K. Suda

Three-body dN interaction in the analysis of the 12C(d→,d′) reaction at 270 MeV

Abstract We have measured the cross sections and analyzing powers A y and A yy for the elastic and inelastic scattering of deuterons from the 0 + (g.s.), 2 + (4.44xa0MeV), 3 − (9.64xa0MeV), 1 + (12.71xa0MeV), and 2 − (18.3xa0MeV) states in 12 C at an incident energy of 270xa0MeV. The data are compared with microscopic distorted-wave impulse approximation calculations where the projectile-nucleon effective interaction is taken from the three-nucleon t -matrix given by rigorous Faddeev calculations presently available at intermediate energies. The agreement between theory and data compares well with that for the ( p , p ′) reactions at comparable incident energies/nucleon.

\({}^3\overrightarrow {{\rm{He}}} {\rm{ (}}\vec d,p{)^4}{\rm{He}}\) Reaction at Intermediate Energies

We have measured the cross sections and the polarization observables for the 3He(d,p)4He reaction at E d =140, 200, and 270 MeV. This work aims to investigate the high momentum component of deuteron D-state wave function and the mechanism for the one-nucleon transfer reaction at intermediate energies. The measurement was carried out by using the spectrograph SMART at RIKEN Accelerator Research Facility. A cryogenic 3He gas target with a density of 6.6×1020 cm−3 was bombarded by a polarized deuteron beam. The data are compared with the calculation based on the one-nucleon exchange approximation.

Reaction mechanism and characteristics ofT20ind+3Hebackward elastic scattering at intermediate energies

For backward elastic scattering of deuterons by ^3He, cross sections sigma and tensor analyzing power T_{20} are measured at E_d=140-270 MeV. The data are analyzed by the PWIA and by the general formula which includes virtual excitations of other channels, with the assumption of the proton transfer from ^3He to the deuteron. Using ^3He wave functions calculated by the Faddeev equation, the PWIA describes global features of the experimental data, while the virtual excitation effects are important for quantitative fits to the T_{20} data. Theoretical predictions on T_{20}, K_y^y (polarization transfer coefficient) and C_{yy} (spin correlation coefficient) are provided up to GeV energies.

Determination of the Gamow‐Teller Quenching Factor via the90Zr(n, p) Reaction at 293 MeV

The double differential cross sections at 0°–12° were measured for the 90Zr(n,p) reaction at 293 MeV in a wide excitation energy region of 0–70 MeV. The experiment was performed by using the (n,p) facility at the Research Center for Nuclear Physics. The multipole decomposition (MD) technique was applied to the measured cross sections to extract the GT component in the continuum. After subtracting the contribution of the isovector spin‐monopole excitation we obtained the GT strength of Sβ+ = 3.0 ± 0.3 ± 0.8 ± 0.5 up to 31.4 MeV excitation. The quenching factor Q was deduced by using the present result and the Sβ− value obtained from the MD analysis of the 90Zr(p,n) spectra. The result is Q = 0.83 ± 0.06 in regards to Ikeda’s sum rule value of 3(N − Z) = 30.

A Model for the Reaction at Intermediate Energies

Polarization correlation coefficients have been measured atRIKEN for the vec 3He(vec d,p)4He reaction at intermediate energies. We propose a model for the (vec d, p) reaction mechanism using the pd elastic scattering amplitude which is rigorously determined by a Faddeev calculation and using modern NN forces. Our theoretical predictions for deuteron polarization observables A_y, A_{yy}, A_{xx} and A_{xz} at E_d=140, 200 and 270 MeV agree qualitatively in shape with the experimental data for the reaction 3He(vec d,p)4He.

Momentum transfer dependence of spin isospin modes in quasielastic (p⃗,n⃗) reactions

A complete set of polarization transfer coefficients has been measured for quasielastic (p,n) reactions on 2H and 12C at a bombarding energy of 346 MeV and laboratory scattering angles of 16°, 22°, and 27°. The spin-longitudinal IDq and spin-transverse IDp polarized cross sections are deduced. The theoretically expected enhancement in the spin-longitudinal mode is observed. The observed IDq is consistent with the pionic enhanced IDq evaluated in a distorted wave impulse approximation (DWIA) calculation employing a random phase approximation (RPA) response function. On the contrary, the theoretically predicted quenching in the spin-transverse mode is not observed. The observed IDp is not quenched, but rather enhanced in comparison with the DWIA+RPA calculation.

Precise Measurement of dp Scattering at 270 MeV

Precise data were obtained for the cross sections as well as the vector and tensor analyzing powers for the deuteron-proton elastic scattering at 270 MeV covering the scattering angles θ cm = 10° – 180°. In addition, the tensor-to-vector polarization transfer coefficients K xx y′ – K yy y′ have been measured for the first time at θ cm = 120°, 130° and 150°. These results have been compared to the Faddeev calculations with and without the three nucleon force.

Isoscalar Spin Response in the Continuum Studied via the 12C(d⃗,d⃗′) Reaction at 270 MeV

Single and double spin‐flip probabilities in inelastic deuteron scattering on 12C have been measured at 270 MeV up to 50 MeV in excitation energy using a focal plane deuteron polarimeter capable of measuring both vector and tensor components of the deuteron polarization. The obtained S1 values are enhanced relative to the Fermi gas model prediction in highly excited continuum region. The S2 values are close to zero over the measured excitation energy range.

Polarization Transfer Measurement for d‐p Elastic Scattering ‐ a Probe for Three Nucleon Force Properties ‐

Precise measurements of the deuteron to proton polarization transfer coefficients for the d‐p elastic scattering has been made at 135 MeV/u at RIKEN Accelerator Research Facility. The obtained results are compared with the Faddeev calculations based on modern nucleon‐nucleon forces together with Tucson‐Melbourne, Tucson‐Melbourne′ and Urbana‐Argonne type of three nucleon forces.

Momentum Transfer Dependence of Spin Isospin Modes in the Quasielastic Region

A complete set of polarization transfer coefficients has been measured for the quasi‐elastic 12C(p,n) reaction at a bombarding energy of 345 MeV and laboratory scattering angles of 16°, 22°, and 27°. The spin‐longitudinal IDq and spin‐transverse IDp polarized cross sections are deduced. The theoretically expected enhancement in the spin‐longitudinal mode is observed. The observed IDq is consistent with the pionic enhanced IDq evaluated in a distorted wave impulse approximation (DWIA) calculation employing a random phase approximation (RPA) response function. On the contrary, the theoretically predicted quenching in the spin‐transverse mode is not observed. The observed IDp is not quenched, but rather enhanced in comparison with the DWIA+RPA calculation. Two‐step contributions are responsible in part for the enhancement of ID p.