Renormalisierbar

Renormalisierbar is a German term that translates to "renormalizable" in English. In the context of physics, particularly quantum field theory, a theory is considered renormalizable if its infinities, which arise during calculations, can be systematically absorbed into a finite number of physical parameters. These parameters, such as mass and charge, are then determined by experimental measurement, rather than being predicted by the theory itself.

The concept of renormalization is crucial for making predictions in quantum field theories. Without it, calculations would yield nonsensical infinite results. A theory is deemed renormalizable if the number of these "counterterms," needed to cancel the infinities, is finite and independent of the energy scale at which the calculations are performed. Theories that require an infinite number of counterterms are called non-renormalizable and are generally considered less fundamental or predictive at very high energies.

The Standard Model of particle physics is a prime example of a renormalizable theory. Its success in describing the fundamental forces (except gravity) and elementary particles is largely due to its renormalizability. This property allows physicists to make precise predictions that can be tested against experimental data. The development of the renormalization group, a mathematical framework that describes how physical quantities change with energy scale, was a significant step in understanding and applying renormalization.