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  • Letter
  • Open Access

Catani’s generalization of collinear factorization breaking

Leandro Cieri*, Prasanna K. Dhani†, and Germán Rodrigo‡

  • *Contact author: lcieri@ific.uv.es
  • †Contact author: dhani@ific.uv.es; prasanna.dhani@physik.uzh.ch
  • ‡Contact author: german.rodrigo@csic.es
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Phys. Rev. D 113, L031506 – Published 26 February, 2026

DOI: https://doi.org/10.1103/jfy8-xqsn

Abstract

We consider the most general form of soft and collinear factorization for hard-scattering amplitudes to all orders in perturbative quantum chromodynamics. Specifically, we present the generalization of collinear factorization to configurations with several collinear directions, where the most singular behavior is encoded by generalized collinear splitting amplitudes that manifestly embed the breaking of strict collinear factorization in spacelike collinear configurations. We also extend the analysis to the simultaneous soft-collinear factorization with multiple collinear directions where naive multiplicative factorization does not hold. As an illustrative example of factorization breaking, we present explicit results at the one-loop level in the soft-collinear limit.

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Outline

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Phys. Rev. D 113, L031506– Published 26 February, 2026
  • Received 26 February 2024
  • Revised 16 September 2025
  • Accepted 6 February 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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