Massive Double Copy in Three Spacetime Dimensions

Understand

Recent explorations on how to construct a double copy of massive gauge fields have shown that, while any amplitude can be written in a form consistent with colour-kinematics duality, the double copy is generically unphysical.

• In this paper, we explore a new direction in which we can obtain a sensible double copy of massive gauge fields due to the special kinematics in three-dimensional spacetimes.
• To avoid the appearance of spurious poles at 5-points, we only require that the scattering amplitudes satisfy one BCJ relation.
• We show that the amplitudes of Topologically Massive Yang-Mills satisfy this relation and that their double copy at three, four, and five-points is Topologically Massive Gravity.