ungauged

Ungauged is an adjective used in physics to describe a theory in which a global symmetry is not promoted to a local gauge symmetry. In an ungauged theory, there are no dynamical gauge fields associated with that symmetry, and the Lagrangian remains invariant under the global symmetry rather than under local gauge transformations. The term is often contrasted with gauged, where the symmetry becomes local and introduces gauge bosons and covariant derivatives.

Gauging is the procedure of turning a global symmetry into a local one by coupling the theory to gauge fields and promoting the symmetry parameters to functions of spacetime. This typically changes the structure of the theory, adding gauge interactions, covariant derivatives, and, in many cases, a scalar potential or mass terms. Ungauged theories retain the global symmetry and generally lack these additional gauge dynamics.

In practice, the distinction is common in gravity and high-energy theory. Ungauged supergravity refers to theories with extended global symmetries and no gauging of those symmetries; their Lagrangians usually feature no scalar potential arising from gauging. Gauged supergravity, by contrast, includes a potential and often modified fermion masses and couplings, reflecting the promoted local symmetry. The choice between ungauged and gauged formulations affects the space of vacua, supersymmetry breaking patterns, and the possible cosmological and phenomenological applications.

In string theory and related frameworks, ungauged effective theories can emerge from compactifications without fluxes that would gauge isometries. Introducing fluxes or other mechanisms can lead to gauged supergravity, altering the low-energy dynamics. Overall, ungauged highlights the absence of local gauge structure attached to a symmetry.