Probing Proton Structure at the Large Hadron electron Collider

Abstract

For the foreseeable future, the exploration of the high-energy frontier will be the domain of the Large Hadron Collider (LHC). Of particular significance will be its high-luminosity upgrade (HL-LHC), which will operate until the mid-2030s. In this endeavour, for the full exploitation of the HL-LHC physics potential an improved understanding of the parton distribution functions (PDFs) of the proton is critical. The HL-LHC program would be uniquely complemented by the proposed Large Hadron electron Collider (LHeC), a high-energy lepton-proton and lepton-nucleus collider based at CERN. In this work, we build on our recent PDF projections for the HL-LHC to assess the constraining power of the LHeC measurements of inclusive and heavy quark structure functions. We find that the impact of the LHeC would be significant, reducing PDF uncertainties by up to an order of magnitude in comparison to state-of-the-art global fits. In comparison to the HL-LHC projections, the PDF constraints from the LHeC are in general more significant for small and intermediate values of the momentum fraction x. At higher values of x, the impact of the LHeC and HL-LHC data is expected to be of a comparable size, with the HL-LHC constraints being more competitive in some cases, and the LHeC ones in others. Our results illustrate the encouraging complementarity of the HL-LHC and the LHeC in terms of charting the quark and gluon structure of the proton.

arXiv comment27 pages, 13 figures. PDF projections for the LHeC and the HL-LHC available from Zenodo at https://zenodo.org/record/3250580. v2: extended discussion on methodological choices. v3 further cross-checks added

References in corpus (32)

• Parton distributions for the LHC Run II
• LHAPDF6: parton density access in the LHC precision era
• Parton distributions from high-precision collider data
• PDF4LHC recommendations for LHC Run II
• New parton distribution functions from a global analysis of quantum chromodynamics
• Parton distributions in the LHC era: MMHT 2014 PDFs
• A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector
• Parton Distribution Functions, ${\alpha }_s$ and Heavy-Quark Masses for LHC Run II
• APFEL: A PDF Evolution Library with QED corrections
• Heavy quarks in deep-inelastic scattering
• Parton distributions and lattice QCD calculations: a community white paper
• The Structure of the Proton in the LHC Precision Era
• Parton distributions with small-x resummation: evidence for BFKL dynamics in HERA data
• The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II
• A meta-analysis of parton distribution functions
• A Critical Appraisal and Evaluation of Modern PDFs
• Parton Distribution Benchmarking with LHC Data
• Study of Monte Carlo approach to experimental uncertainty propagation with MSTW 2008 PDFs
• PDF reweighting in the Hessian matrix approach
• An Unbiased Hessian Representation for Monte Carlo PDFs
• Fitting Parton Distribution Data with Multiplicative Normalization Uncertainties
• Impact of heavy-flavour production cross sections measured by the LHCb experiment on parton distribution functions at low x
• Precision determination of the small-$x$ gluon from charm production at LHCb
• NNLO QCD corrections to jet production in deep inelastic scattering
• Can New Physics hide inside the proton?
• Updating and Optimizing Error PDFs in the Hessian Approach
• Towards Ultimate Parton Distributions at the High-Luminosity LHC
• N3LO Corrections to Jet Production in Deep Inelastic Scattering using the Projection-to-Born Method
• Non-quadratic improved Hessian PDF reweighting and application to CMS dijet measurements at 5.02 TeV
• The exclusive $J/\psi$ process at the LHC tamed to probe the low $x$ gluon
• Jet production in charged-current deep-inelastic scattering to third order in QCD
• On the Consistent Use of Scale Variations in PDF Fits and Predictions

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• Parton Distributions in Nucleons and Nuclei
• SMEFT analysis of vector boson scattering and diboson data from the LHC Run II
• Breaking up the Proton: An Affair with Dark Forces
• Simultaneous CTEQ-TEA extraction of PDFs and SMEFT parameters from jet and $t\bar{t}$ data
• An Evaluation of The Proton Structure Functions $F_2$ and $F_L$ at Small $x$
• Machine learning of log-likelihood functions in global analysis of parton distributions
• Yadism: Yet Another Deep-Inelastic Scattering Module
• Transverse momentum dependent of charged pion, kaon and proton/antiproton fragmentation functions from $e^{+}{e}^{-}$ annihilation process
• A data-based parametrization of parton distribution functions
• Differential distributions for Single Top Quark Production at the LHeC
• Importance of the heavy-quarks longitudinal structure function measurements at future circular collider energies
• Collinear approach for top quark production at ep colliders
• Parton distribution functions and strong coupling constant: MSHT