Cosmological Cutting Rules from Flat-Space Unitarity via Dressing

TL;DR

This paper derives cosmological cutting rules from flat-space unitarity principles, providing a clear diagrammatic understanding and explicit examples at tree and one-loop levels for conformally coupled scalars.

Contribution

It introduces a novel approach to derive cosmological cutting rules from flat-space unitarity using dressing rules, clarifying their diagrammatic origin.

Findings

Derived cosmological cutting rules from flat-space unitarity.

Mapped Cutkosky delta functions to 'Disc' operations in energy variables.

Provided explicit tree-level and one-loop examples for conformally coupled scalars.

Abstract

Using cosmological dressing rules, we uplift flat-space unitarity cuts to discontinuity relations for dS/EAdS observables. In this representation, Cutkosky delta functions map directly to "Disc" operations in the exchanged energy variable. This provides a transparent diagram by diagram origin of cosmological cutting rules. We illustrate this with explicit examples at tree level and one loop for conformally coupled scalars.