Maximal trombone supergravity from wrapped M5-branes

TL;DR

This work constructs new maximally supersymmetric truncations of 11D supergravity to four dimensions, yielding D=4 N=8 theories with trombone gaugings in the TCSO(p,q,r;N) class. Using exceptional generalised geometry, the authors show that reductions on seven-manifolds of the form $G_3\rtimes S^4$ (and the direct product $G_3\times S^4$) give consistent truncations whose embedding tensors match the constant intrinsic torsion of a generalized identity structure, producing the four-dimensional trombone-gauged theory. They formulate two explicit twisted truncations corresponding to SLAG and A3C M5-brane solutions and prove that these, along with the direct-product truncation, are equivalent and yield the same maximal D=4 theory. Subsector analyses identify SLAG and A3C invariant sectors that uplift to AdS_4 near-horizon geometries, providing clear 11D embeddings for N=2 and N=1 subtheories with explicit uplifted metrics. Overall, the paper extends the landscape of known maximally supersymmetric truncations in M-theory and offers new AdS_4 backgrounds arising from wrapped M5-branes on special holonomy cycles.

Abstract

A new family of maximal supergravities in four dimensions, involving gaugings of the trombone scaling symmetry, has been recently introduced. Using exceptional generalised geometry, we show some supergravities in this class to arise by consistent truncation of $D=11$ supergravity. The seven-dimensional reduction manifold is locally equivalent to the topologically-twisted internal manifold of the AdS$_4$ geometries that arise near the horizon of M5-branes wrapped on supersymmetric three-cycles of special holonomy manifolds. The dimensional reduction involves a mixture of conventional and generalised Scherk-Schwarz prescriptions, and provides the first maximally supersymmetric consistent truncation to four dimensions in the context of the M5-brane.