Polarised cross sections for loop-induced processes with SHERPA+RECOLA
Abstract
Studying vector boson polarisation has become an integral part of the LHC physics programme in recent years, as it provides an independent test of the electroweak symmetry-breaking mechanism and the gauge sector of the electroweak Standard Model. These measurements require polarised templates from parton-shower Monte Carlo simulations. Their accuracy does not yet meet the precision requirements of upcoming measurements, leading to significant modelling uncertainties in experimental analyses that will constrain the LHC's polarisation sensitivity at latest in the HL-LHC phase. Polarised loop-induced processes have so far not been included in most parton-shower event generators, despite contributing significantly to processes of interest. In this work, we present the extension of the polarisation framework in the Monte Carlo event generator SHERPA to polarised loop-induced processes at fixed LO and LO matched to parton shower. In addition to a description of the methodology based on polarised amplitudes from the RECOLA matrix element generator, we discuss polarisation effects in relevant inclusive, loop-induced processes and their jet-associated counterparts, several of them for the first time. Both the influence of different polarisation definitions and of QCD and QED resummation effects are investigated.
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BibTeX
@misc{hoppe2026polarised,
title = {{Polarised cross sections for loop-induced processes with SHERPA+RECOLA}},
author = {Mareen Hoppe and Marek Schönherr and Frank Siegert},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.06698},
eprint = {2610.06698},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.06698},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Polarised cross sections for loop-induced processes with SHERPA+RECOLA
AU - Mareen Hoppe
AU - Marek Schönherr
AU - Frank Siegert
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.06698
UR - https://arxiv.org/abs/2610.06698
AB - Studying vector boson polarisation has become an integral part of the LHC physics programme in recent years, as it provides an independent test of the electroweak symmetry-breaking mechanism and the gauge sector of the electroweak Standard Model. These measurements require polarised templates from parton-shower Monte Carlo simulations. Their accuracy does not yet meet the precision requirements of upcoming measurements, leading to significant modelling uncertainties in experimental analyses that will constrain the LHC's polarisation sensitivity at latest in the HL-LHC phase. Polarised loop-induced processes have so far not been included in most parton-shower event generators, despite contributing significantly to processes of interest. In this work, we present the extension of the polarisation framework in the Monte Carlo event generator SHERPA to polarised loop-induced processes at fixed LO and LO matched to parton shower. In addition to a description of the methodology based on polarised amplitudes from the RECOLA matrix element generator, we discuss polarisation effects in relevant inclusive, loop-induced processes and their jet-associated counterparts, several of them for the first time. Both the influence of different polarisation definitions and of QCD and QED resummation effects are investigated.
ER -