Resumen de Search for long-lived particles decaying into displaced dilepton vertices in proton-proton collisions at √s = 13 TeV with the CMS detector

Celia Fernández Madrazo

• español

  Una de las extensiones más populares del Modelo Estándar son las partículas de alta vida media. El trabajo presentado en esta tesis consiste en una búsqueda de partículas de alta vida media en su canal de desintegración a estados finales con un vértice dileptónico desplazado. En esta búsqueda, se analizan colisiones protón-protón a una energía de centro de masas de 13 TeV, producidas en el LHC del CERN y detectadas en el detector CMS en 2016, 2017 y 2018. Los leptones en este análisis emergen de un vértice desplazado del punto de interacción, por lo que se reconstruyen con algoritmos especializados para ello. La búsqueda se ha diseñado para cubrir un amplio rango de masa y obtener resultados para un rango de vida media de 0.1 cm a 1000 cm. Los datos observados son compatibles con las predicciones del Modelo Estándar. Se han obtenido límites de exclusión para un modelo de bosones de Higgs exóticos en su desintegración a bosones escalares. Los resultados son competitivos con resultados similares obtenidos por CMS y ATLAS y, en particular, representan los mejores límites para el canal de electrones.

  Some of the most popular extensions of the Standard Model contain long-lived particles. This thesis presents a search for long-lived particles decaying into final states with a displaced dilepton vertex. It analyzes proton-proton collisions at a center-of-mass energy of 13 TeV that were produced at the CERN LHC and collected by the CMS detector in 2016, 2017 and 2018. Leptons in this analysis emerge from a vertex displaced from the interaction point and need to be reconstructed with special algorithms. The search is designed to cover a wide mass range, and be sensitive to lifetimes from 0.1 cm to 1000 cm. In the analysis, observed data are found to be in good agreement with the Standard Model expectations. Upper limits have been obtained for a model with an exotic Higgs boson decaying into two scalar long-lived particles. These results are competitive with similar results shown by the CMS and ATLAS collaborations, and in particular they provide the most stringent limits for the electron channel.

• English

  Some of the most popular extensions of the Standard Model contain long-lived particles. This thesis presents a search for long-lived particles decaying into final states with a displaced dilepton vertex. It analyzes proton-proton collisions at a center-of-mass energy of 13 TeV that were produced at the CERN LHC and collected by the CMS detector in 2016, 2017 and 2018. Leptons in this analysis emerge from a vertex displaced from the interaction point and need to be reconstructed with special algorithms. The search is designed to cover a wide mass range, and be sensitive to lifetimes from 0.1 cm to 1000 cm. In the analysis, observed data are found to be in good agreement with the Standard Model expectations. Upper limits have been obtained for a model with an exotic Higgs boson decaying into two scalar long-lived particles. These results are competitive with similar results shown by the CMS and ATLAS collaborations, and in particular they provide the most stringent limits for the electron channel.