272 research outputs found
Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering
High precision vector and tensor analyzing powers of elastic deuteron-proton
d+p scattering have been measured at intermediate energies to investigate
effects of three-nucleon forces (3NF). Angular distribution in the range of
70-120 degree in the center-of mass frame for incident-deuteron energies of 130
and 180 MeV were obtained using the RIKEN facility. The beam polarization was
unambiguously determined by measuring the 12C(d,alpha)10B(2+) reaction at 0
degree. Results of the measurements are compared with state-of-the-art
three-nucleon calculations. The present modeling of nucleon-nucleon forces and
its extension to the three-nucleon system is not sufficient to describe the
high precision data consistently and requires, therefore, further
investigation
Measurements of scattering observables for the break-up reaction
High-precision measurements of the scattering observables such as cross
sections and analyzing powers for the proton-deuteron elastic and break-up
reactions have been performed at KVI in the last two decades and elsewhere to
investigate various aspects of the three-nucleon force (3NF) effects
simultaneously. In 2006 an experiment was performed to study these effects in
break-up reaction at 135 MeV with the detection system, Big
Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the
entire kinematical phase space of the break-up reaction. The results are
interpreted with the help of state-of-the-art Faddeev calculations and are
partly presented in this contribution.Comment: Proceedings of 19th International IUPAP Conference on Few-Body
Problems in Physics, Bonn University, 31.08 - 05.09.2009, Bonn, GERMAN
Systematic investigation of the elastic proton-deuteron differential cross section at intermediate energies
To investigate the importance of three-nucleon forces (3NF) systematically
over a broad range of intermediate energies, the differential cross sections of
elastic proton-deuteron scattering have been measured at proton bombarding
energies of 108, 120, 135, 150, 170 and 190 MeV at center-of-mass angles
between and . Comparisons with Faddeev calculations show
unambiguously the shortcomings of calculations employing only two-body forces
and the necessity of including 3NF. They also show the limitations of the
latest few-nucleon calculations at backward angles, especially at higher beam
energies. Some of these discrepancies could be partially due to relativistic
effects. Data at lowest energy are also compared with a recent calculation
based on \chipt
Proton-deuteron radiative capture cross sections at intermediate energies
Differential cross sections of the reaction have been
measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were
obtained with a coincidence setup measuring both the outgoing He and the
photon. The data are compared with modern calculations including all possible
meson-exchange currents and two- and three- nucleon forces in the potential.
The data clearly show a preference for one of the models, although the shape of
the angular distribution cannot be reproduced by any of the presented models.Comment: 6 pages, 6 figures, accepted for publication in EPJ
Spin observables in deuteron-proton radiative capture at intermediate energies
A radiative deuteron-proton capture experiment was carried out at KVI using
polarized-deuteron beams at incident energies of 55, 66.5, and 90 MeV/nucleon.
Vector and tensor-analyzing powers were obtained for a large angular range. The
results are interpreted with the help of Faddeev calculations, which are based
on modern two- and three-nucleon potentials. Our data are described well by the
calculations, and disagree significantly with the observed tensor anomaly at
RCNP.Comment: 10 pages, 4 figures, submitted to PL
Comprehensive measurements of cross sections and spin observables of the three-body break-up channel in deuteron-deuteron scattering at 65 MeV/nucleon
Detailed measurements of five-fold differential cross sections and a rich set
of vector and tensor analyzing powers of the 2H(d; dp)n break-up process using
polarized deuteron-beam energy of 65 MeV/nucleon with a liquid-deuterium target
are presented. The experiment was conducted at the AGOR facility at KVI using
the BINA 4Pi-detection system. We discuss the analysis procedure including a
thorough study of the systematic uncertainties. The results can be used to
examine upcoming state-of-the-art calculations in the four-nucleon scattering
domain, and will, thereby, provide further insights into the dynamics of three-
and four-nucleon forces in few-nucleon systems. The results of coplanar
configurations are compared with the results of recent theoretical calculations
based on the Single-Scattering Approximation (SSA). Through these comparisons,
the validity of SSA approximation is investigated in the Quasi-Free (QF)
region.Comment: 33 pages, 30 figure
Analyzing powers at low nucleon–nucleon relative energies in proton–deuteron breakup reaction
Vector analyzing powers for the reaction have been measured at KVI for different kinematical configurations using a polarized proton beam with an energy of 190 MeV. We compared our data with different theoretical calculations at extremely low relative energies of the proton–proton and proton–neutron systems in the final state. For the proton–neutron case, we used the information of the two detected protons in the final state in which one of them scattered to an angle smaller than 40 and the other one to an angle larger than 100 in the laboratory frame. We extrapolated our measurements towards a kinematical configuration to a vanishing relative energy. Our results show that none of the theoretical models presented here is able to reproduce experimental data for the proton–proton case at very low relative energies. For the proton–neutron case, we were not able to provide a reliable extrapolation to small relative energies of less than 1 MeV. Present results are the basis for future investigations of spin-isospin dependencies in the nuclear many-body force
Signatures of three-nucleon interactions in few-nucleon systems
Recent experimental results in three-body systems have unambiguously shown
that calculations based only on nucleon-nucleon forces fail to accurately
describe many experimental observables and one needs to include effects which
are beyond the realm of the two-body potentials. This conclusion owes its
significance to the fact that experiments and calculations can both be
performed with a high accuracy. In this review, both theoretical and
experimental achievements of the past decade will be underlined. Selected
results will be presented. The discussion on the effects of the three-nucleon
forces is, however, limited to the hadronic sector. It will be shown that
despite the major successes in describing these seemingly simple systems, there
are still clear discrepancies between data and the state-of-the-art
calculations.Comment: accepted for publication in Rep. Prog. Phy
Elastic proton-deuteron scattering at intermediate energies
Observables in elastic proton-deuteron scattering are sensitive probes of the
nucleon-nucleon interaction and three-nucleon force effects. The present
experimental data base for this reaction is large, but contains a large
discrepancy between data sets for the differential cross section taken at 135
MeV/nucleon by two experimental research groups. This paper reviews the
background of this problem and presents new data taken at KVI. Differential
cross sections and analyzing powers for the and
reactions at 135 MeV/nucleon and 65 MeV/nucleon,
respectively, have been measured. The data differ significantly from previous
measurements and consistently follow the energy dependence as expected from an
interpolation of published data taken over a large range at intermediate
energies.Comment: 5 pages, 4 figures, submitted to PR
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