Graviton as a Pair of Collinear Gauge Bosons

TL;DR

This paper demonstrates that certain mixed gravitational and gauge superstring amplitudes involving gravitons or dilatons decaying into gauge bosons can be expressed as linear combinations of open string amplitudes with collinear gauge bosons, revealing a new connection between closed and open string states.

Contribution

It introduces a novel representation of mixed superstring amplitudes, replacing gravitons or dilatons with pairs of collinear gauge bosons at the tree level.

Findings

Mixed amplitudes can be written as open string amplitude combinations.

Collinear gauge boson pairs carry half the original momentum.

Helicity configurations sum to match the original closed string state.

Abstract

We show that the mixed gravitational/gauge superstring amplitudes describing decays of massless closed strings - gravitons or dilatons - into a number of gauge bosons, can be written at the tree (disk) level as linear combinations of pure open string amplitudes in which the graviton (or dilaton) is replaced by a pair of collinear gauge bosons. Each of the constituent gauge bosons carry exactly one half of the original closed string momentum, while their +/- 1 helicities add up to +/- 2 for the graviton or to 0 for the dilaton.