T. Uesaka

Cluster states in 13C

Cross sections for 13C(α,α′) reactions at Eα = 400 MeV have been measured to obtain the monopole and quadrupole transition strengths. The excitation strengths are compared with the shell-model predictions. It is suggested that the large monopole strengths observed for the

Spin-flip strength in the continuum and effective tensor interactions via polarization transfer {ital D}{sub {ital NN}}(0{degree}) for ({ital {rvec p}},{ital {rvec n}}) reactions at 295 MeV

1/2^-_2

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

and

ANALYZING POWERS MEASUREMENT FOR d - p ELASTIC SCATTERING AT THE INTERNAL TARGET STATION OF NUCLOTRON

1/2^-_3

Gamow–Teller strength in the continuum and quenching problem

states in 13C are attributed to the cluster structure of those states.

Observation of the Isovector Giant Monopole Resonance via the Si 28 (Be 10, B∗ 10 [1.74 MeV]) Reaction at 100 AMeV

The first measurements of {ital D}{sub {ital NN}}(0{degree}) for ({ital {rvec p}},{ital {rvec n}}) reactions at 295 MeV yield large negative values up to 50 MeV excitation for the {sup 6}Li,{sup 11}B,{sup 12}C, {sup 13}C({ital {rvec p}},{ital {rvec n}}) reactions, suggesting much stronger spin-flip strength than observed at lower bombarding energies. DWIA calculations using the Franey and Love (FL) 270 MeV interaction reproduce differential cross sections and {ital D}{sub {ital NN}}(0{degree}) values, while the FL 325 MeV interaction yield {ital D}{sub {ital NN}}(0{degree}) values less negative than the experimental values, suggesting that its exchange tensor part is too strong at large momentum transfer ({ital Q}{congruent}3.4 fm{sup {minus}1}).

The Spin Studies in Few-Body Systems at Nuclotron

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.

THE ANGULAR DISTRIBUTIONS OF THE VECTOR Ay AND TENSOR Ayy, Axx, Axz ANALYZING POWERS IN THE dd → 3Hp AND dd → 3Hen REACTIONS AT Ed = 200 AND 270 MeV

Analyzing powers measurement Ay, Ayy and Axx for the d - p elastic scattering were performed at the Internal Target Station of Nuclotron at JINR at Ed = 880 and 2000 MeV. These data are necessary to obtain the information on the 3NF structure and the relativistic effects. They are also important for development of the efficient deuteron beam polarimetry at high energies. The results of the analyzing powers at Ed = 880 MeV covered the angular range from 60 to 140° in the c.m.s. are compared with several theoretical calculations. The preliminary data on the analyzing powers measurement Ay, Ayy at Ed = 2000 MeV are discussed.

A Model for the Reaction at Intermediate Energies

Abstract Differential cross sections at θlab = 0.0°–12.3° and a complete set of polarization transfer observables at θlab = 0.0° are measured for the 90Zr(p, n) reaction at Tp = 295 MeV. A multipole decomposition (MD) technique is applied to the cross sections to extract partial cross sections σL with L=0, 1, 2, and 3 contributions. A significant amount of σL=0 is found in the highly excited continuum region. After subtracting the estimated iso-vector spin-monopole strength from σL=0, the Gamow-Teller (GT) strength B(GT) is deduced to be Sβ− = Σ B(GT) = 28 ± 1.6 ± 5.4. The total spin transfer Σ(0°) which is independent of the nuclear reaction mechanisms such as the effective nucleon-nucleon interaction or distortions is derived from the complete set of polarization transfer observables. It is close to unity up to 50 MeV excitation indicating the strong spin-flip character of the continuum. By using the relation between the polarization transfer observables the fractions of natural-parity and unnatural-parity transitions are also obtained and the dominance of unnatural-parity transitions in the continuum is found. These results are consistent with those derived from the MD analysis. The Sβ− − Sβ+ value is 27.1 and this is 90% of Ikedas sum rule value of 3(N - Z)=30. Consequently it is concluded that the quenching of the GT strength is small and the quenching mechanism due to the ΔN− admixture seems to play a minor role.

Geochemical Determination of the Solar pp-Neutrino Flux with LOREX: A Progress Report

The (^{10}Be,^{10}B^{*}[1.74  MeV]) charge-exchange reaction at 100  AMeV is presented as a new probe for isolating the isovector (ΔT=1) nonspin-transfer (ΔS=0) response of nuclei, with ^{28}Si being the first nucleus studied. By using a secondary ^{10}Be beam produced by fast fragmentation of ^{18}O nuclei at the NSCL Coupled Cyclotron Facility, applying the dispersion-matching technique with the S800 magnetic spectrometer to determine the excitation energy in ^{28}Al, and performing high-resolution γ-ray tracking with the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) to identify the 1022-keV γ ray associated with the decay from the 1.74-MeV T=1 isobaric analog state in ^{10}B, a ΔS=0 excitation-energy spectrum in ^{28}Al was extracted. Monopole and dipole contributions were determined through a multipole-decomposition analysis, and the isovector giant dipole resonance and isovector giant monopole resonance (IVGMR) were identified. The results show that this probe is a powerful tool for studying the elusive IVGMR, which is of interest for performing stringent tests of modern density functional theories at high excitation energies and for constraining the bulk properties of nuclei and nuclear matter. The extracted distributions were compared with theoretical calculations based on the normal-modes formalism and the proton-neutron relativistic time-blocking approximation. Calculated cross sections based on these strengths underestimate the data by about a factor of 2, which likely indicates deficiencies in the reaction calculations based on the distorted wave Born approximation.