Yukawakopplingskonstanterna

Yukawakopplingskonstanterna, often referred to as Yukawa couplings, are fundamental constants in particle physics that describe the strength of the interaction between fermions and scalar or pseudoscalar mesons. These couplings are named after the Japanese physicist Hideki Yukawa, who first proposed them in his theory of nuclear forces in the 1930s. The Yukawa interaction is a type of potential energy that arises from the exchange of virtual particles.

In the context of the Standard Model of particle physics, Yukawa couplings are particularly important for understanding the masses of elementary particles. Specifically, they govern the interactions between quarks and leptons (like electrons and neutrinos) and the Higgs boson. When the Higgs field acquires a vacuum expectation value, it breaks electroweak symmetry, and these couplings determine how strongly each fermion interacts with the Higgs field. This interaction strength is directly proportional to the mass of the fermion. Particles with larger Yukawa couplings interact more strongly with the Higgs field and thus are more massive.

The values of the Yukawa coupling constants are not predicted by the Standard Model itself but must be determined experimentally. These constants vary significantly across different fermions, with the top quark having the largest known Yukawa coupling, close to one, while the electron has a very small coupling. Understanding the full spectrum of Yukawa couplings and their origin remains a significant challenge and an active area of research in theoretical physics, with many extensions to the Standard Model attempting to explain these values.