Pion and Kaon Distribution Amplitudes from Lattice QCD

Area of Science:

• High Energy Physics
• Quantum Chromodynamics
• Hadron Physics

Background:

• Light-cone distribution amplitudes (DAs) are crucial for understanding hadron structure.
• Previous calculations often relied on approximations or lacked precision.

Purpose of the Study:

• To perform a state-of-the-art lattice QCD calculation of pion and kaon light-cone DAs.
• To investigate deviations from asymptotic forms and probe SU(3) flavor symmetry breaking.

Main Methods:

• Utilized large-momentum effective theory (LaMET) on a lattice.
• Employed three lattice spacings and physical meson masses.
• Performed nonperturbative renormalization and continuum/infinite momentum extrapolations.

Main Results:

• Pion and kaon DAs show significant deviations from the asymptotic form.
• A substantial SU(3) flavor breaking effect was found in the kaon DA.

Conclusions:

• The calculated pion and kaon DAs provide crucial insights into hadron structure beyond simple models.
• The findings highlight the importance of nonperturbative methods in QCD and the role of flavor symmetry breaking.