Total Hadronic Cross Section of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>Rays in Hydrogen in the Energy Range 0.265-4.215 GeV

Abstract

The total cross section of $\ensuremath{\gamma}$ rays in hydrogen resulting in hadron production, ${\ensuremath{\sigma}}_{T}$, has been measured over the energy range 265-4215 MeV. A tagging system with narrow energy bins was employed. Structure in the resonance region followed by a steady fall with energy has been observed and the results are analyzed. The forward amplitude of $\ensuremath{\gamma}$-proton scattering is evaluated, and its behavior in the Argand diagram studied as a function of energy. The relationships of the measurements to Regge-pole theory and the vector-dominance model are detailed.