Reliability of dimensional regularization for branch cuts at higher loop orders

Determine whether dimensional regularization can reliably compute total-energy branch cuts in de Sitter correlators at higher loop orders and thereby enable a straightforward generalization of flat-space limits to multi-loop correlators.

Background

The paper shows that at 1-loop, dimensional regularization reproduces branch cuts in agreement with diagrammatic expectations and supports the flat-space limit correspondence, but notes scheme-dependent subtleties.

They explicitly identify the need to confirm that dimensional regularization remains reliable for computing branch-cut structures at higher loops to extend the flat-space limit beyond one loop.

References

It also remains an open question whether our dimensional-regularization approach can reliably compute branch cuts at higher loop orders, which would pave the way for a straightforward generalization of flat-space limits to multi-loop correlators.

— Singularities in Cosmological Loop Correlators II : Non Local Interactions and Flat Space limits  (2512.11040 - Ansari et al., 11 Dec 2025) in Section 6 (Conclusion)