Effective Field Theories and Cosmological Scattering Equations

TL;DR

This paper develops worldsheet formulae for wavefunction coefficients in various scalar theories within de Sitter space, utilizing cosmological scattering equations and revealing a double copy structure.

Contribution

It introduces new worldsheet formulae for wavefunction coefficients of NLSM, DBI, and sGal theories in de Sitter space, and uncovers a double copy relation among them.

Findings

Derived explicit four-point integrands from simple building blocks.

Identified a double copy prescription linking NLSM, DBI, and sGal wavefunctions.

Analyzed soft limits showing they relate to boundary conformal generators.

Abstract

We propose worldsheet formulae for wavefunction coefficients of the massive non-linear sigma model (NLSM), scalar Dirac-Born-Infeld (DBI), and special Galileon (sGal) theories in de Sitter momentum space in terms of the recently proposed cosmological scattering equations constructed from conformal generators in the future boundary. The four-point integrands are assembled from simple building blocks and we identify a double copy prescription mapping the NLSM wavefunction coefficient to the DBI and sGal wavefunction coefficients, including mass deformations and curvature corrections. Finally, we compute the soft limits of these wavefunction coefficients and find that they can be written in terms of boundary conformal generators acting on contact diagrams.