The double copy for heavy particles

TL;DR

This paper demonstrates a method to relate heavy particle theories in gauge and gravity contexts using the double copy approach, providing new all-order Lagrangians for spin-1 particles.

Contribution

It extends the double copy framework to Heavy Quark Effective Theory and Heavy Black Hole Effective Theory, including novel all-order Lagrangians for spin-1 particles.

Findings

Double copy relates HQET to HBET for spins up to 1.

Double copy of spin-1/2 HQET yields spin-1 HBET.

New all-order Lagrangians for spin-1 heavy particles.

Abstract

We show how to double-copy Heavy Quark Effective Theory (HQET) to Heavy Black Hole Effective Theory (HBET) for spin $s\leq 1$. In particular, the double copy of spin-$s$ HQET with scalar QCD produces spin-$s$ HBET, while the double copy of spin-1/2 HQET with itself gives spin-1 HBET. Finally, we present novel all-order-in-mass Lagrangians for spin-1 heavy particles.