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A new technique to measure (p,n) charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used to study the 56Ni(p,n) reaction at 110 MeV/u. Gamow-Teller transition strengths from 56Ni to 56Cu were obtained and compared with shell-model predictions in the pf-shell using the KB3G and GXPF1A interactions. The calculations with the GXPF1A interaction reproduce the experimental GT strength distribution much better than the calculations that employed the KB3G interaction, indicating deficiencies in the spin-orbit and proton-neutron residual potentials for the latter. The results are important for improving the description of electron-capture rates on nuclei in the iron region, which are important for modeling the late evolution of core-collapse and thermonuclear supernovae. [ABSTRACT FROM AUTHOR]

The isovector spin monopole resonances (IVSMR) of the β+ type were observed for the first time in the 208Pb and 90Zr(t,3He) reactions at 300 MeV/u. The experiment was performed at the RI Beam Factory (RIBF) at RIKEN by using the newly-constructed magnetic spectrometer SHARAQ. The double differential cross sections for the 208Pb and 90Zr(t,3He) reactions were obtained at the excitation energy of 0≤Ex≤70 MeV and the scattering angles of 0°≤θ≤3°. The monopole component was identified by making a difference between the zero-degree and backward-angle spectra. The signatures of the IVSMR are observed at an excitation energy of 12 MeV(20 MeV) in 208Pb(90Zr)(t,3He) reaction, which agrees fairly well with the theoretical predictions. [ABSTRACT FROM AUTHOR]

The high-resolution SHARAQ spectrometer and the dedicated high-resolution beam-line have been constructed at the RI beam factory and commissioned in 2009. Multi-wire drift chambers placed in the beam-line and cathode read-out drift chambers placed at the SHARAQ focal plane worked well for heavy ion beams with Z=1–7 at 200–300 MeV/nucleon. By introducing a dispersion matched operation of the beam-line, we have achieved a momentum resolution of δp/p = 1/8100 for a primary beam of 14N beam with a momentum spread of ±0.1%. Experiments by use of novel RI-beam induced charge exchange reactions are planned. [ABSTRACT FROM AUTHOR]

The high-resolution SHARAQ spectrometer and the dedicated high-resolution beamline have been constructed at RI beam factory and commissioned in 2009. Lateral and angular dispersion matching conditions were achieved simultaneously for a primay beam with a momentum spread of 0.1% and an emittance of 3π mm·mrad (σ). An overview of the spectrometer and the beam-line, preliminary results from the commissioning runs, and future experimental plan with the system are described. [ABSTRACT FROM AUTHOR]

The double differential cross sections for the 116Cd(p,n) and 116Sn(n,p) reactions at 300 MeV have been measured over a wide excitation-energy region including Gamow-Teller (GT) giant resonance (GTGR) for studying GT transition strengths in the intermediate nucleus of the 116Cd double-β decay, namely 116In. A large amount of the strengths in the β+ direction has been newly found in the energy region up to 30 MeV, which may imply that the GT strengths in the GTGR region contribute to the nuclear matrix element of the two-neutrino double-β decay. [ABSTRACT FROM AUTHOR]

Angular distributions of the double differential cross sections for the 48Ca(p,n) and the 48Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) transition strengths. In the (n, p) spectrum beyond 8 MeV excitation energy extra B(GT+) strengths which are not predicted by the shell model calculation. This extra B(GT+) strengths significantly contribute to the nuclear matrix element of the 2v2β-decay. [ABSTRACT FROM AUTHOR]

Recently it was found that the differential cross sections of elastic Nd scattering below 150 MeV can be well reproduced by incorporating a 3NF in Faddeev calculations based on modern nucleon-nucleon (NN) interactions. On the other hand, the differential cross sections for nd and pd at 250 MeV show large discrepancies between the data and the Faddeev calculations with a 3NF. This indicates the existence of the missing features of the three nucleon force in this energy region. For the next step in the 3NF study, we have measured the vector analyzing power Ay and the differential cross sections for the 2H(pvector ,pp)n breakup reaction at 250 MeV. The experiment was carried out by detecting two protons in the final state with using the double-armed spectrometer Grand Raiden (GR) and the Large Acceptance Spectrometer (LAS) at the Research Center for Nuclear Physics (RCNP). The data was compared with the results of Faddeev calculations with and without a 3NF. [ABSTRACT FROM AUTHOR]

Data for the deuteron analyzing powers in the dd→3Hen(3Hp) reactions obtained at 140–270 MeV are discussed. The observed negative sign of the tensor analyzing powers Ayy, Axx and Axz at small angles clearly demonstrate the sensitivity to the ratio of the D and S state components of the 3He wave function. The behavior of the tensor analyzing powers at backward angles is sensitive to the short-range spin structure of the deuteron. However, the one-nucleon exchange calculations using standard 3He and deuteron wave functions fail to reproduce the strong variation of the tensor analyzing powers as a function of angle in the cms. Sensitivity to relativistic effects is also discussed. [ABSTRACT FROM AUTHOR]

