Discussions of Ambiguities on Current Operators in Exclusive (e,e′p) Reactions for Intermediate Electron Energy

抄録

Possible ambiguities in the theoretical interpretation of exclusive (e,e′p) reactions are discussed on the basis of realistic model calculations. Gauge ambiguity, medium effects, and contribution of the Δ current are evaluated in distorted wave Born approximation (DWBA) where the four momentum transfer square |q_μ|² is less than 0.5 (GeV/c)². The gauge ambiguity effects are shown to be about 10% in the small missing momentum region and about 20% maximally in the high missing momentum region. Medium effects of about 6–10% appear mainly in the small missing momentum region. The Δ-resonance current influences the high missing momentum region by about 10% maximally.