Extended Massive Ambitwistor String

TL;DR

This paper introduces a variation of the massive ambitwistor string model that unifies supergravity and super-Yang-Mills theories, providing explicit amplitude calculations and analyzing their properties including unitarity and the massless limit.

Contribution

It presents a new version of the ambitwistor string model that describes multiple theories simultaneously with a single Lagrangian, and evaluates key scattering amplitudes.

Findings

All-multiplicity tree and one-loop amplitudes have proper unitarity factorization.

The massless limit reproduces Einstein-Yang-Mills amplitudes with multiple gluon traces.

The cosmological constant is argued to vanish at all perturbative orders.

Abstract

This work considers a variation of the massive ambitwistor string model presented in arXiv:2301.11227 that describes supergravity and super-Yang-Mills on the Coulomb branch simultaneously with a single Lagrangian. All-multiplicity tree and one-loop amplitudes are evaluated and shown to have proper unitary factorization. The massless limit provides Einstein Yang-Mills Amplitudes including multiple gluon traces. It is argued that the cosmological constant vanishes at all orders of perturbation theory. As application, results for Compton scattering are obtained and compared with ones in the literature.