Publications (15)8.34 Total impact
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ABSTRACT: Space Star (SS) anomaly in nd breakup cross section was first reported in 1989 at E n = 13 MeV (Strate et al. in Nucl Phys A 501:51, 1989), but its origin has not been found yet. In order to obtain suggestions for its origin, we made systematic measurements of pd breakup cross section around SS. In SS configuration, three outgoing nucleons form an equilateral triangle and the triangle is perpendicular to the beam axis. Necessity of the equilateral and perpendicular conditions of SS anomaly was investigated by systematic experiments. Also energy dependence of SS anomaly is being studied at energies from E p = 7.5 to 13 MeV.  [Show abstract] [Hide abstract]
ABSTRACT: We report measurements of cross sections and analyzing powers for reaction angles of θlab = 0.0°10.0° and complete sets of polarization transfer observables and induced polarizations at θlab = 0.0°7.0° for the 208Pb(pvec ,nvec ) reaction at a bombarding energy of Tp = 296 MeV. A multipole decomposition technique was applied to the data to extract the spindipole (SD) components from the continuum. The polarization observables were also used, for the first time, to separate the SD components into different spinparity transfer (ΔJπ = 0, 1, and 2) contributions. The SD strength distributions were clearly dependent on ΔJπ, which is reasonably reproduced by HartreeFock (HF) plus random phase approximation (RPA) calculations that include the Skyrme interaction with tensor components [C. L. Bai et al., Phys. Rev. C 83, 054316 (2011)].  [Show abstract] [Hide abstract]
ABSTRACT: We report measurements of cross sections and analyzing powers for reaction angles of θlab=0.0∘–10.0∘ and complete sets of polarization transfer observables and induced polarizations at θlab=0.0∘–7.0∘ for the 208Pb(p⃗,n⃗) reaction at a bombarding energy of Tp=296 MeV. A multipole decomposition technique was applied to the data to extract the GamowTeller (GT) and spindipole (SD) components from the continuum. The polarization observables were also used, for the first time, to separate the SD components into different spinparity transfer (ΔJπ=0−, 1−, and 2−) contributions. A significant strength with ΔJπ=1+ is identified in the continuum beyond the GT giant resonance, which is due to configuration mixing effects and the isovector spin monopole (IVSM) contribution. The SD strength distributions were clearly dependent on ΔJπ, which is reasonably reproduced by HartreeFock (HF) plus random phase approximation (RPA) calculations that include the Skyrme interaction with tensor components [ Phys. Rev. C 83 054316 (2011)].  [Show abstract] [Hide abstract]
ABSTRACT: We measured pd breakup cross section at E d = 19 MeV (E/A = 9.5 MeV) at Star configuration at 120° ≤ inclination angle α ≤ 180°, i.e. apart from Space Star configuration (α = 90°), and found that pd Star cross section at 120° ≤ α ≤ 180° agree with pd calculation, contrary to Köln data. By our systematic experiments on Star configurations so far and recent reliable pd calculations, existence of Space Star anomaly has been established in pd breakup at E/A = 9.5 and 13 MeV. Also it has been confirmed that no anomaly exist at Star configurations apart from Space Star.  [Show abstract] [Hide abstract]
ABSTRACT: Cross sections of pd breakup reaction at E p = 250 MeV were measured systematically in singleproton detection and in twoproton coincidence detection. Measured cross section is up to two times higher than calculated ones. The enhancement of breakup cross section is similar to reported enhancement in pd elastic scattering cross section. Origins of this enhancement are discussed.  [Show abstract] [Hide abstract]
ABSTRACT: Space Star anomaly in Nd breakup reaction below 20 MeV is wellknown. Also, QuasiFree Scattering (QFS) anomaly in Nd breakup reaction below 40 MeV has been reported from several experiments. Origin(s) of QFS anomaly has not been known, similarly to origin(s) of SS anomaly. We have been making a systematic measurement on ppQFS cross section, previously at E p = 9.5 MeV and 13 MeV and recently at 7.5 and 19 MeV. We used an unpolarized pbeam to correctly measure only cross section. Our data agreed well with pd calculation by A. Deltuva. So far, no ppQFS anomaly has been found in our experiments.  [Show abstract] [Hide abstract]
