14 research outputs found
Analyzing powers at low nucleonânucleon relative energies in protonâdeuteron 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 protonâproton and protonâneutron systems in the final state. For the protonâneutron 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 protonâproton case at very low relative energies. For the protonâneutron 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
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
Thermodynamic properties of and Nuclei using modified Ginzburg-Landau theory
In this paper, formulation of Modified Ginsberg – Landau theory of second grade phase transitions has been expressed. Using this theory, termodynamic properties, such as heat capacity, energy, entropy and order parameters ofandnuclei has been investigated. In the heat capacity curve, calculated according to tempreture, a smooth peak is observed which is assumed to be a signature of transition from the paired phase to the normal phase of the nuclei. The same pattern is also observed in the experimental data of the heat capacity of the studied nuclei. Calculations of this model shows that, by increasing tempreture, expectation value of the order parameter tends to zero with smoother slip, comparing with Ginsberg – Landau theory. This indicates that the pairing effect exists between nucleons even at high temperatures. The experimental data obtained confirms the results of the model qualitatively
Three-Nucleon Force Studies in Proton-Deuteron Break-Up Reaction with BINA at 190 MeV
The present knowledge of nuclear forces is not sufficient to describe all experimental data for systems which consist of more than two nucleons. Recent three-nucleon scattering experiments have shown that the theoretical models based solely on nucleon-nucleon potentials fail to describe most of the experimental results. In this paper, we present data of the (formula presented) break-up reaction that were obtained using a 190 MeV polarized-proton beam impinging on a liquid deuterium target. The experiment was performed by exploiting BINA (Big Instrument for Nuclear-polarization Analysis), a detector system with a large angular acceptance and a high energy resolution.</p
Three-nucleon forces and their importance in three-nucleon systems and heavier nuclei
In the past two decades, several laboratories have produced a large amount of data for cross sections, analyzing powers, and other spin observables from various reactions in the three-nucleon system. The experimental results are moderately described by only using the two-nucleon potentials in Faddeev-type calculations. The remaining discrepancies should, in principle, and aside from Coulomb and relativistic effects, be removed once the effects of three-nucleon forces are implemented. High precision data on elastic and break-up reactions show, however, that even after the inclusion of these effects, the picture is not complete yet and some ingredients are still missing in the calculations. With the advent of new frameworks within which two and three-nucleon forces can be properly implemented in the calculation of observables in heavy nuclei, it is essential that these forces are better understood
Three-Nucleon Force Studies in Proton-Deuteron Break-Up Reaction with BINA at 190 MeV
The present knowledge of nuclear forces is not sufficient to describe all experimental data for systems which consist of more than two nucleons. Recent three-nucleon scattering experiments have shown that the theoretical models based solely on nucleon-nucleon potentials fail to describe most of the experimental results. In this paper, we present data of the (formula presented) break-up reaction that were obtained using a 190 MeV polarized-proton beam impinging on a liquid deuterium target. The experiment was performed by exploiting BINA (Big Instrument for Nuclear-polarization Analysis), a detector system with a large angular acceptance and a high energy resolution
Calculation of A (x) for the Proton-Deuteron Breakup Reaction at 135 MeV
<p>Observables in proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects (3NF). Several facilities in the world, including Kernfysisch Versneller Instituut (KVI), allow a detailed study a few-nucleon interaction below the pion-production threshold exploiting polarized proton and deuteron beams. In this contribution we explored 3NF effects in the break-up scattering process by performing a measurement of differential cross section and the analyzing power, especially the x component of the analyzing power, using a 135 MeV polarized-proton beam impinging on a liquid-deuteron target. The proton-deuteron breakup reaction leads to a final state with three free particles and a rich phase space that allows us to study observables for continuous set of kinematical configurations of the outgoing nucleons. The results are interpreted with the help of state-of-the-art Faddeev calculations.</p>
Analyzing powers at low nucleonânucleon relative energies in protonâdeuteron breakup reaction
Vector analyzing powers for the d(pâ , pp) n 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 protonâproton and protonâneutron systems in the final state. For the protonâneutron 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 â and the other one to an angle larger than 100 â 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 protonâproton case at very low relative energies. For the protonâneutron 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