The prompt production of &chi / c quarkonia is studied in proton-proton collisions at 7 TeV, using data collected by CMS in 2011 corresponding to an integrated luminosity of 4.6 fb &minus / 1. The &chi / c mesons are reconstructed through their radiative decays to J/&psi / and photon with J/&psi / &rarr / &mu / +&mu / &minus / . The photons are reconstructed through their conversion in electron-positron pairs in the tracking detector which gives a mass resolution sufficient for resolving these states. The ratio of the prompt production cross sections for the &chi / c1 and &chi / c2 states, &sigma / (&chi / c2)/&sigma / (&chi / c1), has been determined as a function of the J/&psi / transverse momentum between 7 and 25 GeV/c.

Scherk-Schwarz reductions are a generalization of Kaluza-Klein reductions in which the higher dimensional fields are allowed to have a dependence on the compactiifed coordinates. This is possible only if the higher dimensional theory has a global symmetry and the dependence is dictated by this symmetry. In this thesis we consider generalised Scherk Schwarz reductions of supergravity and superstring theories with twists by electromagnetic dualities that are symmetries of the equations of motion but not of the action, such as the S-duality of $D=4, N=4$ super-Yang-Mills coupled to supergravity. The reduction cannot be done on the action itself, but must be done either on the field equations or on a duality invariant form of the action, such as one in the doubled formalism in which potentials are introduced for both electric and magnetic fields. The resulting theory in odd dimensions has massive form fields satisfying a self-duality condition $dA sim m*A$. We apply these methods to theories in $D=4,6,8$, and obtain new gauged supergravity theories with massive form fields, with Chern-Simons like couplings and with a scalar potential in $D=3,5,7$.

Les domaines scientifiques, nécessitant l'imagerie d'objets de petites dimensions (micrométriques voire nanométriques) et peu émissifs, sont de plus en plus nombreux (physique des plasmas, astrophysique, physique des matériaux, biotechnologies,...) et les challenges posés par l'étude de ces objets en font un axe de recherche et de développement en constante évolution. Le travail présenté dans ce document a un objectif double : présenter les spécificités de l'instrumentation associée à ce domaine de recherche ainsi que les facteurs susceptibles d'améliorer la précision des systèmes d'imagerie ; présenter les techniques numériques d'analyse de données et de reconstruction capables de restituer des résolutions spatiales en adéquation avec les dimensions de l'objet étudié. La similitude des algorithmes d'analyse de données et de reconstruction appliqués à la fusion par confinement inertielle et à l'imagerie moléculaire de fluorescence, deux domaines scientifiques dont les enjeux sont très différents, montre combien l'imagerie d'objets de petites dimensions est un domaine de recherche à la frontière d'un grand nombre de disciplines scientifiques

De nombreux domaines, tels que le biomédical, la micro-fluidique ou l'optique quantique, sont demandeurs de nanoparticules présentant des propriétés optiques spécifiques. L'ablation laser en liquide, PLAL (Pulsed Laser Ablation induced in Liquid) est une méthode de synthèse permettant d'élaborer rapidement des nanoparticules dans une large gamme de matériaux, et donc de tester la conservation ou la modification des propriétés optiques originales identifiées dans certains matériaux lorsque l'on passe aux tailles nanométriques (scintillation, thermoluminescence, photo-stimulation, haut rendement de luminescence...). Dans ce travail de thèse la synthèse, la caractérisation optique et structurale de nanoparticules dopées a été développé. Différents types de matériaux ont été testés dont l'oxyde de gadolinium dopé, l'yttrium aluminium garnet (YAG), l'alumine etc. Cela a permis de montrer la faisabilité et la potentialité de cette technique d'élaboration sur différents matériaux. Par ailleurs un outil de diagnostic du plasma par spectroscopie optique résolue en temps a été mis en place afin de comprendre les processus des croissances des particules formées.

Investigation of magnetic proximity effect in ferromagnet/superconductor thin films by low temperature Magneto Optical Kerr Effect measurement

Radiative Decays of the phi-meson to the scalar mesons f0(980) and a0(980) are investigated within the framework of charged kaon loop model for both point-like scalar mesons and for scalar mesons with extended structure. Then, the radiative phi-meson decay into neutral K-meson is studied via a two step mechanism in which the scalar mesons couple the final state to the phi-meson through the charged kaon loop. The branching ratio of this decay is calculated and it is shown that this reaction will not provide a significant background to the measurements of phi-meson into neutral K-meson states decay for testing CP violation.

During the years between 1994 and 1997, the emulsion target of the CHORUS experiment was exposed to the wide band neutrino beam of the CERN SPS of 27 GeV average energy collecting about 106 neutrino interactions. A measurement of induced charm production and search for anticharmed pentaquark (0 c ) have been performed by using the presence of a 6% component in the beam. By requiring a positive muon charge as determined by the CHORUS muon spectrometer, 46 -induced charm events were observed with an estimated background of 5:20:4 events. At an average antineutrino energy of 18 GeV in the neutrino beam, the charm production rate induced by is

We present a search for scalar and tensor unparticles in the diphoton final state produced in pp collisions at a center-of-mass energy of 10 TeV, with the CMS detector at LHC. The analysis focuses on the data sample corresponding to the integrated luminosity of 100 pb&amp / #8722 / 1, expected to be collected in the first LHC run. The exclusion limits on unparticle parameters, scaling dimension dU and coupling constant lambda, and the discovery potential for unparticles are presented. This is the first simulation study of the sensitivity to unparticles decaying into the diphoton final state at a hadron collider.

The littlest Higgs model is one of the most economical solution to the hierarchy problem of the standard model. It predicts existence of new gauge vectors and also new scalars, neutral and charged. The littlest Higgs model predicts the existence of new scalars beside a scalar that can be assigned as Higgs scalar of the standard model. In this thesis, the production of scalars in $e^+e^-$ colliders is studied. The scalar productions associated with standard model Higgs boson are also analyzed. The effects of the parameters of the littlest Higgs model to these processes are examined in detail. The collider phenomenology of the littlest Higgs model is strongly dependant on the free parameters of the model, which are the mixing angles $s,s&#039 / $ and the symmetry breaking scale $f$. The parameters of the model are strongly restricted when the fermions are charged under only one $U(1)$ subgroup. In this thesis, by charging fermions under two $U(1)$ subgroups, the constraints on the symmetry braking scale and the mixing angles are relaxed. In the littlest Higgs model, the existence of charged heavy scalars also displays an interesting feature. By writing a Majorano like term in the Yukawa Lagrangian, these heavy charged scalars are allowed to decay in to lepton pairs, violating lepton number and flavor. In this thesis, the leptonic final states and also the lepton flavor and number violating final signals are also analyzed. As a result of these thesis, it is predicted that the scalar production will be in the reach for a $sqrt{S}=2TeV$ $e^+ e^-$ collider, giving significant number of lepton flavor violating signals depending on the Yukawa couplings of the flavor violating term.

In this thesis, we study the subject of geometrical phases in detail by considering its various forms. We focus primarily on the relation between quantum geometrical phases and magnetic monopoles, and study how one can make use of the concepts of geometrical phases to define magnetic monopoles.