Electromagnetic form factor of pion in the field theory inspired approach

TL;DR

This paper introduces a new theoretical formula for the pion electromagnetic form factor that incorporates meson loops and rho meson mixing, accurately matching experimental data in both timelike and spacelike regions.

Contribution

It presents a novel, analytically consistent formula for F_pi that accounts for meson interactions and resonance mixing, applicable across different kinematic regions.

Findings

Accurately fits experimental data below 1 GeV from multiple detectors.

Provides a consistent description of F_pi in both timelike and spacelike regions.

Matches NA7 measurements using resonance parameters from timelike analysis.

Abstract

A new formula for the pion form factor F_pi is proposed which takes into account the pseudoscalar meson loops and the mixing among rho(770), rho(1450), and rho(1700). The expression possesses correct analytical properties and can be used in both timelike and spacelike kinematical regions. The comparison is made with the existing experimental data on F_pi collected by the detectors SND, CMD-2, KLOE, and BaBaR restricted to energies below 1 GeV. A good description of all four data sets is obtained. In the spacelike region, upon substituting the resonance parameters found in the timelike one, the formula gives F_pi, in agreement with the measurements of the NA7 Collaboration.