Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor

TL;DR

This paper presents a detailed extraction of the charged pion form factor from Jefferson Lab data in the Q^2 range 0.60 to 2.45 GeV^2, highlighting model dependencies and comparing results with theoretical models to understand hadronic structure.

Contribution

It provides a comprehensive methodology for extracting Fpi from electroproduction data, emphasizing the dominant uncertainties and comparing experimental results with various theoretical calculations.

Findings

Fpi values are below the monopole model above Q^2=1.5 GeV^2

Extraction method details and uncertainty analysis are provided

Comparison with theoretical models aids understanding of soft vs. hard contributions

Abstract

The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime.