Symmetry Breaking in ordinary and supersymmetric Models of Quantum Field Theory
This thesis will consider two different theories, and apply variational techniques
to each, in order to investigate their true ground states and the possibility of
A scalar field theory is modified by introducing a variational mass-parameter,
which also serves as a regularization. The effective potential is calculated to two
loops, and a variational calculation is done to find the extrema of the potential.
Secondly, the model of Wess and Zumino is modified by removing the re-
strictions on the particle masses. The vacuum energy is then calculated to two
loops, and a variational calculation is performed with the renormalized masses
as parameters, in order to determine the true ground state of the theory.
It is discovered that the scalar field theory does not develop any symme-
trybreaking groundstates, as was predicted by Coleman and Weinberg. The
non-renormalization and vanishing vacuum energy of the Wess-Zumino model is
verifed to two-loop order. Furthermore, it is discovered that the modified Wess-
Zumino model has several groundstates which are more energetically favoured
than the supersymmetric state, in which supersymmetry is strongly broken.
This may begin explain, if they exist, why we do not see any supersymmetric
partners in our accelerators.
Place, publisher, year, edition, pages
Institutt for fysikk , 2012. , 89 p.
ntnudaim:6694, MFY Fysikk,
IdentifiersURN: urn:nbn:no:ntnu:diva-16794Local ID: ntnudaim:6694OAI: oai:DiVA.org:ntnu-16794DiVA: diva2:536464
Olaussen, Kåre, Professor