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arXiv · 1904.10831

Conformally Soft Theorem in Gauge Theory

Monica Pate·Ana-Maria Raclariu·Andrew Strominger
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Abstract

Asymptotic particle states in four-dimensional celestial scattering amplitudes are labelled by their $SL(2,\mathbb{C})$ Lorentz/conformal weights $(h,\bar{h})$ rather than the usual energy-momentum four-vector. These boost eigenstates involve a superposition of all energies. As such, celestial gluon (or photon) scattering cannot obey the usual (energetically) soft theorems. In this paper we show that tree-level celestial gluon scattering, in theories with sufficiently soft UV behavior, instead obeys conformally soft theorems involving $h \to 0$ or $\bar{h} \to 0$. Unlike the energetically soft theorem, the conformally soft theorem cannot be derived from low-energy effective field theory.

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Monica Pate, Ana-Maria Raclariu, Andrew Strominger. 2019-04-24. Conformally Soft Theorem in Gauge Theory. https://doi.org/10.1103/physrevd.100.085017

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