Effective field theories and cosmological scattering equations

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.

Automated summary

In this paper, we propose worldsheet formulae for the wavefunction coefficients of the massive non-linear sigma model, scalar Dirac-Born-Infeld, and special Galileon theories in de Sitter momentum space. We also identify a double copy prescription that maps the wavefunction coefficient of the non-linear sigma model to the wavefunction coefficients of the Dirac-Born-Infeld and special Galileon theories.