Effects of relativity in proton-proton bremsstrahlung

G.H. Martinus, O. Scholten, J.A. Tjon

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Scopus)

Abstract

We investigate the influence of negative-energy states in proton-proton bremsstrahlung in a fully relativistic framework using the T matrix of Fleischer and Tjon. The contribution from negative-energy states in the single-scattering diagrams is shown to be large, indicating that relativistic effects are important. The rescattering contribution compensates some of the effect, which is shown to be a consequence of a low-energy theorem. The net effect of negative-energy states nevertheless is of the order of 20% at higher energies. We investigate retardation effects in the nucleon-nucleon (NN) interaction by means of a one-pion exchange model, which gives effects of the order of 15% at the pion-production threshold. We furthermore modify the NN T matrix tb incorporate some of these effects, and find that on the level of single-scattering contributions they are of the order of 10%. We show predictions at incoming proton energy T-lab=190 MeV, where high accuracy measurements are being done at KVI, and conclude that even at these relatively low energies off-shell effects in the NN interaction and contributions from negative-energy states clearly show up.

Original languageEnglish
Pages (from-to)2945-2962
Number of pages18
JournalPhysical Review C
Volume56
Issue number6
Publication statusPublished - Dec-1997

Keywords

  • NUCLEON-NUCLEON-SCATTERING
  • COMPOSITE SPIN-1/2 SYSTEM
  • BETHE-SALPETER-EQUATION
  • PARTIAL-WAVE ANALYSIS
  • ONE-BOSON-EXCHANGE
  • VECTOR INTERACTIONS
  • PP-BREMSSTRAHLUNG
  • DEUTERON
  • SCALAR
  • PION

Cite this