Mass generation

Background

Electroweak theory and the Standard Model

Gravity-free models

Technicolor

Coleman-Weinberg mechanism

Other theories

• Unparticle physics and the unhiggs models posit that the Higgs sector and Higgs boson are scaling invariant, also known as unparticle physics.
• UV-Completion by Classicalization, in which the unitarization of the WW scattering happens by creation of classical configurations.
• Symmetry breaking driven by non-equilibrium dynamics of quantum fields above the electroweak scale.
• Asymptotically safe weak interactions based on some nonlinear sigma models.
• Models of composite W and Z vector bosons.
• Top quark condensate.

  Gravitational models

• Extra-dimensional Higgsless models use the fifth component of the gauge fields in place of the Higgs fields. It is possible to produce electroweak symmetry breaking by imposing certain boundary conditions on the extra dimensional fields, increasing the unitarity breakdown scale up to the energy scale of the extra dimension. Through the AdS/QCD correspondence this model can be related to technicolor models and to UnHiggs models, in which the Higgs field is of unparticle nature.
• Unitary Weyl gauge. If one adds a suitable gravitational term to the standard model action with gravitational coupling, the theory becomes locally scale-invariant in the unitary gauge for the local SU. Weyl transformations act multiplicatively on the Higgs field, so one can fix the Weyl gauge by requiring that the Higgs scalar be a constant.
• Preon and models inspired by preons such as the Ribbon model of Standard Model particles by Sundance Bilson-Thompson, based in braid theory and compatible with loop quantum gravity and similar theories. This model not only explains the origin of mass, but also interprets electric charge as a topological quantity, and colour charge as modes of twisting.
• In the theory of superfluid vacuum, masses of elementary particles arise from interaction with a physical vacuum, similarly to the gap generation mechanism in superfluids. The low-energy limit of this theory suggests an effective potential for the Higgs sector that is different from the Standard Model's, yet it yields the mass generation. Under certain conditions, this potential gives rise to an elementary particle with a role and characteristics similar to the Higgs boson.