Sökning: "Higgs boson"

Visar resultat 1 - 5 av 66 uppsatser innehållade orden Higgs boson.

1. 1. Defining dark jets at the particle level

   Master-uppsats, Lunds universitet/Partikel- och kärnfysik; Lunds universitet/Fysiska institutionen

   Författare :Gustav Lindberg; [2023]
   Nyckelord :Particle physics; Dark matter; QCD; Physics and Astronomy;

   Sammanfattning : One hypothesis that attempts to explain dark matter is dark QCD, which suggests that there would be a dark sector made up of dark quarks. Dark quarks would interact with each other through dark QCD similar to how Standard Model quarks interact with each other through Standard Model QCD. LÄS MER

3. 2. Constraining the Higgs width in Higgs production associated with a top quark pair

   Kandidat-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

   Författare :Benjamin Dahlén; [2023]
   Nyckelord :Higgs; width; cross section; on-shell; off-shell; invariant mass; Standard model; upper bound; Physics and Astronomy;

   Sammanfattning : In this thesis we study the width of the Higgs boson in the process pp → t ̄t 4l at LO using MadGraph5_aMC@NLO to generate the events. The contributions including the Higgs signal, continuum background and interference were considered in order to calculate the expected number of events in a broad range of four-lepton invariant masses. LÄS MER

4. 3. Event categorisation and Machine-learning Techniques in Searches for Higgs Boson Pairs in the ATLAS Experiment at the LHC

   Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Högenergifysik

   Författare :Milads Emadi; [2023]
   Nyckelord :Particle Physics; ATLAS; BDT; Boosted Decision Tree; Decision Tree; Optimization; Machine Learning; Analysis;

   Sammanfattning : This thesis investigates the pair production of Higgs bosons (di-Higgs events) at the ATLAS experiment in the Large Hadron Collider (LHC), focusing on the channel where one Higgs boson decays into two bottom quarks and the other decays into two tau leptons. The main objective was to determine whether introducing a split in the invariant mass of the decay products from the two Higgs bosons (the di-Higgs mass) and using this as an analysis variable improves the sensitivity of the Boosted Decision Tree (BDT) machine learning algorithm to the di-Higgs signal. LÄS MER

5. 4. Determining backgrounds with misidentified leptons in the ATLAS Higgs boson analysis

   Master-uppsats, KTH/Fysik

   Författare :Leo Qiyuan Hu; [2023]
   Nyckelord :Particle Physics; ATLAS detector; Fake Factor method; Higgs boson; lepton misreconstruction; misidentified events; Partikelfysik; ATLAS detektorn; Fake Factor-metoden; Higgs boson; lepton felrekonstruktion; felidentifierade händelser;

   Sammanfattning : This thesis presents an analysis of misidentified leptons in the Higgs boson decaychannel H → W W ∗ → lνlν. Misidentified leptons, resulting from jets misidentifiedas leptons, mimic the signal of a Higgs boson decay, resulting in a backgroundcontribution to the signal. LÄS MER

7. 5. The Higgs Width in Higgs production in association with a W+ boson

   Kandidat-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

   Författare :Wijeratne Mohandiramge Umashi Navisha Fernando; [2023]
   Nyckelord :Higgs boson; Higgs width; off-shell; on-shell; narrow-width approximation; MadGraph5_MC@NLO; W boson; supersymmetry; dark matter; Physics and Astronomy;

   Sammanfattning : The width of the Higgs boson is a quantity that cannot be measured directly from the on-shell Higgs peak; it would have to be measured indirectly. In 2013, Caola and Melnikov developed a method to determine the Higgs width by using off-shell and on-shell cross-sections and applying the narrow-width approximation. LÄS MER