Broken Weyl Gravity: Dynamical Torsion and Generalized Proca

Abstract

We develop a symmetry-based construction of gravity from a phase in which Weyl invariance is spontaneously broken. Using the coset formalism, the dilaton acts as a Stuckelberg field for the gauged scale symmetry, giving the Weyl gauge field a mass of order $\mathcal{O}(M_{\rm Pl})$. The resulting gauge-gravity interactions fall within the ghost-free generalized Proca framework. We further show that the Weyl field can be exchanged for a propagating vector component of torsion, providing a natural realization of dynamical vector torsion. Our construction organizes all operators systematically, clarifies the absence of Wess-Zumino terms in $d=4$, and recovers General Relativity in the infrared with controlled higher-derivative corrections.