The [Formula: see text] transition form factor from space- and time-like experimental data.

Area of Science:

• Nuclear Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The pion transition form factor is crucial for understanding meson properties.
• Previous analyses were limited by model dependence or energy ranges.

Purpose of the Study:

• To analyze the pion transition form factor in both space- and time-like regions.
• To extract precise slope and curvature parameters using new experimental data.
• To investigate the impact on meson mixing and coupling constants.

Main Methods:

• Model-independent analysis using rational approximants.
• Utilizing experimental data from the A2 Collaboration on dielectron invariant mass.
• Extraction of form factor parameters at zero and infinity.

Main Results:

• First-time analysis of the pion transition form factor in both space- and time-like regions.
• Precise determination of slope and curvature parameters and values at zero and infinity.
• Quantified impact on the pi-eta-eta' mixing parameters.

Conclusions:

• The model-independent approach provides robust parameters for the pion transition form factor.
• New results refine understanding of meson mixing and renormalization effects.
• Improved determination of couplings for radiative decays.