On loop celestial amplitudes for gauge theory and gravity

TL;DR

This paper explores loop-level celestial amplitudes for gluons and gravitons, focusing on finite all-plus and single-minus helicity configurations, providing explicit four- and five-point examples and insights into higher points.

Contribution

It presents the first explicit calculations of finite loop-level celestial amplitudes for Yang-Mills and gravity beyond tree level, focusing on specific helicity configurations.

Findings

Explicit four-point celestial amplitudes for gluons and gravitons.

Five-point celestial amplitude examples provided.

Discussion on potential higher-point amplitudes.

Abstract

Scattering amplitudes of massless particles in Minkowski space can be expressed in a conformal basis by Mellin transforming the momentum space amplitudes to correlation functions on the celestial sphere at null infinity. In this paper, we study celestial amplitudes of loop level gluons and gravitons. We focus on the rational amplitudes that carry all-plus and single-minus external helicities. Because these amplitudes are finite, they provide a concrete example of celestial amplitudes of Yang- Mills and gravity theory beyond tree level. We give explicit examples of four and five point functions and comment on higher point amplitudes.