ABSTRACT: In our previous inclusive experiment on 2H(p, p)pn at 247MeV, the measured cross section at forward angles is about twice larger than 3N calculation with ππ 3NF. Therefore, we have made an exclusive experiment on 2H(p, p 1 p 2)n at the same energy. The preliminary data suggest that the cross section was enhanced at forward angle of θ 1 and θ 2.  [Show abstract] [Hide abstract]
ABSTRACT: Cross section of pd breakup at Star configuration (equilateral triangle) was systematically measured at E = 9.5 and 13 MeV/A with varying an angle α between the Star plane and the beam axis. At 13 MeV/A, Star anomaly appears only around Space Star (α = 90°) configuration. At 9.5 MeV/A, same feature was found in our experimental data at α = 0°−105°, but large difference of about −25% at α = 124°−180° was reported by Köln group.  [Show abstract] [Hide abstract]
ABSTRACT: Space Star (SS) anomaly in Nd breakup cross section is well known. SS anomaly has large charge asymmetry; exp eriment is larger than calculation at nd SS and exp eriment is smaller than calculation at pd SS. There are also rep orts on anomaly in quasifree scattering (QFS) cross section in Nd breakup reaction. At nd QFS, exp erimental cross section was found to be larger than calculation. On the contrary, pd QFS cross section measured by Köln group is smaller than pd calculation. We measured QFS cross section in pd breakup reaction, and compared the data with recent pd calculations to see angular dep endence of QFS anomaly.  [Show abstract] [Hide abstract]
ABSTRACT: In our previous inclusive experiment on pd breakup at Ep = 247 MeV, we found experimental cross section is about twice larger than 3N calculation with ππ3NF at forward angle. Therefore we made exclusive measurement of 2H(p, p1 p2)n cross section at the same 247 MeV. Preliminary data indicate that the cross section enhancement appears at forward angles of θ1 and θ2. We made also inclusive experiment again and conﬁrmed the previous data.  [Show abstract] [Hide abstract]
ABSTRACT: Spacestar anomaly in Nd breakup cross section is well known. There were reports on anomaly in quasifree scattering (QFS) cross section in nd breakup reaction. We measured QFS cross section in pd breakup reaction, and compared the data with recent pd calculations. It was found that experimental QFS cross sections in nd/pd breakup reaction are higher/lower than calculations, respectively.  [Show abstract] [Hide abstract]
ABSTRACT: Up to a few times enhancement of pd breakup cross section was found in our inclusive experiment of ^2H(p,p1)pn at Ep= 250 MeV. The enhancement around Ep1= 150 MeV has been investigated in our exclusive experiment ^2H(p,p1p2)n at the same incident energy in the range of theta2= 35^o80^o. We found that the exclusive cross section enhancement depend on theta2. Enhancement of pd elastic scattering cross section has been found also at the incident energy.  [Show abstract] [Hide abstract]
ABSTRACT: Exclusive measurement of nucleon quasifree scattering is a direct tool to investigate how nucleonnucleon (NN) interaction changes in the nuclear medium. We measured analyzing powers (Ay) for 1s1/2knockout (p,pn) reactions on light nuclei aiming at studying such modification. The experiment was performed at RCNP with a 392 MeV proton beam. It is found that the ^12C(p,pn) exclusive Ay data are mostly consistent with impulse calculations based on the pn interaction in free space, in contrast to the (p,2p) case, where a strong suppression of Ay is observed. This large imbalance between the (p,pn) and (p,2p) results is difficult to explain in conventional models.  [Show abstract] [Hide abstract]
ABSTRACT: In 3nucleon breakup around 10 MeV, there is cross section anomaly when three outgoing nucleons form an equilateral triangle (star configuration) perpendicular to the beam axis. We have measured pd breakup cross section at various star configurations which are inclined to the beam axis, and compared the data with recent pd breakup calculations. Angular dependence and energy dependence of star anomaly will be discussed. 
Article: Measurement of
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18  Citations  
8.34  Total Impact Points  
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Institutions

20102014

Kyushu University
 Department of Physics
Hukuoka, Fukuoka, Japan
