Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Experimental Particle Physics

Weak Force

The weak interaction is responsible for our existence but cannot been directly experienced in our all day life.  The decay of particles and nuclei can be explained by the exchange of W- and Z-bosons, the intermediate particles of the weak force.  Accordingly, during the interaction with the W- and Z-boson the identity of quarks and leptons can be changed.  In contrast to the strong and electromagnetic interaction, the intermediate bosons of the weak interaction are massive causing a fundamental break of the symmetry principle of the Standard Model.  To explain their large masses the existence of an additional field, the Higgs field, is neccessary.  Furthermore, there is a common theory unifying the electromagnetic and weak interactions, the Theory of electroweak interactions.  This unification could already been measured in experiments.

In nature exists an other fundamental symmetry, the symmetry of matter and antimatter.  It could be observed in weak interactions that this is slightly violated in favour of matter, which is one of the reasons for the existence of our universe.

Forces | Strong Force | Weak Force | Symmetry | Symmetry Breaking