Search for dissertations about: "loop amplitudes"

Showing result 1 - 5 of 13 swedish dissertations containing the words loop amplitudes.

  2. 1. Maximal Unitarity at Two Loops : A New Method for Computing Two-Loop Scattering Amplitudes

    Author : Kasper J. Larsen; Lisa Freyhult; David Kosower; Joseph Minahan; Paul Heslop; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Amplitudes; NNLO calculations; Quantum Chromodynamics; Unitarity; Fysik med inriktning mot elementarpartikelfysik; Physics with specialization in Elementary Particle Physics;

    Abstract : The study of scattering amplitudes beyond one loop is necessary for precision phenomenology for the Large Hadron Collider and may also provide deeper insights into the theoretical foundations of quantum field theory. In this thesis we develop a new method for computing two-loop amplitudes, based on unitarity rather than Feynman diagrams. READ MORE

  4. 2. The Chirality-Flow Formalism and Optimising Scattering Amplitudes

    Author : Andrew Lifson; Partikel- och kärnfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Spinor-helicity formalism; Chirality-flow formalism; Helicity amplitudes; Standard Model; QED; QCD; Optimisations; Colour expansion; Phenomenology; Fysicumarkivet A:2023:Lifson;

    Abstract : This thesis is composed of five papers, which all attempt to optimise calculations of scattering amplitudes in high-energy-physics collisions. These scattering amplitudes are a key part of theoretical predictions for particle-physics experiments like the Large Hadron Collider at CERN. READ MORE

  5. 3. On applications of manifest, maximal supersymmetry & U-duality

    Author : Anna Karlsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; maximal supergravity; pure spinors; Maximal supersymmetry; loop amplitudes; U-duality; Born-Infeld theory; generalised geometry; high energy particle physics;

    Abstract : Maximal supersymmetry is made manifest through the introduction of the pure spinor formalism. In many ways, this formalism represents a powerful tool in examinations of characteristics of different theories in high energy physics, though it is far from extensively exploited. READ MORE

  6. 4. Off-shell, maximal supersymmetry & exceptional geometry

    Author : Anna Karlsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Maximal supersymmetry; pure spinors; exceptional geometry; maximal supergravity; loop amplitudes; U-duality; high energy particle physics;

    Abstract : Two lines of research are presented in this thesis, both with a focus on fundamental properties within the supersymmetric theories of high energy physics. The first features analyses based on the actions for maximal supersymmetric Yang–Mills theory and supergravity, provided by the pure spinor formalism. READ MORE

  7. 5. Multi-Meson Dynamics in Chiral Perturbation Theory

    Author : Mattias Sjö; Partikel- och kärnfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Spridningsamplituder; Effektiv Fältteori; Spontant symmetribrott; Ickelinjära sigmamodellen; Kirala Lagrangianer; Hadronspektroskopi; Strukturer och Interaktioner; Gitter-QCD; Scattering amplitudes; Effective Field Theories; Spontaneous Symmetry Breaking; Nonlinear sigma model; Chiral Lagrangians; Hadronic Spectroscopy; Structure and Interactions; Lattice QCD;

    Abstract : This thesis concerns scattering of light mesons in the case where the number of external particles exceeds four (that is, three or more particles in the initial or final state), calculated using chiral perturbation theory.This is both of theoretical interest in the study of scattering amplitudes, and relevant for systems of three or more pions simulated using lattice quantum chromodynamics. READ MORE