Deep-Inelastic-scattering and Vector-boson-fusion Advances

The Large Hadron Collider (LHC) probes interactions among particles with unprecedented precision.

The determination of the Higgs boson properties is a central pillar of the LHC physics program and of the current LHC run.This demands for accurate theoretical predictions, which usually hinge on Monte Carlo event generators.

State-of-the-art predictions are given by next-to-leading-order (NLO) calculations in QCD matched to leading-logarithmic (LL) parton shower (PS).

Next-to-NLO (NNLO) matching, necessary to advance the accuracy of theoretical predictions, is limited to specific processes, like the hadro-production of heavy systems in the final state.Vector Boson Fusion (VBF) is the preferred channel for the determination of the Higgs to muon couplings and for Higgs to invisible searches.

This project's aim is to pioneer NNLO matching techniques for processes characterised by the t-channel exchange of a colourless boson, such as VBF and Vector Boson Scattering (VBS), and to develop the first NNLO+PS generator for Higgs boson production in VBF.Given the close relationship between higher-order corrections in VBF, VBS, and Deep Inelastic Scattering (DIS), the initial focus will be the formulation of a NNLO+PS matching scheme for DIS.

This matching will preserve the logarithmic accuracy of both the new next-to LL (NLL) showers, and the standard LL ones. Additionally, to achieve this task, novel resummed predictions for DIS will be produced.

Reaching NNLO+NLL accuracy within a comprehensive PS simulation is a groundbreaking endeavour.These outcomes will be vital for precise studies of the Higgs sector in the current and future LHC runs, and for high-precision investigations at future DIS-type facilities like the Electron-Ion Collider.

Furthermore, this project will lay the foundations for a more widely applicable NNLO+PS matching approach with superior logarithmic accuracy, which can be extended to a broader range of collider processes involving QCD jets.