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arXiv · 2403.11975

Strongly-ordered infrared counterterms from factorisation

Lorenzo Magnea·Calum Milloy·Chiara Signorile-Signorile·Paolo Torrielli
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Abstract

In the context of infrared subtraction algorithms beyond next-to-leading order, it becomes necessary to consider multiple infrared limits of scattering amplitudes, in which several particles become soft or collinear in a strongly-ordered sequence. We study these limits from the point of view of infrared factorisation, and we provide general definitions of strongly-ordered soft and collinear kernels in terms of gauge-invariant operator matrix elements. With these definitions in hand, it is possible to construct local subtraction counterterms for strongly-ordered configurations. Because of their factorised structure, these counterterms cancel infrared poles of real-virtual contributions by construction. We test these ideas at tree level for multiple emissions, and at one loop for single and double emissions, contributing to NNLO and N3LO distributions, respectively.

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Lorenzo Magnea, Calum Milloy, Chiara Signorile-Signorile, Paolo Torrielli. 2024-03-18. Strongly-ordered infrared counterterms from factorisation. https://arxiv.org/abs/2403.11975

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