Gluons and gravitons at one loop from ambitwistor strings

Understand

We present new and explicit formulae for the one-loop integrands of scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for any number of particles.

• The results exhibit the colour-kinematics duality in gauge theory and the double-copy relation to gravity, in a form that was recently observed in supersymmetric theories.
• The new formulae are expressed in a particular representation of the loop integrand, with only one quadratic propagator, which arises naturally from the framework of the loop-level scattering equations.
• The starting point in our work are the expressions based on the scattering equations that were recently derived from ambitwistor string theory.