Towards ultimate parton distributions at the high-luminosity LHC

Area of Science:

• High Energy Physics
• Quantum Chromodynamics
• Particle Physics

Background:

• The Large Hadron Collider (LHC) has provided extensive data on proton structure.
• Parton distribution functions (PDFs) are crucial for interpreting LHC measurements.
• Current PDF analyses incorporate diverse LHC data, including jet and boson production.

Purpose of the Study:

• To evaluate the maximum impact of LHC data on PDFs, especially after the High-Luminosity (HL) phase.
• To quantify the precision of PDFs obtainable from future HL-LHC datasets.
• To assess the potential reduction in PDF uncertainties.

Main Methods:

• Generation of HL-LHC pseudo-data simulating future experimental conditions.
• Application of the Hessian profiling method to constrain the PDF4LHC15 set.
• Analysis of projected statistical and systematic uncertainties from HL-LHC measurements.

Main Results:

• HL-LHC data are projected to reduce PDF uncertainties by a factor of 2 to 4 compared to current fits.
• Uncertainties for key observables, like the Higgs boson transverse momentum, could reach few-percent levels.
• Significant improvements in PDF precision are expected from hadron collider data alone.

Conclusions:

• The HL-LHC will dramatically enhance the precision of parton distribution functions.
• These improved PDFs will lead to more precise predictions for fundamental physics processes.
• Continued PDF-sensitive measurements at the LHC are strongly motivated.