Compactified 2HDM under the Non-SUSY AdS instability conjecture
M. A. Rbah, S. Saoud, R. Sammani, E. H. Saidi, R. Ahl Laamara
TL;DR
This work studies a compactified Two-Higgs-Doublet Model (2HDM) coupled to gravity on a circle, deriving a full three-dimensional effective action that includes tree-level Higgs terms, one-loop Kaluza-Klein corrections, and a Goldberger–Wise–inspired radion potential. By enforcing the non-supersymmetric AdS instability conjecture from the Swampland program, the authors find a model-independent lower bound on the heavy-Higgs mass, $M_H \gtrsim 680\,\mathrm{GeV}$, to avoid unstable AdS$_3$ vacua. The analysis demonstrates how extra-dimensional dynamics and quantum-gravity consistency conditions can yield sharp, testable predictions for extended Higgs sectors, linking radion stabilization and Higgs phenomenology to potential collider signatures around the 600–700 GeV range. Overall, the paper provides a controlled framework where Swampland-inspired constraints translate into concrete phenomenological bounds on the Higgs spectrum.
Abstract
We investigate how extra-dimensional dynamics influence the Higgs sector phenomenology by compactifying a Two-Higgs-Doublet Model (2HDM) coupled to 4D gravity on a circle $S^{1}$. The resulting effective potential includes tree-level 2HDM interactions, one-loop Coleman-Weinberg corrections from the Kaluza-Klein towers, and a radion contribution inspired by the Goldberger-Wise mechanism. We derive the full 3D effective action and show that, for the observed Higgs mass $m_{h}=125$ GeV, the radion potential admits a stable minimum, near-zero vacuum energy. By imposing the non-supersymmetric AdS instability conjecture as a quantum gravity consistency requirement, we obtain a model independent bound on the heavy Higgs sector, finding that the additional scalar states must satisfy $M_{H}\gtrsim 680$ GeV to avoid an unstable AdS$_{3}$ vacuum. Our results demonstrate how Swampland inspired constraints can yield sharp, phenomenologically testable predictions for extended Higgs sectors.
