Descendants in celestial CFT and emergent multi-collinear factorization

TL;DR

This paper explores how locality and unitarity emerge in celestial CFT through multi-collinear limits, using asymptotic symmetries and OPE techniques to compute gluon and graviton amplitudes, confirming consistency with known results.

Contribution

It introduces a new holographic method leveraging celestial OPEs and asymptotic symmetries to compute multi-collinear limits of scattering amplitudes.

Findings

OPE predictions match Mellin transform results to all orders in descendants

Consistent leading-order double-collinear limits for gravitons

New recursive approach for computing multi-collinear gluon amplitudes

Abstract

Multi-collinear factorization limits provide a window to study how locality and unitarity of scattering amplitudes can emerge dynamically from celestial CFT, the conjectured holographic dual to gauge and gravitational theories in flat space. To this end, we first use asymptotic symmetries to commence a systematic study of conformal and Kac-Moody descendants in the OPE of celestial gluons. Recursive application of these OPEs then equips us with a novel holographic method of computing the multi-collinear limits of gluon amplitudes. We perform this computation for some of the simplest helicity assignments of the collinear particles. The prediction from the OPE matches with Mellin transforms of the expressions in the literature to all orders in conformal descendants. In a similar vein, we conclude by studying multi-collinear limits of graviton amplitudes in the leading approximation of sequential double-collinear limits, again finding a consistency check against the leading order OPE of celestial gravitons.