- Study of multi-lepton final states with the ATLAS experiment: from Standard Model to Beyond Standard Model Higgs.
- Ucchielli, Giulia <1990>
Subject
- FIS/01 Fisica sperimentale
Description
- This thesis exploits the features of final states containing light leptons with same electric charge, produced in LHC proton-proton collisions at 13 TeV and collected by the ATLAS detector during the 2015 and 2016 data-taking. Events containing leptons with same electric charge allow to reject a substantial fraction of the background from the Standard Model processes. New physics is searched both indirectly and directly through two processes: the production of a Higgs boson in association with a pair of top quarks (ttH) and the production of new doubly charged Higgs bosons (H++). The measurement of the ttH signal strength (mu) into leptonic final states provides mu = 2.5 (+1.3 - 1.1), compatible at 95% confidence level with the Standard Model prediction mu(ttH) = 1. Regarding direct searches, no evidence for new physics is found in the search for H++ boson production: lower limits on its mass are set and vary from 770 GeV to 870 GeV at 95% confidence level.
Date
- 2018-04-18
Type
- Doctoral Thesis
- PeerReviewed
Format
- application/pdf
Identifier
urn:nbn:it:unibo-23876
Ucchielli, Giulia (2018) Study of multi-lepton final states with the ATLAS experiment: from Standard Model to Beyond Standard Model Higgs., [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Fisica