CANDLES is the project to search for double beta decay of 48Ca by using CaF2 crystals. Double beta decay of 48Ca has the highest Q value among all nuclei whose double beta decay is energetically allowed. This feature makes the study almost background free and becomes important once the study is limited by the backgrounds. We studied double beta decays of 48Ca by using ELEGANTS VI detector system which features CaF2(Eu) crystals. We gave the best limit on the lifetime of neutrino-less double beta decay of 48Ca although further development is vital to reach the neutrino mass of current interest for which CANDLES is designed. In this article we present how CANDLES can achieve low radioactivity, which is the key for the future double beta decay experiment. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We have measured the neutron-deuteron (nd) elastic-scattering differential cross section at 95 MeV incident neutron energy, using both the Medley and the SCANDAL setups at TSL in Uppsala. The full angular distribution was covered by detecting recoil deuterons from thin CD2 targets, and the result was normalized to the neutron-proton (np) cross section. Recent theories predict that three-nucleon (3N) force effects, if present, would affect the cross section in the minimum region by about 30%. The results are compared with theoretical calculations and are well described if 3N forces are included. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A new type of the spin polarized solid proton target has been constructed which can be operated under a low magnetic field of 0.08 T and a high temperature of 100 K. First polarization asymmetry measurement with an unstable beam of 6He with an energy of 71 MeV/u has been successfully carried out. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The University of Tokyo has been promoting a future project to construct a third-generation VUV and Soft X-ray light source (Super SOR). The Super SOR ring has energy of 1.8 GeV (max. 20 GeV), an emittance of about 8 nm•rad, a circumference of about 280 m. It consists of fourteen Chasman-Green type cells and has two 17 m long straight sections and twelve 6 m long ones. It can provide the VUV and Soft X-ray light with maximum brilliance above 1019 [photons/sec/mm2/mrad2/0.1% b.w.]. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

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. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

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. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

A complete set of polarization transfer coefficients has been measured for the quasi-elastic 12C(pvector ,nvector ) 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. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

A method of model-independent spin-parity determination is proposed for the (d, 2He) reaction by using the tensor analyzing power Azz at θ = 0°, which shows extreme values for 0- and natural-parity states solely by parity-conservation. It is applied to the 12C(d, 2He)12B reaction at Ed = 270 MeV and a possible indication of 0- state is found at Ex = 9.3 MeV in 12B. The bump at Ex = 7.5 MeV appears to have more 2- strength than 1- strength, consistent with our earlier work. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

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. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

The results of experimental studies of three-nucleon systems will be presented, i.e. the pvector d elastic scattering at Ep = 250 MeV and the dvector p → 3He+γ capture reaction at Ed = 200 MeV. The angular distributions of the cross section and all the proton spin observables were measured for elastic scattering, and the cross section and analyzing powers, Ay, Axx and Ayy for the capture reaction. The results are compared with theoretical predictions based on exact solutions of the three-nucleon Faddeev equations and modern realistic nucleon-nucleon potentials combined with three-nucleon forces. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Measurements of the tensor and vector analyzing powers Ayy, Axx, Axz, and Ay for the dvector d → 3Hen and dvector d → 3Hp reactions were performed at Ed = 270 and 200 MeV over wide angular range. T20 at θcm = 0° and 180° were also measured at Ed = 270, 200, and 140 MeV. Obtained data were compared with predictions based on one nucleon exchange approximation. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

A polarized solid proton target system that can be used for radioisotope beam experiments has being developed. A high-power Ar-ion laser has been installed to improve proton polarization. With the laser, proton polarization of 36.8±4.2% has been achieved in 0.3 T at 77 K. The new target system has been constructed toward the first nuclear physics experiment scheduled in 2003. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Precise data on cross sections, analyzing powers and polarization transfer coefficients are measured for the dp elastic scattering at 270 MeV (135 MeV/nucleon) and compared to Faddeev calculations assuming the nd scattering with modern nucleon-nucleon (NN) forces including the 2π exchange Tucson-Melbourne (TM) three-nucleon (3N) force. Excellent fits are obtained for the cross sections and vector analyzing powers when the 3N force is included, while the fits are deteriorated for the tensor analyzing powers if the 3N force is included. A moderate fit is obtained for the polarization transfer coefficients. Based on theses results, one can conclude that the size of amplitudes of the TM-3N force may be adequate but the spin dependent part may be deficient. The cross sections and the vector analyzing powers for the nd elastic scattering at 250 MeV are measured for the first time. Backward cross sections are underestimated by the NN+3N force Faddeev calculations. This difference might be attributed to relativistic effects. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A complete set of polarization transfer coefficients has been measured for quasielastic (&prarr;, ↛) reactions on ²H and [sup 12]C at a bombarding energy of 346 MeV and laboratory scattering angles of 16°, 22°, and 27°. The spin-longitudinal ID[sub q] and spin-transverse ID[sub p] polarized cross sections are deduced. The theoretically expected enhancement in the spin-longitudinal mode is observed. The observed ID[sub q] is consistent with the pionic enhanced ID[sub q] 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 ID[sub p] is not quenched, but rather enhanced in comparison with the DWIA+RPA calculation. [ABSTRACT FROM AUTHOR]

