Symmetry and Unification from Soft Theorems and Unitarity

Understand

We argue that symmetry and unification can emerge as byproducts of certain physical constraints on dynamical scattering.

• To accomplish this we parameterize a general Lorentz invariant, four-dimensional theory of massless and massive scalar fields coupled via arbitrary local interactions.
• Assuming perturbative unitarity and an Adler zero condition, we prove that any finite spectrum of massless and massive modes will necessarily unify at high energies into multiplets of a linearized symmetry.
• Certain generators of the symmetry algebra can be derived explicitly in terms of the spectrum and three-particle interactions.