Jutta Kunz

More about the q-deformed Poincaré algebra

Abstract The recently proposed deformed Poincare algebra is considered. Its structure is clarified and “unitary” representations are found. The contraction to the deformed Galilei algebra is performed. The three-dimensional counterpart is discussed.

The electroweak sphaleron at physical mixing angle

Abstract The electroweak sphaleron, known previously only in the spherical approximation at vanishing mixing, angle, is constructed for the physical value of the mixing angle sin2 θw=0.23. It is symmetric under rotations around the z-axis and parity reflections. Its energy density and total energy differ little from those of the spherical sphaleron.

Gravitating axially symmetric monopole-antimonopole chains and vortex rings

We discuss static axially symmetric solutions of 577(2) Yang-Mills-Higgs theory eouplcd to Einstein gravity. These regular asymptotically fiat solutions represent monopoles, monopole-antimonopole chains, vortex ring solutions as well as new configurations which appear only for large values of the Higgs self-coupling λ. The solutions are characterized by the node structure of the Higgs field, which vanishes at m isolated points for monopole- antimonopole chains, whereas for vortex rings it vanishes along one or more rings, centered around the symmetry axis.

Sphalerons in the Weak Interactions

’t Hooft (1976) observed that the standard model does not absolutely conserve baryon and lepton number due to the Adler-Bell-Jackiw anomaly The process ‘t Hooft considered was spontaneous fermion number violation due to instanton induced transitions. Attracting much attention Ringwald (1990) recently argued, that such tunnelling transitions between topologically distinct vacua might indeed be observable at high energies at future accelerators (Mattis and Mottola, 1990).

Weak Skyrmions and sphalerons

When the gauged non-linear σ-model is supplemented by a Skyrme term stable as well as unstable classical solutions exist: weak Skyrmions and sphalerons. Without the Skyrme term there remains only a sequence of sphalerons, which can be continued to finite Higgs masses. Here we investigate a model containing both, a finite Higgs mass and a Skyrme term. Stable weak Skyrmion solutions occur only above critical values of the Higgs mass and the Skyrme coupling constant.