Sökning: "Invariant coupling"

Hittade 5 uppsatser innehållade orden Invariant coupling.

  1. 1. 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

  3. 2. 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

  4. 3. A study of Spontenous CP Violation in the Scale Invariant 2HDM

    Kandidat-uppsats, Lunds universitet/Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation

    Författare :Jimmy Gunnarsson; [2022]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : In this thesis, we study the Higgs mass spectrum and spontaneous CP violation, where one of the Higgs vacuum expectation values acquires a non-trivial phase θ in a Type-I 2HDM. We begin by investigating CP violating effects at tree-level, and then expand our studies by taking into account one-loop radiative corrections. LÄS MER

  5. 4. Signal background interference effects in lepton trident events with a new low mass mediator

    Master-uppsats, Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

    Författare :Patricia Andrea Gutiérrez García; [2020]
    Nyckelord :dark matter; pythia; matrix element corrections; LDM; Dire; Madgraph; dark photons; Physics and Astronomy;

    Sammanfattning : In this project we present a phenomenological study of signal to background interference effects in leptonic tridents produced in parton showers. The interference effects are introduced by linking matrix element corrections of a kinetically mixed dark photon model to the parton shower Dire. LÄS MER

  7. 5. On tensor product of non-unitary representations of sl(2,R)

    Magister-uppsats, Institutionen för ingenjörsvetenskap, fysik och matematik

    Författare :Carl Stigner; [2007]
    Nyckelord :sl 2; R ; Lie algebra; Representation theory; Tensor product representations; Non-compact algebra; Invariant coupling; Infinitesimal character;

    Sammanfattning : The study of symmetries is an essential tool in modern physics. The analysis of symmetries is often carried out in the form of Lie algebras and their representations. Knowing the representation theory of a Lie algebra includes knowing how tensor products of representations behave. LÄS MER