110 citations · 485 across the 58 of their papers we have counts for
14 papers · 1 filter
Alpha-Alpha scattering, chiral symmetry and 8Be lifetime
E. Ruiz Arriola
Alpha-alpha scattering is discussed in terms of a chiral two pion exchange potential which turns out to be attractive and singular at the origin, hence demanding renormalization. W…
Coulomb-scattering and eta - eta-prime mixing angle
F. Kleefeld
The fascinating physics underlying eta and eta-prime mesons can be studied theoretically and experimentally in various contexts. In this presentation we want to turn our attention…
Does it make any sense to talk about a Delta-isobar?
F. Kleefeld
It is shortly investigated, on what basis an experimentally observed resonance like the Delta(1232)-isobar can be embedded into the framework of Quantum Theory (QT), i.e. Quantum F…
ISI and FSI in NN-->NNX reactions
F. Kleefeld
The present status of the theoretical description of Initial (ISI) and Final State Interactions (FSI) in nucleon induced exclusive meson production processes close to threshold is…
Model-independent definition and determination of electromagnetic formfactors and multipole moments
F. Kleefeld
A theoretical method for the systematic definition and determination of Cartesian and spherical electromagnetic (onshell) formfactors and multipole moments for particles or composi…
ABSSM - a new field-theoretic method of describing scattering/production processes of composite particles by asymptotic in-/outgoing Bethe-Salpeter states
F. Kleefeld
A new relativistic field-theoretic formalism called "Asymptotic Bethe-Salpeter State Method" (ABSSM) is presented, which allows to calculate both electromagnetic formfactors and ha…
ISI/FSI in Threshold Meson Production - Onshell Approach and Coulomb Problem
F. Kleefeld
The onshell description of Initial- and Final-State-Interactions (ISI and FSI) of threshold meson production reactions is reviewed. Existing onshell models and their offshell exten…
Threshold Behaviour of Meson-Nucleon-(1535) Vertexfunctions and Determination of the (1535) Mixing Angle
F. Kleefeld
A new method for the determination of the spin-1/2-3/2-mixing angle and the range parameter of the quarkmodel wavefunction of the resonance is presented. The metho…
Consistent effective description of nucleonic resonances in an unitary relativistic field-theoretic way
F. Kleefeld
High energy strong interaction physics is successfully described by the local renormalizable gauge theory called Quantum-Chromo-Dynamics (QCD) with quarks and gluons as ``elementar…
Protoninduced Pion-, Eta- and Kaon-Production at Threshold
F. Kleefeld, M. Dillig
We present some details of our recent theoretical investigations on the total cross section of the reactions , and at threshold. Applying s…
Proton induced production and the content of the proton
Frieder Kleefeld, Fernando Pilotto, Manfred Dillig
We investigate the exclusive proton-induced production near the kaon threshold. Compared are two models: a meson-exchange model, which includes , ρKK^\ast$ exch…
Bethe-Salpeter-Approach to Relativistic Two-Fermion-Systems with a Separable Nonstatic Interaction
Frieder Kleefeld, Manfred Dillig
To study the characteristic features of relativistic bound systems, the Bethe-Salpeter equation (BSE) for two equal mass spin 1/2 particles (like the deuteron) is solved in the cm-…
Consistent effective field-theoretic treatment of resonances with non zero width
F. Kleefeld
A systematic field theoretic formalism for treating Fermionic resonances with non zero width is given. The implication of unitarity to coupling constants of non local interactions…
Reinvestigation of and at threshold
Frieder Kleefeld, Manfred Dillig
and were considered close to threshold. The pion production was found not only to be dominated by impulse approximation (IA) and rescattering contribution…