Hideyuki Sakai

The Landau-Migdal parameters, g′NN and g′NΔ

The Landau-Migdal parameters for nucleon-nucleon (g_NN) and nucleon-Delta (g_NDelta) couplings are estimated from recent experimental data on the giant Gamow-Teller state of 90Nb. The observed quenching of the GT strength by 10% provides 0.16<g_NDelta<0.23 for g_DeltaDelta <1.0, while the excitation energy g_NNsim 0.59. The critical density of pion condensations is much lower than those previously discussed with the universality ansatz.

Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering

Abstract.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. Angular distributions in the range of 70°-120° in the center-of mass frame for incident-deuteron energies Edlab = 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring the ^12C (d, α)^10B(2+) reaction at 0°. 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.

Spin-isospin selectivity in three-nucleon forces

Abstract Precision data are presented for the break-up reaction, H 2 ( p → , p p ) n , within the framework of nuclear-force studies. The experiment was carried out at KVI using a polarized-proton beam of 190 MeV impinging on a liquid-deuterium target and by exploiting the detector, BINA. Some of the vector-analyzing powers are presented and compared with state-of-the-art Faddeev calculations including three-nucleon forces effect. Significant discrepancies between the data and theoretical predictions were observed for kinematical configurations which correspond to the H 2 ( p → , He 2 ) n channel. These results are compared to the H 2 ( p → , d ) p reaction to test the isospin sensitivity of the present three-nucleon force models. The current modeling of two and three-nucleon forces is not sufficient to describe consistently polarization data for both isospin states.

Pulse shape simulation and analysis of segmented Ge detectors for position extraction

A simulation method, which can predict the relation between the pulse shapes and the interaction points of incident /spl gamma/-rays, has been established for the entire effective volume of a segmented Ge detector with planar geometry, and the pulse shapes shows good agreement with the experimental observation. We are using pulse shape analysis to gain position information with a granularity finer than the segment size, and we will discuss the expected position resolution based on the simulation results.

(3He,t) Charge-Exchange Reactions at E(3He) = 450 MeV, θ = 0°

Spin-isospin excitations in nuclei have been studied by means of the (3He,t) reactions at 450 MeV on the targets sBe, natC, *%ii, 58Ni, 62Ni, seZr, l18Sn, **OSn, 124Sn, and 154Sm. The new spectrometer “Grand Raiden” was employed for the (3He,t) study for the first time. Observed (3He,t) spectra at 0’ show remarkable similarity with those from the (p,n) results at intermediate energies, suggesting a simple direct reaction mechanism for the (3He,t) reaction at 450 MeV. The GamowTeller (GT) resonances and the spin-flip AL=1 resonances are excited very strongly. A fine structure of the GT resonances in medium-heavy nuclei is observed with an energy resolution of 210 keV. It is demonstrated that the (3He,t) reaction at 450 MeV is a powerful tool to study the spin-isospin excitations in nuclei.

Measurements of NE-213 response functions to neutrons of energies up to several tens of MeV

Abstract Measurements of neutron response functions of a 3 in. × 3 in. NE-213 scintillator were made for neutron energies from 10 MeV to 73 MeV using neutrons from a quasi-monoenergetic neutron source of p- 7 Li and a white source from thick Be and Cu targets. Neutrons sampled into small energy bins by TOF signals were utilized in the response measurements. Response functions calculated by the Monte Carlo method were compared with the measured data, thus clearing problems in the calculation model. Based on the measured and calculated data, a new response matrix which covered from 0 to 76 MeV was constructed. The matrix was successfully applied to unfold a pulse-height spectrum of up to several tens of MeV neutrons that were transmitted through a 50 cm concrete shield.

Unified analysis of spin isospin responses of nuclei

We investigate the Gamow-Teller (GT) response functions at a momentum transfer of

New Experimental Studies of Nuclear Spin-Isospin Responses

q=0phantom{rule{0.3em}{0ex}}{mathrm{fm}}^{ensuremath{-}1}

Transmission of Intermediate-Energy Neutrons and Associated Gamma Rays Through Iron, Lead, Graphite, and Concrete Shields

and the pionic response functions for quasielastic scattering (QES) at

Total Spin Transfer in Continuum for 90Zr(p,n) Reaction at 295 MeV

qensuremath{approx}1.7phantom{rule{0.3em}{0ex}}{mathrm{fm}}^{ensuremath{-}1}