Global ETD Search

1	Modelo Lepto-fóbico com um bóson Z : Análise sobre possível evidência de matéria escura. Oliveira, Jardson Ricardo de Souza 01 March 2013 (has links) Made available in DSpace on 2015-05-14T12:14:11Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 626469 bytes, checksum: b00f1a4159fa8427d51e0806ea431c8f (MD5) Previous issue date: 2013-03-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Standard Model with its current simmetry, is complete, but still not the final word for the study of elementary particle physics, and many of the experiments show an accumulation of data indicating the existence of DarkMatter, i.e., new physics that can not be described only by it; in mid-2009 , an excess in the fraction of the flow of electron/positron experiments measured by the PAMELLA[1], FERMI[2] and HESS[3], experiments that could be interpreted as possible evidence of dark matter annihilation through Lepto-phobic interaction, instigated researchers. Therefore, to describe such a scenario, the following will consider the extension of the standard model with the gauge group ULi−Lj (1)[4], for an analysis of how this can help solve this problem of excessive flow detected. / O Modelo Padrão com sua simetria atual, está completo, porém ainda não é a palavra final para o estudo de física de física das partículas elementares, muitos dos experimentos realizados apresentam uma acumulação de dados que denotam a existência de Matéria Escura, ou seja, apontam para física nova que não pode ser descrita somente por ele; em meados de 2009, um excesso na fração do fluxo elétron/pósitron medida pelos experimentos do PAMELA[1],FERMI-Lat[2] e HESS[3], que puderam ser interpretados como possíveis evidências de aniquilação de matéria escura através de interação lepto-fóbica, instigaram os pesquisadores. Portanto, para descrever tal cenário, a seguir considerar-se-á a extensão do Modelo Padrão com o grupo de gauge ULi−Lj (1)[4], para uma análise de como este pode ajudar a resolver esse problema do fluxo excessivo detectado. Modelo Padrão Extensão do modelo Hipercarga Matéria Escura Aniquilação Bóson Z Standard Model Model Extension of the model Hypercharge Dark Matter Annihilation Z boson CIENCIAS EXATAS E DA TERRA::FISICA
2	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 dark sector dark photon ATLAS LHC Higgs boson Higgs BSM SM Standard Model beyond the Standard Model search Zd Zdark Large Hadron Collider electrons muons Higgs decays hidden sector kinetic mixing Higgs mixing U(1) hypercharge Higgs portal dark matter symmetry breaking data-driven fake background Z_d detector particle physics hep hep-ex high energy physics CERN run-2 fake factor

Search results

Modelo Lepto-fóbico com um bóson Z : Análise sobre possível evidência de matéria escura.

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