Graviton loops and brane observables
R. Contino, L. Pilo, R. Rattazzi, A. Strumia
TL;DR
The paper develops a fully covariant effective field theory framework for gravitons interacting with branes in compact extra dimensions, highlighting the essential role of brane fluctuations (branons) and a proper gauge/regularization strategy. By fixing the $D$-dimensional gauge via the Faddeev–Popov procedure, using a covariant regulator, and carefully identifying physical observables, it demonstrates that spurious gauge and infrared artifacts cancel in physical quantities, even though naive quantities like the Higgs mass or oblique parameters can appear gauge dependent. The authors show that, within this framework, one‑loop graviton corrections to brane observables are dominated by calculable infrared contributions and that UV-sensitive pieces must be parameterized by a cutoff $\\\Lambda$, consistent with EFT limits. They illustrate the methodology with a brane on a torus, where the leading corrections to brane scalar masses arise from graviton diagrams and are constrained by the brane tension and KK sum, informing phenomenology for electroweak precision tests and muon $g-2$ in large extra dimension scenarios.
Abstract
We discuss how to consistently perform effective Lagrangian computations in quantum gravity with branes in compact extra dimensions. A reparametrization invariant and infrared finite result is obtained in a non trivial way. It is crucial to properly account for brane fluctuations and to correctly identify physical observables. Our results correct some confusing claims in the literature. We discuss the implications of graviton loops on electroweak precision observables and on the muon g-2 in models with large extra dimensions. We model the leading effects, not controlled by effective field theory, by introducing a hard momentum cut-off.