Sekoituskulma

Sekoituskulma, also known as the mixing angle, is a concept in particle physics that describes the degree to which fundamental particles are mixed. It arises in theories that go beyond the Standard Model, particularly in extensions that involve more than one Higgs boson or other new scalar particles. The mixing angle quantifies how the mass eigenstates of these particles are related to their interaction eigenstates.

In a simplified two-Higgs doublet model, for instance, there are typically five Higgs bosons: two neutral CP-even scalars (h1 and h2), one neutral CP-odd scalar (A), and a pair of charged scalars (H+ and H-). The mass eigenstates of the two neutral CP-even scalars are linear combinations of the original interaction eigenstates. The sekoituskulma, often denoted by a Greek letter like alpha (α), is the parameter that determines the coefficients of these linear combinations.

The value of the mixing angle is not predicted by the theory itself and must be determined experimentally. Measurements of Higgs boson production and decay rates, as well as searches for additional Higgs bosons, can constrain or determine the sekoituskulma. Different values of the mixing angle can lead to distinct observable phenomena, such as variations in the branching ratios of Higgs boson decays or the presence of additional Higgs-related signals. Understanding the sekoituskulma is crucial for testing the validity of extended Higgs sectors and for searching for new physics beyond the Standard Model.