Publications (19)34.91 Total impact
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ABSTRACT: Differential cross sections and complete sets of polarization observables are presented for the GamowTeller 12C(p⃗,n⃗)12N(g.s.,1+) reaction at a bombarding energy of 296 MeV with momentum transfers q of 0.1 to 2.2 fm1. The polarization transfer observables are used to deduce the spinlongitudinal cross section, IDq, and spintransverse cross sections, IDp and IDn. The data are compared with calculations based on the distortedwave impulse approximation (DWIA) using shellmodel wave functions. Significant differences between the experimental and theoretical results are observed for all three spindependent IDi at momentum transfers of q≳0.5 fm1, suggesting the existence of nuclear correlations beyond the shell model. We also performed DWIA calculations employing randomphase approximation (RPA) response functions and found that the observed discrepancy is partly resolved by the pionic and ρmesonic correlation effects. 
Article: Study of ¹²C(pvector,nvector)¹²N(g.s.;1{sup +}) at 296 MeV and Nuclear Correlation Effects
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ABSTRACT: We present measurements of the cross section and a complete set of polarization observables for the GamowTeller ¹²C(pvector,nvector)¹²N(g.s.;1{sup +}) reaction at an incident proton energy of 296 MeV. The complete set of polarization observables is used to separate the cross section into spinlongitudinal and spintransverse components. From the comparison with the distorted wave impulse approximation calculations employing random phase approximation response functions, we found that our data showed the existence of the pionic and rhomesonic correlations in nuclei.  [Show abstract] [Hide abstract]
ABSTRACT: The doubledifferential cross sections for the 48Ca(p,n) and 48Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the GamowTeller (GT) components. The integrated GT strengths up to an excitation energy of 30 MeV in 48Sc are 15.3+/2.2 and 2.8+/0.3 in the (p,n) and (n,p) spectra, respectively. In the (n,p) spectra additional GT strengths were found above 8 MeV where shell models within the fp shellmodel space predict almost no GT strengths, suggesting that the present shellmodel description of the nuclear matrix element of the twoneutrino doublebeta decay is incomplete. 
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ABSTRACT: In our previous measurement of pd radiative capture at E d = 137 and 196 MeV, we found an interesting fact that the measured tensor analyzing powers show the relation A xx ≈ A yy , although calculated A xx and A yy are apparently different, A xx != A yy . The measured A yy agrees fairly well with the 3 N calculations, and the measured A xx largely disagrees with calculated A xx . Similar experiments on pd capture have been made at KVI at nearly the same energies of 130180 MeV. The KVI data also support A xx ≈ A yy relation, but absolute values of A xx and A yy at KVI are about half of RCNP data. Therefore, we made a new experiment of pd capture at E d = 196 MeV. A zz was measured in three different ways, and data analysis is in progress. Preliminary data seem to support our previous data.  [Show abstract] [Hide abstract]
ABSTRACT: The cross sections and analyzing powers for (p,n) reactions on 3He and 4He have been measured at a bombarding energy of Tp=346 MeV and reaction angles of θlab=9.4°27°. The energy transfer spectra for 3He(p,n) at large θlab (⩾16°) are dominated by quasielastic contributions and can be reasonably reproduced by planewave impulse approximation (PWIA) calculations for quasielastic scattering. By contrast, the known L=1 resonances in 4Li are clearly observed near the threshold in the 4He(p,n) spectra. Because these contributions are remarkable at small angles, the energy spectra are significantly different from those expected for quasielastic scattering. The data are compared with the PWIA calculations, and it is found that the quasielastic contributions are dominant at large θlab (⩾22°). The nuclear correlation effects on the quasielastic peak for 4He(p,n) are also discussed. 
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ABSTRACT: We report measurements of the crosssection and a complete set of polarization transfer coefficients for the 3He(p,n) reaction at a bombarding energy Tp=346 MeV and a reaction angle θlab=0°. The data are compared with the corresponding free nucleonnucleon values on the basis of the predominance of quasielastic scattering processes. Significant discrepancies have been observed in the polarization transfer DLL(0°), which are presumably the result of the threeproton T=3/2 resonance. The spinparity of the resonance is estimated to be 1/2, and the distribution is consistent with previous results obtained for the same reaction at Tp=48.8 MeV.  [Show abstract] [Hide abstract]
ABSTRACT: 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 nucleonnucleon (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(pvec ,pp)n breakup reaction at 250 MeV. The experiment was carried out by detecting two protons in the final state with using the doublearmed 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.  [Show abstract] [Hide abstract]
ABSTRACT: Keywords: polarized 3He, metastability exchange, infrared laser 
Article: Complete Set of Polarization Transfer Observables for the 12C( p,n) Reaction at 296 MeV and 0\circ
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ABSTRACT: A complete set of polarization transfer observables has been measured for the 12C( p,n) reaction at Tp=296 MeV and θlab=0\circ. The measured polarization transfer observables indicate that the spindipole resonance at Ex ≃ 7 MeV has greater 2 strength than 1 strength, which is consistent with recent experimental and theoretical studies. The total spin transfer Σ(0\circ) deduced from the polarization transfer observables indicates a predominance of the spinflip strength in the continuum. The exchange tensor interaction at a large momentum transfer of Q ≃ 3.6 fm1 is discussed.  [Show abstract] [Hide abstract]
