arXiv subjects
Publications and source records attributed to J. Westphalen.
In a numerical Monte Carlo simulation of SU(2) Yang-Mills theory with light dynamical gluinos the low energy features of the dynamics as confinement and bound state mass spectrum are investigated. The motivation is supersymmetry at vanishing gluino mass. The performance of the applied two-step multi-bosonic dynamical fermion algorithm is discussed.
In a numerical Monte Carlo simulation of SU(2) Yang-Mills theory with dynamical gauginos we find evidence for two degenerate ground states at the supersymmetry point corresponding to zero gaugino mass. This is consistent with the expected pattern of spontaneous discrete chiral symmetry breaking $Z_4 \to Z_2$ caused by gaugino condensation.
We report on our experience with the two-step multi-bosonic algorithm in a large scale Monte Carlo simulation of the SU(2) Yang-Mills theory with dynamical gluinos. First results are described on the low lying spectrum of bound states, the string tension and the gluino condensate.
We discuss the possibility of extracting phase shifts from finite volume energies for meson-meson scattering, where the mesons are fermion-antifermion bound states of the massive Schwinger model with SU(2) flavour symmetry. The existence of analytical strong coupling predictions for the mass spectrum and for the scattering phases makes it possible to test the reliability of numerical results.
We report on a numerical investigation of the SU(2) gauge theory with gluinos. The low-lying spectrum in bosonic and fermionic channels is determined. Improvements of the multi-bosonic algorithm are discussed.
We extract scattering phases for fermion-fermion scattering from Monte Carlo simulations of the two-dimensional Gross-Neveu model. This is done by means of Lüscher's method, which exploits the volume dependence of the energies of two-particle states. The results are compared with the analytical predictions.
Encouraged by the successful applications of Lüscher's method to boson--boson scattering we discuss the possibility of extracting scattering phase shifts from finite--volume energies for fermion--fermion scattering in the Gross--Neveu model.
According to a proposal of Luescher it is possible to determine elastic scattering phases in infinite volume from the energy spectrum of two-particle states in a periodic box. We demonstrate the applicability of this method in the broken phase of the four-dimensional O(4) non-linear sigma-model in a Monte Carlo study on finite lattices. This non-perturbative approach also permits the study of unstable particles, the sigma-particle in our case. We observe the sigma-resonance and extract its mass and width. In all scattering channels investigated the results are completely consistent with perturbative calculations.
Using Luescher's method we determine the elastic scattering phases in the broken phase of the 4-dimensional O(4) non-linear sigma-model from the two-particle energy spectrum in a Monte-Carlo study on finite lattices. In the isospin-0-channel we observe the sigma-resonance and extract its mass and its width. In all scattering channels investigated the results are consistent with perturbative calculations.