Charged pion form factor between Q[superscript 2] = 0.60 and 2.45 GeV[superscript 2]. I. Measurements of the cross section for the [superscript 1]H(e, e'[pi][superscript +])n reaction

Abstract

Cross sections for the reaction [superscript 1]H(e, e'[pi][superscript +])n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q[superscript 2] = 0.60 to 2.45 GeV[superscript 2] at an invariant mass of the virtual photon-nucleon system of W = 1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions [sigma][subscript L], [sigma][subscript T], [sigma][subscript LT], and [sigma][subscript TT]. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q[superscript 2] are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction [superscript 1]H(e, e'[pi][superscript +])n.