2005/04/30 by L. P. Kaptari, B. Kämpfer, B. Kampfer
Physics and Astronomy · #Atomic and Molecular Physics #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.1016/j.nuclphysa.2005.10.007
published as Nucl.Phys.A764:338-370,2006
arxiv created 2005/10/14 · openalex publication_date 2005/11/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Invariant mass spectra of di-electrons stemming from bremsstrahlung processes are calculated in a covariant diagrammatical approach for the exclusive reaction D p → p\rm sp n p e+ e- with detection of a forward spectator proton, psp. We employ an effective nucleon-meson theory for parameterizing the sub-reaction n p → n p e+ e- and, within the Bethe-Salpeter formalism, derive a factorization of the cross section in the form dσ_D p → p\rm sp n p e+ e-/dM= dσn p → n p e+ e-/dM × kinematical factor related solely to the deuteron (M is the e+ e- invariant mass). The effective nucleon-meson interactions, including the exchange mesons π, σ, ωand ρas well as excitation and radiative decay of Δ(1232), have been adjusted to the process pp → pp e+ e- at energies below the vector meson production threshold. At higher energies, contributions from ωand ρmeson excitations are analyzed in both, NN and Dp collisions. A relation to two-step models is discussed. Subthreshold di-electron production in Dp collisions at low spectator momenta is investigated as well. Calculations have been performed for kinematical conditions envisaged for forthcoming experiments at HADES.