Spin-flip probabilities and the differential cross sections for the [sup 26]Mg(³He,t)[sup 26]Al[sup *](l[sup +];1.058 MeV) reaction have been measured at E[sub 3[sub He]]=177 MeV. This is the first spin-flip probability data for the (³He,t) reaction in the energy region above 20 MeV/A. The data are compared with distorted wave Born approximation calculations by using the ³He-n effective interaction extracted from the differential cross sections. [ABSTRACT FROM AUTHOR]

Polarization observables for the ³He(↘, p)[sup 4]He reaction have been measured at E[sub 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. Data are compared with impulse approximation calculation based on the three-nucleon scattering amplitudes. [ABSTRACT FROM AUTHOR]

The differential cross sections and vector analyzing powers for the ↛d elastic scattering at E[sub n] = 250 MeV have been measured at θ[sub cm] = 85° - 180°. Our aims are to study the three-nucleon force (3NF) without ambiguities from the Coulomb effect. The data are compared to the results of Faddeev calculations using modern nucleonnucleon (NN) forces with and without 3NF. It is found that the calculations better reproduce the cross sections by including the 3NF but still underestimate the data. [ABSTRACT FROM AUTHOR]

Precise measurements of the cross sections and deuteron analyzing powers (A[sub y], A[sub yy], A[sub xx] and A[sub xz]) for the d-p elastic scattering has been made at E[sub d] = 140, 200 and 270 MeV at RIKEN Accelerator Research Facility. The obtained results are compared with the Faddeev calculations based on modern nucleon-nucleon forces together with Tucson-Melbourne type and Urbana-Argonne type of three nucleon forces. [ABSTRACT FROM AUTHOR]

We report measurements of the deuteron single and double spin-flip probabilities (SFPs), S[sub 1] and S[sub 2], for the (↘, ↘') reaction on [sup 12]C and [sup 28]Si at 270 MeV over an excitation energy range of 4-24 MeV and a scattering angular range of 2.5-7.5°. The SFP S[sub 1] exhibits large positive values for known spin-flip states, while it has values close to zero for non-spin-flip states. The SFP S[sub 2] is close to zero for all the measured excitation energy region. The results for the 1[sup +] (12.71 MeV) and 2[sup +] (4.44 MeV) states in [sup 12]C are well described by the microscopic DWIA calculations. The deuteron SFPs provide signatures of isoscalar single and double spin-flip nuclear excitations. [ABSTRACT FROM AUTHOR]

Theoretical investigations and measurements have been performed to reproduce the experimental data for the [sup 12,13]C(p, π[sup -]) reactions near threshold energies and to investigate the role of the delta resonance in the (p, π[sup -]) reactions to ground states. In order to clarify the reaction mechanism, it is inevitable to study the energy dependence of the cross section and the asymmetry. In the present paper, angular distributions of cross sections and analyzing powers were measured for [sup 12,13]C(p, π[sub ±]) reactions leading to ground states of the residual nuclei at incident energies of 250, 300 and 350 MeV. Experimental results are compared with the full-range DWBA calculations. [ABSTRACT FROM AUTHOR]

We have calibrated the effective analyzing powers of the deuteron polarimeter, DPOL, in the deuteron energy region of 210 < E[sub d] < 270 MeV. The calibration was needed to analyze the polarization transfer measurement for the [sup 12]C(↘, ↘') reaction at 270 McV whose aim is to search for Double Gamow-Teller resonances in [sup 12]C in an excitation energy region of E[sub x] < 60 MeV. [ABSTRACT FROM AUTHOR]

The [sup 12]C(↘, α)[sup 10]B*(2[sup +]) reaction at 0° is proposed as a new standard for the deuteron beam polarization at an intermediate energy region. The absolute value of the polarization is measured using this reaction at 270 and 140 MeV deuteron energies for the first time. The obtained beam polarization is used for the calibration of the analyzing powers for the ↘-p elastic scattering which we use as a polarimetry. The result is almost consistent with the data of the previous calibrations. [ABSTRACT FROM AUTHOR]