S. Michimasa

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Reaction cross sections (sigma(R)) for 19C, 20C and the drip-line nucleus 22C on a liquid hydrogen target have been measured at around 40A MeV by a transmission method. A large enhancement of sigma(R) for 22C compared to those for neighboring C isotopes was observed. Using a finite-range Glauber calculation under an optical-limit approximation the rms(More)
Atomic nuclei are finite quantum systems composed of two distinct types of fermion--protons and neutrons. In a manner similar to that of electrons orbiting in an atom, protons and neutrons in a nucleus form shell structures. In the case of stable, naturally occurring nuclei, large energy gaps exist between shells that fill completely when the proton or(More)
An excited state in the proton-rich unbound nucleus 12O was identified at 1.8(4) MeV via missing-mass spectroscopy with the 14O(p,t) reaction at 51 AMeV. The spin-parity of the state was determined to be 0+ or 2+ by comparing the measured differential cross sections with distorted-wave calculations. The lowered location of the excited state in 12O indicates(More)
Neutron-rich N=22, 24, 26 magnesium isotopes were studied via in-beam γ-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory following secondary fragmentation reactions on a carbon target at ≈200 MeV/nucleon. In the one- and two-proton removal channels from 39Al and 40Si beams, two distinct γ-ray transitions were observed in 38Mg, while in the(More)
H. L. Crawford,1,* P. Fallon,1 A. O. Macchiavelli,1 R. M. Clark,1 B. A. Brown,2 J. A. Tostevin,2,3 D. Bazin,2 N. Aoi,4 P. Doornenbal,4 M. Matsushita,4 H. Scheit,4 D. Steppenbeck,4 S. Takeuchi,4 H. Baba,4 C. M. Campbell,1 M. Cromaz,1 E. Ideguchi,5 N. Kobayashi,6 Y. Kondo,6 G. Lee,6 I. Y. Lee,1 J. Lee,4 K. Li,4 S. Michimasa,5 T. Motobayashi,4 T. Nakamura,6 S.(More)
The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+))(More)
A. Ozawa,1 Y. Hashizume,1 Y. Aoki,2 K. Tanaka,2 T. Aiba,3 N. Aoi,2 H. Baba,2 B. A. Brown,4 M. Fukuda,5 K. Inafuku,6 N. Iwasa,6 T. Izumikawa,7 K. Kobayashi,8 M. Komuro,8 Y. Kondo,9 T. Kubo,2 M. Kurokawa,2 T. Matsuyama,3 S. Michimasa,10 T. Motobayashi,2 T. Nakabayashi,9 S. Nakajima,8 T. Nakamura,9 T. Ohtsubo,3 H. Sakurai,2 R. Shinoda,8 M. Shinohara,9 H.(More)
Z. Patel, P.-A. Söderström, Zs. Podolyák, P. H. Regan, P. M.Walker, H.Watanabe, E. Ideguchi, G. S. Simpson, H. L. Liu, S. Nishimura, Q. Wu, F. R. Xu, F. Browne, P. Doornenbal, G. Lorusso, S. Rice, L. Sinclair, T. Sumikama, J. Wu, Z. Y. Xu, N. Aoi, H. Baba, F. L. Bello Garrote, G. Benzoni, R. Daido, Y. Fang, N. Fukuda, G. Gey, S. Go, A. Gottardo, N. Inabe,(More)
A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186  MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst)  MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be)(More)
H. Liu1,2, J. Lee2, P. Doornenbal2, H. Scheit1,2, S. Takeuchi2, N. Aoi2, K. Li1,2, M. Matsushita2,3, D. Steppenbeck2, H. Wang2, H. Baba2, E. Ideguchi4, N. Kobayashi5, Y. Kondo5, G. Lee5, S. Michimasa4, T. Motobayashi2, H. Sakurai2, M. Takechi2, Y. Togano2, J.A. Tostevin6 and Y. Utsuno7 1School of Physics and State Key Laboratory of Nuclear Physics and(More)