A comprehensive analysis of differential cross sections and analyzing powers in the proton\u2013deuteron break-up channel at 135 MeV

H Tavakoli-Zaniani,R Ramazani-Sharifabadi,M Mohammadi-Dadkan,N Kalantar-Nayestanaki,M Eslami-Kalantari,E Stephan,H R Amir-Ahmadi,St Kistryn,H Mardanpour,A Ramazani-Moghaddam-Arani,H Witała,A Kozela,J Golak,R Skibiński,M T Bayat,J G Messchendorp,A Deltuva

doi:10.1140/epja/s10050-021-00358-2

Abstract

A selection of measured cross sections and vector analyzing powers, A_{x} and A_{y}, are presented for the vec {p}{d} break-up reaction. The data are taken with a polarized proton beam with a kinetic energy of 135 MeV using the Big Instrument for Nuclear-polarization Analysis (BINA) at KVI, the Netherlands. With this setup, A_{x} is extracted for the first time for a large range of energies as well as polar and azimuthal angles of the two outgoing protons. For most of the configurations, the results at small and large relative azimuthal angles differ in behavior when comparing experimental data with the theoretical calculations. We also performed a more global comparison of our data with theoretical calculations. The cross-section results show huge values of chi ^{2}/d.o.f.. The absolute values of chi ^{2}/d.o.f. for the components of vector analyzing powers, A_{x} and A_{y}, are smaller than the ones for the cross section, partly due to larger uncertainties for these observables. However, also for these observables no satisfactory agreement is found for all angular combinations. This implies that the present models of a three-nucleon force are not able to provide a satisfactory description of experimental data.

Highlights

The nucleon-nucleon (2N) interaction has been studied extensively in the past using proton–proton and proton–neutron scattering data, the role of higher-order forces, such as the three-nucleon force (3NF) remains mysterious
We are interested in the transition of the initial state to a final state via the intermediate state, The pd break-up reaction was studied using a polarized proton beam of 135 MeV impinging on a liquid deuterium target which was located at the center of BINA (Big Instrument for Nuclear-polarization Analysis)
To study the three nucleon systems, the reaction d( p, pp)n was studied at KVI using a polarized proton beam

Summary

Introduction

The nucleon-nucleon (2N) interaction has been studied extensively in the past using proton–proton and proton–neutron scattering data, the role of higher-order forces, such as the three-nucleon force (3NF) remains mysterious. The need for an additional three-nucleon potential became evident when comparing three-body scattering observables [1,2] and binding energies of light nuclei [3] with state-of-the-art calculations [1,2,3]. The step would be to significantly extend the world database in the three-nucleon scattering system as a benchmark to eventually have a better understanding of the structure of the three-nucleon interaction. For almost all observables in nucleon–deuteron elastic scattering, the calculations which only include two nucleon forces (2NFs) fail to a large extent to describe the data, in particular at energies above 60 MeV 58 Page 2 of 9. In addition to the elastic channel, the deuteron break-up reaction offers a rich spectrum of kinematical configurations and as such provides a good testing ground for understanding the structure of the nuclear force [7]

Methods

Findings

Discussion

Conclusion