique et de Compton Inverse avec le champs radiatif interstellaire sont considérés. Différentes configurations de champs magnétique galactique et de modèles de propagation et des cartes de gas et de champs radiatif interstellaire améliorés sont utilisées pour obtenir des outils permettant le calculs des émissions synchrotrons et bremsstrahlung venant de MN de type WIMP. Tous les résultats numériques sont incorporés dans la dernière version du Poor Particle Physicist Coookbook for DM Indirect Detection (PPPC4DMID).Une interprétation d'un possible excès dans les données de rayons gamma de Fermi-LAT au centre galactique comme étant dû à l'annihilation de MN en canaux hadronique et leptonique est analysée. Dans une approche de messagers multiples, le calcul des émissions secondaires est amélioré et se révèle être important pour la détermination du spectre pour le canal leptonique. Ensuite, les limites provenant des antiprotons sur l'annihilation en canal hadronique contraignent sévèrement l'interprétation de cet excès comme étant dû à la MN, dans le cas de paramètres de propagation et de modulation solaire standards. Avec un choix plus conservatif de ces paramètres elles s'assouplissent considérablement. / Overwhelming evidence for the existence of Dark Matter (DM), in the form of an unknownparticle filling the galactic halos, originates from many observations in astrophysics and cosmology: its gravitational effects are apparent on galactic rotations, in galaxy clusters and in shaping the large scale structure of the Universe. On the other hand, a non-gravitational manifestation of its presence is yet to be unveiled. One of the most promising techniques is the one of indirect detection, aimed at identifying excesses in cosmic ray fluxes which could possibly be produced by DM annihilations or decays in the Milky Way halo. The current experimental efforts mainly focus in the GeV to TeV energy range, which is also where signals from WIMPs (Weakly Interacting Massive Particles) are expected. Focussing on charged cosmic rays, in particular antiprotons, electrons and positrons, as well as their secondary emissions, an analysis of current and forseen cosmic ray measurements and improvements on astrophysical models are presented. Antiproton data from PAMELA imposes contraints on annihilating and decaying DM which are similar to (or even slightly stronger than) the most stringent bounds from gamma ray experiments, even when kinetic energies below 10 GeV are discarded. However, choosing different sets of astrophysical parameters, in the form of propagation models and halo profiles, allows the contraints to span over one or two orders of magnitude. In order to exploit fully the power of antiprotons to constrain or discover DM, effects which were previously perceived as subleading turn out to be relevant especially for the analysis of the newly released AMS-02 data. In fact, including energy losses, diffusive reaccelleration and solar modulation can somewhat modify the current bounds, even at large DM masses. A wrong interpretation of the data may arise if they are not taken into account. Finally, using the updated proton and helium fluxes just released by the AMS-02 experiment, the astrophysical antiproton to proton ratio and its uncertainties are reevaluated and compared to the preliminarly reported AMS-02 measurements. No unambiguous evidence for a significant excess with respect to expectations is found. Yet, some preference for thicker halos and a flatter energy dependence of the diffusion coefficient starts to emerge. New stringed constraints on DM annihilation and decay are derived. Secondary emissions from electrons and positrons can also be used to constrain DM annihilation or decay in the galactic halo. The radio signal due to synchrotron radiation of electrons and positrons on the galactic magnetic field, gamma rays from bremsstrahlung processes on the galactic gas densities and from Inverse Compton scattering processes on the interstellar radiation field are considered. With several magnetic field configurations, propagation scenarios and improved gas density maps and interstellar radiation field, state-of-art tools allowing the computaion of synchrotron and bremssttrahlung radiation for any WIMP DM model are provided. All numerical results for DM are incorporated in the release of the Poor Particle Physicist Coookbook for DM Indirect Detection (PPPC4DMID). Finally, the possible GeV gamma-ray excess identified in the Fermi-LAT data from the Galactic Center in terms of DM annihilation, either in hadronic or leptonic channels is studied. In order to test this tantalizing interprestation, a multi-messenger approach is used: first, the computation of secondary emisison from DM with respect to previous works confirms it to be relevant for determining the DM spectrum in leptonic channels. Second, limits from antiprotons severely constrain the DM interpretation of the excess in the hadronic channel, for standard assumptions on the Galactic propagation parameters and solar modulation. However, they considerably relax if more conservative choices are adopted.

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