QCD Predictions for Meson Electromagnetic Form Factors at High Momenta: Testing Factorization in Exclusive Processes.

Area of Science:

• High Energy Physics
• Quantum Chromodynamics (QCD)
• Hadron Physics

Background:

• Electromagnetic form factors describe how hadrons interact with photons.
• Previous calculations were limited in their momentum transfer range.
• Understanding these form factors is key to probing the structure of matter at high energies.

Purpose of the Study:

• To perform the first lattice QCD computation of pion and kaon electromagnetic form factors at large momentum transfer (Q^2).
• To provide ab initio QCD benchmarks for experimental results at Jefferson Lab (JLab) and future colliders.
• To test the QCD collinear factorization framework at next-to-next-to-leading order.

Main Methods:

• Utilized lattice QCD with physical meson masses on two fine lattices.
• Calculated form factors up to Q^2 = 10 GeV^2 for pions and 28 GeV^2 for kaons.
• Employed the QCD collinear factorization framework at N3LO (next-to-next-to-leading order).

Main Results:

• Achieved good agreement with JLab experimental data for Q^2 ≲ 4 GeV^2.
• Provided ab initio QCD benchmarks for Q^2 ≳ 4 GeV^2, valuable for future experiments.
• Demonstrated the universality of nonperturbative meson distribution amplitudes within uncertainties.

Conclusions:

• Lattice QCD calculations can accurately describe pion and kaon electromagnetic form factors at large momentum transfer.
• The study validates the QCD collinear factorization framework and provides essential nonperturbative inputs.
• Results pave the way for precise theoretical predictions and interpretations of future experimental data.