F. Coester

Charge Form-Factors of Quark Model Pions

We demonstrate that Poincare invariant quark models of the pion can give charge form factors in agreement with all available data. The quark-antiquark model wave functions are spin-zero eigenfunctions of the four-momentum. The relativistic features of the model are essential for the result. The confinement scale is much smaller than the charge radius.

Relativistic quantum dynamics of many-body systems.

Relativistic quantum dynamics requires a unitary representation of the Poincare group on the Hilbert space of states. The dynamics of many-body systems must satisfy cluster separability requirements. In this paper we formulate an abstract framework of four dimensional Euclidean Green functions that can be used to construct relativistic quantum dynamics of N-particle systems consistent with these requirements. This approach should be useful in bridging the gap between few-body dynamics based on phenomenological mass operators and on quantum field theory.

Vacuum structures in Hamiltonian light-front dynamics

Hamiltonian light-front dynamics of quantum fields may provide a useful approach to systematic nonperturbative approximations to quantum field theories. We investigate inequivalent Hilbert-space representations of the light-front field algebra in which the stability group of the light front is implemented by unitary transformations. The Hilbert space representation of states is generated by the operator algebra from the vacuum state. There is a large class of vacuum states besides the Fock vacuum which meet all the invariance requirements. The light-front Hamiltonian must annihilate the vacuum and have a positive spectrum. We exhibit relations of the Hamiltonian to the nontrivial vacuum structure.

Deep‐inelastic lepton scattering by nuclei: The pion‐exchange model

Data from deep inelastic lepton scattering, in particular, the EMC Effect, is analyzed in terms of conventional nuclear theory. A long ranged one‐pion‐exchangeepotential tail, a two‐pion‐exchange intermediate range attraction, and a short range strong phenomenological potential yield a consistent description of the deep inelastic scattering data.