Vector and tensor analyzing powers in deuteron-proton breakup

Abstract

Vector and tensor analyzing powers of the breakup reaction at 130 and 100 MeV deuteron beam energies have been measured at KVI Groningen with the use of the detection systems covering large fractions of the phase space. The high precision data are compared to the theoretical predictions based on various approaches to describe the three nucleon (3N) system dynamics. Theoretical predictions describe very well the vector analyzing power data, with no need to include any three-nucleon force effects for these observables. The tensor analyzing powers can be also very well reproduced by calculations in most of the studied region, but locally certain discrepancies are observed. At 130 MeV for Axy such discrepancies usually appear, or are enhanced, when model 3N forces (3NFs), TM99 or Urbana IX, are included. Problems of all theoretical approaches with describing Axx and Ayy are limited to very small regions of the phase space, usually characterized with the lowest relative energies of the two protons. Predicted effects of 3NFs are much lower at 100 MeV, therefore at this energy equally good consistency between the data and the calculations is obtained with or without 3NFs.