Einstein-Yang-Mills-Dirac-Higgs theory

A theory in physics which describes the fundamental physics of the observable universe that would combine the following fields:

• Einstein - gravity

• Maxwell - electromagnetism

• Yang-Mills - electroweak and strong nuclear force

• Dirac - fermionic matter

• Higgs - scalar field

This would be a unified Einstein–Yang–Mills–Dirac–Higgs framework: general relativity coupled to the Standard Model's gauge fields, fermions, and the Higgs field. Electromagnetism would emerge from the electroweak sector after symmetry breaking. 

It would therefore provide a single classical field-theoretic description of gravity plus the Standard Model. However, General relativity is classically formulated and the Standard Model is a quantum field theory. Gravity works as an effective quantum field theory at low energies, but at energies approaching the Planck scale, the classical description of spacetime becomes inadequate. 

Matter would exist in dynamical spacetime. In ordinary particle physics, fields are formulated on a prescribed spacetime background. In Einstein's theory however, spacetime itself is dynamical. In the Einstein-Yang-Mills-Dirac-Higgs theory, matter field contribute to the stress energy tensor, i. e., the Higgs, the gauge fields and fermions all curve spacetime. The curvature of spacetime affects their propagation. Electromagnetism would become part of a larger gauge structure. Maxwell's theory would no longer appear as an isolated fundamental interaction rather, the photon emerges from electroweak mixing through the Higgs mechanism. 

The Higgs would also become part of spacetime physics, not a mere particle physics ingredient. There is a connection to cosmology here, that, the Higgs potential can have enormous energy densities under early-universe conditions. Thus, the Einstein-Yang-Mills-Dirac-Higgs theory connects particle physics, also with cosmology. 

There is also a particularly interesting bridge between differential geometry and field theory. Coupling topology to the field configurations they produce produces a response by spacetime structure. This is interesting as the Standard Model actually allows for some nontrivial field configurations, such as a sphaleron, a high energy field configuration in the electroweak theory. There are other nontrivial field configurations such as the magnetic monopoles. A classic example is the 't Hooft-Polyakov monopole, which has a topology allowing for stable monopoles. Another topological defect are cosmic strings, the electroweak string solution called Z-strings, configurations where the Z-field and Higgs field form a string structure. Z-strings differ from ordinary topological cosmic strings, in that, an electroweak Z-string can be unstable in the physics of the Standard Model. 

An Einstein-Yang-Mills-Dirac-Higgs theory would provide insight into a natural framework for cosmology also, as it would account for gravity, radiation, quarks, leptons, gauge fields and Higgs field, allowing for insight into the investigation of geometry, quantum fields and cosmic evolution. Gravitational effects associated with particle physics processes and the coupled evolution of these fields, would be carefully investigated.