Explicit BCJ Numerators from Pure Spinors

TL;DR

This paper derives local kinematic numerators for gauge theory amplitudes from superstring theory using pure spinors, revealing a natural color-kinematics duality that applies across various supersymmetry levels and helicity configurations.

Contribution

It introduces a method to obtain explicit BCJ numerators from pure spinor superstring amplitudes, demonstrating their universality and manifest Jacobi identities.

Findings

Kinematic numerators satisfy Jacobi identities similar to color factors.

The approach applies to all N^kMHV helicity configurations.

Color-kinematics duality emerges naturally from superstring computations.

Abstract

We derive local kinematic numerators for gauge theory tree amplitudes which manifestly satisfy Jacobi identities analogous to color factors. They naturally emerge from the low energy limit of superstring amplitudes computed with the pure spinor formalism. The manifestation of the color--kinematics duality is a consequence of the superstring computation involving no more than (n-2)! kinematic factors for the full color dressed n-point amplitude. The bosonic part of these results describe gluon scattering independent on the number of supersymmetries and captures any N^kMHV helicity configuration after dimensional reduction to D=4 dimensions.