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arXiv · 2609.08761

Theory updates for parton distributions in Hessian formalism

Petja Paakkinen·Hannu Paukkunen·Sami Yrjänheikki
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Abstract

We present a new extension to the toolbox of parton-distribution reweighting methods, which enables a general user to study the impact of an updated theory prediction on the results of a pre-existing parton-distribution global analysis. This new method is a combination of the well-known reweighting method with a new deweighting variant where a dataset is removed from the original analysis in an approximate way. Specific use cases of this method could include e.g. testing the impact of updating the treatment of an observable from N$^n$LO to N$^{n+1}$LO precision in the global analysis, or including previously ignored electroweak, mass, resummation, or higher-twist effects, or even testing the impact of some beyond-standard-model physics. We discuss the implementation of this method in the Hessian formalism, and show its use in a single case study, where we update the treatment of dimuon production in neutrino-induced DIS with the novel semi-inclusive DIS approach.

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Petja Paakkinen, Hannu Paukkunen, Sami Yrjänheikki. 2026-09-08. Theory updates for parton distributions in Hessian formalism. https://arxiv.org/abs/2609.08761

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