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Bibliographic Details
Main Author: Georgiou, George
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2408.03673
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Table of Contents:
  • In contradistinction to the case of massive excitations, the connection between integrability and the tree-level massless scattering matrix of integrable $σ$-models is lost. Namely, in well-known 2-d integrable models the tree-level massless S-matrix exhibits particle production and fails to factorise. This is conjectured to happen due to IR ambiguities in the massless tree-level amplitudes. We present a definition of the massless S-matrix which has all the nice properties of integrable theories, there is no particle production and the S-matrix factorises. As an example, we present in detail the case of the $SU(2)$ principal chiral model (PCM).