Charged pion form factor between Q[superscript 2] = 0 . 60 and 2 . 45 GeV[superscript 2]. II. Determination of, and results for, the pion form factor

Abstract

The charged pion form factor, F[subscript pi](Q[superscript 2]), is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction of F[subscript pi] from data requires a model of the [superscript 1]H(e, e'[pi][superscript +])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 F[subscript pi] are presented for Q[superscript 2] = 0.60–2.45 GeV[superscript 2]. Above Q[superscript 2] = 1.5 GeV[superscript 2],the F[subscript pi] values are systematically below the monopole parametrization that describes the low Q[superscript 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[superscript 2] regime.