Sökning: "bosons"

Visar resultat 1 - 5 av 65 uppsatser innehållade ordet bosons.

1. 1. Exploring electroweak symmetry breaking in the scale-invariant Two-Higgs-Doublet Model

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

   Författare :Erik Rustas; [2023]
   Nyckelord :Two-Higgs-Doublet Models; 2HDM; Scale-invariance; Baryogenesis; BSM; Baryon Asymmetry; Coleman-Weinberg Potential; Theoretical Particle Physics; Physics and Astronomy;

   Sammanfattning : This thesis investigates the properties of a general scale-invariant Two-Higgs-Doublet Model and its phenomenological consequences with focus on the scalar sector. The concept suggests that introducing more CP-violation, both spontaneous and explicit, may make it possible to meet the Sakharov conditions and account for the Universe's baryon asymmetry. 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. Asymptotic Symmetries and Dressed States in QED and QCD

   Master-uppsats, Stockholms universitet/Fysikum

   Författare :Saimeng Zhou; [2023]
   Nyckelord :Dressed states; Large gauge transformation; Faddeev-Kulish formalism; Generalized coherent state operator; Wilson line; Infrared divergence; Asymptotic Hamiltonian; QED; QCD;

   Sammanfattning : Infrared divergences arising in theories with massless gauge bosons have been shown to cancel in scattering amplitudes when using dressed states constructed from the Faddeev- Kulish approach to the asymptotic states. It has been established that these states are closely related to asymptotic symmetries of the theory, that is, non-vanishing gauge trans- formations at the asymptotic boundary. LÄS MER

5. 4. 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

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