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The vector analyzing power has been measured for the elastic scattering of neutron-rich He from polarized protons at 71 MeV/nucleon. Two approaches based on local one-body potentials were applied to investigate the spin-orbit interaction between a proton and a He nucleus. An optical model analysis revealed that the spin-orbit potential for He is characterized by a shallow and long-ranged shape compared with the global systematics of stable nuclei. A semi-microscopic analysis with a α + n + n cluster folding model suggests that the inclusion of realistic interaction between a proton and the α core is important in describing the p-He elastic scattering. [ABSTRACT FROM AUTHOR]

Recent results on the spin effects in deuteron inclusive breakup and deuteron-proton elastic scattering obtained at the Veksler and Baldin Laboratory of High Energies at JINR are reported. The experimental data have been obtained with the use of a high-energy polarized deuteron beam at the Synchrophasotron-Nuclotron Accelerator Complex. The covered energy range corresponds to the short internucleonic distances where the relativistic effects and non-nucleonic degrees of freedom can play a significant role. [ABSTRACT FROM AUTHOR]

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 E d lab = 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. [ABSTRACT FROM AUTHOR]

We have constructed a new type of spin polarized solid proton target which can be operated under a low magnetic field of 0.08T and a high temperature of 100K. We have measured for the first time the polarization asymmetry of an unstable beam of 6He at an energy of 71MeV/ u. Optical potential analyses have been carried out. [ABSTRACT FROM AUTHOR]

The 12C excitation energy spectra populated in both proton and α-particle inelastic scattering measurements are examined. The data indicate the existence of a 2+ state at Ex = 9.75(0.15) MeV with a width of 750(150) keV. It is believed that this state corresponds to the 2+ excitation of the 7.65 MeV, 0+, Hoyle state, which acts as the main path by which carbon is synthesized in stars. A simultaneous Ä-matrix analysis of the two sets of data indicates that the 2+ state possesses a very large α-reduced width, approaching the Wigner limit. This would indicate that the state is associated with a highly clustered structure. The potential geometric arrangements of the clusters is discussed. [ABSTRACT FROM AUTHOR]

Background: The 14O(α,p) 17F reaction plays an important role as the trigger reaction for the x-ray burst. Purpose: The direct measurement of 14O(α,p) 17F was made for studying the resonant states in 18Ne and determining the reaction rate of 14O(α,p) 17F at astrophysical temperatures. Methods: The differential cross section of the 14O(α,p) 17F reaction was measured using a 2.5-MeV/u 14O radioactive beam and the thick target method in inverse kinematics. Three sets of ΔE-E Si telescopes were installed and coincidence measurements were performed. We analyzed single-proton decay events using the time-of-flight (TOF) information of the recoiling protons. Results: The excitation function of 14O(α,p) 17F was acquired for excitation energies between 7.2 and 10.4 MeV in 18Ne by considering the two channels which decay to the ground state and first excited state of 17F. Several new, as well as previously known, states in 18Ne were observed and their resonance parameters were extracted from R-matrix analysis. The contributions of four resonances over the excitation energy range, 7 < Ex < 8.2 MeV, to the 14O(α,p) 17F reaction rate were calculated. Conclusions: We observed very strong single-proton decay events, but did not observe strong double-proton decay events as in a previous study by Fu et al. The reaction rates contributed by the 7.35-, 7.58-, and 7.72-MeV states were estimated to be dominant at temperatures T9 > 2. Among these three states, the 7.35-MeV state was found to enhance the reaction rate by a factor of 10 greater than the other two resonance states. [ABSTRACT FROM AUTHOR]

The reduced transition probability B(E2;0+gs → 2+1) for 28S was obtained experimentally using Coulomb excitation at 53 MeV/nucleon. The resultant B(E2) value 181(31) e2frn4 is smaller than the expectation based on empirical B(E2) systematics. The double ratio |Mn/Mp|/(N/Z) of the 0+gs → 2+1 transition in 28S was determined to be 1.9(2) by evaluating the Mn value from the known B(E2) value of the mirror nucleus 28Mg, showing the hindrance of proton collectivity relative to that of neutrons. These results indicate the emergence of the magic number Z = 16 in the |Tz| =2 nucleus 28S. [ABSTRACT FROM AUTHOR]

A benchmark experiment on 208Pb shows that polarized proton inelastic scattering at very forward angles including 00 is a powerful tool for high-resolution studies of electric dipole (El) and spin magnetic dipole (MI) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted El polarizability leads to a neutron skin thickness rSkin = 0. 156+0.025-0.021 fm in 208Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars. [ABSTRACT FROM AUTHOR]

Abstract: We describe the neutron polarimeter NPOL3 for the measurement of polarization transfer observables with a typical high resolution of 300keV at . The NPOL3 system consists of three planes of neutron detectors. The first two planes for neutron polarization analysis are made of 20 sets of one-dimensional position-sensitive plastic scintillation counters with a size of 100cm 10cm 5cm, and they cover the area of . The last plane for detecting doubly scattered neutrons or recoiled protons is made of the two-dimensional position-sensitive liquid scintillation counter with a size of . The effective analyzing powers and double scattering efficiencies were measured by using the three kinds of polarized neutrons from the , , and reactions at . The performance of NPOL3 defined as are similar to that of the Indiana Neutron POLarimeter by taking into account for the counter configuration difference between these two neutron polarimeters. [Copyright &y& Elsevier]

We have constructed and tested a novel plastic-scintillator-based solid-state active proton target for use in nuclear spectroscopic studies with nuclear reactions induced by an ion beam in inverse kinematics. The active target system, named Stack Structure Solid organic Scintillator Active Target (S 4 AT), consists of five layers of plastic scintillators, each with a 1-mm thickness. To determine the reaction point in the thickness direction, we exploit the difference in the energy losses due to the beam particle and the charged reaction product(s) in the scintillator material. S 4 AT offers the prospect of a relatively thick target while maintaining a good energy resolution. By considering the relative energy loss between different layers, the energy loss contributed by coincident unreacted beam particles can be eliminated. Such a procedure, made possible by the multi-layer structure, is essential to eliminate the contribution from coincident unreacted beam particles, thus enabling its operation at a moderate beam intensity of up to a few Mcps. We evaluated the performance of S 4 AT by measuring the elastic proton–proton scattering using a 70-MeV proton beam at Cyclotron and Radioisotope Center (CYRIC), Tohoku University. [ABSTRACT FROM AUTHOR]

The change in the configuration of valence protons between the initial and final states in the neutrinoless double-β decay of 130Te→130Xe and 136Xe→136Ba has been determined by measuring the cross sections of the (d,³He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-β decay in these systems. [ABSTRACT FROM AUTHOR]