Handling the handbag diagram in Compton scattering on the proton
2004; American Institute of Physics; Volume: 69; Issue: 5 Linguagem: Inglês
10.1103/physrevc.69.052201
ISSN1538-4497
Autores Tópico(s)High-Energy Particle Collisions Research
ResumoPoincar\'e invariance, gauge invariance, conservation of parity, and time reversal invariance are respected in an impulse approximation evaluation of the handbag diagram. Proton wave functions, previously constrained by comparison with measured form factors, that incorporate the influence of quark transverse and orbital angular momentum (and the corresponding violation of proton helicity conservation) are used. Computed cross sections are found to be in reasonably good agreement with early measurements. The helicity correlation between the incident photon and outgoing proton, ${K}_{LL}$, is both large and positive at back angles. For photon laboratory energies of $\ensuremath{\leqslant}6\phantom{\rule{0.3em}{0ex}}\text{GeV}$, we find that ${K}_{LL}\ensuremath{\ne}{A}_{LL}$, and ${D}_{LL}\ensuremath{\ne}1$.
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