ABSTRACT: We report measurements of the cross section and a complete set of polarization observables for the Gamow–Teller C12(p→,n→)N12(g.s.,1+) reaction at a bombarding energy of 296 MeV. The data are compared with distorted wave impulse approximation calculations employing transition form factors normalized to reproduce the observed betadecay ft value. The cross section is significantly underpredicted by the calculations at momentum transfers q≳0.5 fm−1q≳0.5 fm−1. The discrepancy is partly resolved by considering the nonlocality of the nuclear mean field. However, the calculations still underpredict the cross section at large momentum transfers of q≃1.6 fm−1q≃1.6 fm−1. We also performed calculations employing random phase approximation response functions and found that the observed enhancement can be attributed in part to pionic correlations in nuclei.  [Show abstract] [Hide abstract]
ABSTRACT: We report measurements of the cross section and a complete set of polarization observables for the GamowTeller ${}^{12}{\rm C}(\vec{p},\vec{n}){}^{12}{\rm N}({\rm g.s.},1^+)$ reaction at a bombarding energy of 296 MeV. The data are compared with distorted wave impulse approximation calculations employing transition form factors normalized to reproduce the observed betadecay $ft$ value. The cross section is significantly underpredicted by the calculations at momentum transfers $q \gtrsim $ 0.5 ${\rm fm^{1}}$. The discrepancy is partly resolved by considering the nonlocality of the nuclear mean field. However, the calculations still underpredict the cross section at large momentum transfers of $q$ $\simeq$ 1.6 ${\rm fm^{1}}$. We also performed calculations employing random phase approximation response functions and found that the observed enhancement can be attributed in part to pionic correlations in nuclei.  [Show abstract] [Hide abstract]
ABSTRACT: Inelastic α scattering on 16O is studied at 400 MeV using an ice target. Near the 4α breakup threshold of 14.4 MeV, a broad peak is observed at an excitation energy of 13.6±0.1 MeV with a width of 0.6±0.2 MeV. The spinparity is estimated to be 0+ from the momentumtransfer dependence. The observed width is significantly larger than that of the 0+ state at 12.0 MeV with the structure, indicating a welldeveloped α cluster structure. The magnitude of the cross section is sensitive to the density distribution of the constituent α clusters. The observed cross section is consistent with the theoretical prediction for the α cluster condensed state, characterized by its dilute density distribution with a large rootmeansquare radius.  [Show abstract] [Hide abstract]
ABSTRACT: The short range component of the nucleonnucleus interaction is phenomenologically described by effective interaction including the socalled LandauMigdal parameters g', among which only g{sub {delta}}{sub {delta}}{sup '} has been left unfixed because of the scarcity of experimental information. We propose Coherent Pion Production (CPP) measurement 12C(p, n{pi}+)12C(g.s.) to get quantitative information on g{sub {delta}}{sub {delta}}{sup '}. A preliminary CPP experiment was performed at the RCNP neutron time of flight facility by involving exclusive measurement of pions and neutrons. We have specially developed for this purpose a new pion counter and embedded it in the beam swinger magnet of the neutron time of flight facility. We describe the experiment and preliminary result from the pionneutron coincidences. 
Article: Measurement of cross section and various spin observables in the pd elastic scattering at 392 MeV
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ABSTRACT: The cross sections and spin observables of the pd elastic scattering have been measured at 392 MeV. The results are compared with the prediction of Faddeev calculations with and without including a three nucleon force.  [Show abstract] [Hide abstract]
ABSTRACT: 12 pages, 5 fugures, submitted to Phys. Lett. B  PTH  [Show abstract] [Hide abstract]
ABSTRACT: Differential cross sections and complete sets of polarization observables are presented for the GamowTeller 12C(~ p, ~ n )12N(g.s.,1+) reaction at a bombarding energy of 296 MeV with momentum transfers q of 0.1 to 2.2 fm−1. The polarization transfer observables are used to deduce the spin longitudinal cross section, IDq, and spintransverse cross sections, IDp and IDn. The data are compared with calculations based on the distorted wave impulse approximation (DWIA) using shellmodel wave functions. Significant differences between the experimental and theoretical results are observed for all three spindependent IDi at momentum transfers of q & 0.5 fm−1, suggesting the existence of nuclear correlations beyond the shell model. We also performed DWIA calculations employing random phase approximation (RPA) response functions and found that the observed discrepancy is partly resolved by the pionic and rhomesonic correlation effects. 
Article: reaction at 346 MeV and 0 degrees
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ABSTRACT: We report measurements of the crosssection and a complete set of polarization transfer coeffi cients for the 3He(p,n) reaction at a bombarding energy Tp = 346 MeV and a reaction anglelab = 0◦. The data are compared with the corresponding free nucleonnucleon values on the basis of the predominance of quasielastic scattering processes. Significant discrepancies have been observed in the polarization transfer DLL(0◦), which are presumably the result of the threeproton T = 3/2 resonance. The spinparity of the resonance is estimated to be 1/2−, and the distribution is consistent with previous results obtained for the same reaction at Tp = 48.8 MeV.
Publication Stats
110  Citations  
34.91  Total Impact Points  
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Institutions

20072009

Kyushu University
 Department of Physics
Hukuoka, Fukuoka, Japan
