Pion-electroproduction

Threshold pion electroproduction at large momentum transfers

“…As a prominent example, the LET establishes a connection between charged pion electroproduction and the axial form factor of the nucleon. In the real world the pion has a mass, m π /m N ∼ 1/7, and the study of finite pion mass corrections to LET was a topical field in high energy physics in the late sixties and early seventies before the celebrated discovery of Bjorken scaling in deepinelastic scattering and the advent of QCD, see, in particular, the work by Vainshtein and Zakharov [4] and a monograph by Amaldi, Fubini and Furlan [5] that addresses many of these developments.…”

Electroproduction of neutral pions in the Hall A at the Jefferson Laboratory; Electroproduction de pions neutres dans le Hall A au Jefferson Laboratory

“…Moreover, it has the simplest content in terms of constituent quarks, and it has no spin. Thanks to this, the pion electroproduction always had a particular place among all electron-nucleon scattering processes [4].…”

“…Thanks to this, ep → enπ + contains information on the pion form factor, as well as the proton and the neutron form factors. According to [4], the transverse and longitudinal cross sections of the reaction ep → enπ + in the Born approximation (OPEA) is expressed as:…”

“…The authors of [4] even propose to get independent neutron form factor measurements compared to electron neutron scattering on nuclei.…”

“…The first loop is filled with liquid hydrogen (LH 2 ), the second with liquid deuterium (LD 2 ), and the third with gaseous 3 He or 4 He. Each of the cryogenic loops provide its cryogenic fluid to a target ladder, containing several targets stacked vertically, and which can be remotely moved to put in beam the desired target.…”