Sökning: "Chiral Perturbation Theory"

Visar resultat 1 - 5 av 8 uppsatser innehållade orden Chiral Perturbation Theory.

  1. 1. Helicity amplitudes for the transition from the spin-3/2 Sigma to the Lambda hyperon

    Master-uppsats, Uppsala universitet/Kärnfysik

    Författare :Olov Junker; [2020]
    Nyckelord :hyperons; helicity amplitudes; dispersion theory; chiral perturbation theory;

    Sammanfattning : The helicity amplitudes of the scattering reaction Sigma* bar Lambda -> pi+ pi- at energies below 1 GeV are calculated. They are part of a project of determining the low energy Sigma* to Lambda transition form factors using dispersion theory. The helicity amplitudes require the Feynman amplitudes of Sigma* bar Lambda -> pi+ pi- as input. LÄS MER

  2. 2. Fitting the three loop pion mass and decay constant to lattice data

    Kandidat-uppsats, Lunds universitet/Teoretisk partikelfysik

    Författare :Alexandra Wernersson; [2019]
    Nyckelord :Chiral Perturbation Theory; Lattice QCD; pion mass; decay constant; three loop fit.; Physics and Astronomy;

    Sammanfattning : We perform a fit to three loop order (NNNLO) in Chiral perturbation theory of the pion mass and decay constant. In particular we investigate if the NNNLO fit is an improvement of the fit to two loop order (NNLO) to lattice QCD data, which was done in a lattice gauge group collaboration. LÄS MER

  3. 3. Updating bounds on the low-energy constants of Chiral Perturbation Theory from exact bounds on amplitudes

    Master-uppsats, Lunds universitet/Teoretisk partikelfysik; Lunds universitet/Institutionen för astronomi och teoretisk fysik

    Författare :Benjamin Alvarez; [2016]
    Nyckelord :Coupling constants; meson-meson scattering; Chiral perturbation theory; constraints.; Physics and Astronomy;

    Sammanfattning : Chiral perturbation theory is an efficient effective theory to describe meson-meson scattering at low energy. An effective theory naturally introduces low energy constants and they are used, for example, to solve the ultraviolet divergences. LÄS MER

  4. 4. Chiral Perturbation Theory for Neutron-Antineutron Oscillations

    Master-uppsats, Lunds universitet/Institutionen för astronomi och teoretisk fysik

    Författare :Erik Kofoed; [2016]
    Nyckelord :Neutron-antineutron Oscillations; Baryon Number Violation; Chiral Perturbation Theory; Effective Field Theory; Spurions; Physics and Astronomy;

    Sammanfattning : This thesis treats neutron-antineutron oscillations in the framework of chiral perturbation theory. An effective Lagrangian, using mesons and nucleons as degrees of freedom, is constructed to capture the low-energy behavior of the effective six-quark operators, which is the set of higher dimensional operators that can induce neutron to antineutron transitions at the quark level. LÄS MER

  5. 5. Dynamics of the η' meson at finite temperature

    Master-uppsats, Uppsala universitet/Kärnfysik

    Författare :Elisabetta Perotti; [2014]
    Nyckelord :effective field theory; chiral perturbation theory; resonance chiral theory; large Nc limit; chiral anomaly;

    Sammanfattning : At the present time it is unknown how the U(1)A anomaly of Quantum Chromodynamics behaves at high temperatures. We therefore want to look for thermal changes of the effects of the anomaly. LÄS MER