M Nakamura

Publications (16)4.44 Total impact

• Article: Photoproduction of Λ(1405) and Σ0(1385) on the proton at Eγ=1.5-2.4 GeV

  M. Niiyama, H. Fujimura, D. S. Ahn, J. K. Ahn, S. Ajimura, H. C. Bhang, T. H. Chang, W. C. Chang, J. Y. Chen, S. Daté, [......], J. D. Parker, N. Saito, T. Sawada, Y. Sugaya, M. Sumihama, J. L. Tang, M. Uchida, C. W. Wang, T. Yorita, M. Yosoi
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  ABSTRACT: Differential cross sections for γp→K+Λ(1405) and γp→K+Σ0(1385) reactions have been measured in the photon energy range from 1.5 to 2.4 GeV and the angular range of 0.8<cos(Θ)<1.0 for the K+ scattering angle in the center-of-mass system. This data is the first measurement of the Λ(1405) photoproduction cross section. The line shapes of Λ(1405) measured in Σ+π- and Σ-π+ decay modes were different with each other, indicating a strong interference of the isospin 0 and 1 terms of the Σπ scattering amplitudes. The ratios of Λ(1405) production to Σ0(1385) production were measured in two photon energy ranges: near the production threshold (1.5<Eγ<2.0 GeV) and far from it (2.0<Eγ<2.4 GeV). The observed ratio decreased in the higher photon energy region, which may suggest different production mechanisms and internal structures for these hyperon resonances.
  Physical Review C 09/2008; 78(3):035202. · 3.31 Impact Factor
• Source

  Available from: Schin Date

  Article: Photoproduction of Lambda(1405) and Sigma^{0}(1385) on the proton at E_\gamma = 1.5-2.4 GeV

  M. Niiyama, H Fujimura, D S Ahn, J K Ahn, S. Ajimura, H. C. Bhang, T H Chang, W C Chang, J Y Chen, S. Daté, [......], D. S. Oshuev, N Saito, T Sawada, Y. Sugaya, M. Sumihama, J L Tang, M Uchida, C. W. Wang, T. Yorita, M. Yosoi
  [show abstract] [hide abstract]
  ABSTRACT: Differential cross sections for $\gamma p \to K^+\Lambda(1405)$ and $\gamma p \to K^+\Sigma^0(1385)$ reactions have been measured in the photon energy range from 1.5 to 2.4 GeV and the angular range of $0.8<\cos(\Theta)<1.0$ for the $K^+$ scattering angle in the center-of-mass system. This data is the first measurement of the $\Lambda(1405)$ photoproduction cross section. The lineshapes of \LamS measured in $\Sigma^+\pi^-$ and $\Sigma^-\pi^+$ decay modes were different with each other, indicating a strong interference of the isospin 0 and 1 terms of the $\Sigma\pi$ scattering amplitudes. The ratios of \LamS production to \SigS production were measured in two photon energy ranges: near the production threshold ($1.5<E_\gamma<2.0$ GeV) and far from it ($2.0 <E_\gamma<2.4$ GeV). The observed ratio decreased in the higher photon energy region, which may suggest different production mechanisms and internal structures for these hyperon resonances.
  06/2008;
• Source

  Available from: Harutaka Sakaguchi

  Article: De-excitation gamma-rays from the s-hole state in 15N associated with proton decay in 16O

  K Kobayashi, H. Akimune, H. Ejiri, H Fujimura, M Fujiwara, K Hara, K. Y. Hara, T Ishikawa, M Itoh, Y. Itow, [......], M Shiozawa, H Takeda, Y Totsuka, H. Toyokawa, M Uchida, T Yamada, Y Yasuda, H. P. Yoshida, M. Yosoi, R. G. T. Zegers
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  ABSTRACT: We have measured de-excitation gamma-rays from the s-hole state in 15N produced via the 16O(p,2p)15N reaction in relation to the study of the nucleon decay and the neutrino neutral-current interaction in water Cherenkov detectors. In the excitation-energy region of the s-hole state between 16 MeV and 40 MeV in 15N, the branching ratio of emitting gamma-rays with the energies at more-than-6 MeV are found to be 15.6+-1.3+0.6-1.0%. Taking into account the spectroscopic factor of the s-hole state, the total emission probability is found to be 3.1%. This is about 1/10 compared with the emission probability of the 6.32 MeV gamma-ray from the 3/2- p-hole state in 15N. Moreover, we searched for a 15.1 MeV gamma-ray from the 12C 1+ state which may be populated after the particle-decay of the s-hole state in 15N. Such a high energy gamma-ray from the hole state would provide a new method to search for mode-independent nucleon decay even if the emission probability is small. No significant signal is found within a statistical uncertainty.
  05/2006;
• Source

  Available from: Teruaki Nakano

  Article: phi photo-production from Li, C, Al, and Cu nuclei at Egamma=1.5 - 2.4 GeV

  T Ishikawa, D S Ahn, J K Ahn, H. Akimune, W C Chang, S. Date, H Fujimura, M Fujiwara, K Hicks, T Hotta, [......], Y. Sakemi, H Shimizu, Y. Sugaya, M. Sumihama, Y. Toi, H. Toyokawa, C. W. Wang, T. Yorita, M. Yosoi, R. G. T. Zegers
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  ABSTRACT: The photo-production of $\phi$ mesons from Li, C, Al, and Cu at forward angles has been measured at $E_gamma$=1.5--2.4 GeV. The number of events for incoherent phi photo-production is found to have a target mass number dependence of $A^{0.72\pm 0.07}$ in the kinematical region of $|t|\le 0.6$ ${\rm GeV}^2/c^2$. The total cross section of the $\phi$-nucleon interaction, $\sigma_{\phi N}$, has been estimated as $35^{+17}_{-11}$ mb using the $A$-dependence of the $\phi$ photo-production yield and a Glauber-type multiple scattering theory. This value is much larger than $\sigma_{\phi N}$ in free space, suggesting that the $\phi$ properties might change in the nuclear medium.
  12/2004;
• Source

  Available from: Harutaka Sakaguchi

  Article: Structures and decay of deep-hole states in light nuclei populated by the (p, 2p 2p) reactions

  M. Yosoi, H. Akimune, I. Daito, H. Ejiri, H. Fujimura, M. Fujiwara, K. Hara, K. Y. Hara, T. Ishikawa, M. Itoh, [......], H. Takeda, T. Taki, A. Tamii, H. Toyokawa, N. Tsukahara, M. Uchida, T. Yamada, Y. Yasuda, H. P. Yoshida, R. G. T. Zegers
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  ABSTRACT: Decay particles from the s-hole states in 11B and 15N have been measured in coincidence with the quasifree 12C(p, 2p) and 16O(p, 2p) reactions at E p =392 MeV. Triton decay is found to be dominant for the 11B(s-hole) state and also found to be larger than α decay for the 15N(s-hole) state despite its smaller Q value compared to α decay. Measured decay branching ratios are discussed in comparison with the results of statistical-model, SU(3)-model, and shell-model calculations. The energy spectra around the s-hole states in both 11B and 15N exhibit some bumplike structures, which can be qualitatively explained by recent shell-model calculations for both nuclei.
  Physics of Atomic Nuclei 09/2004; 67(10):1810-1817. · 0.57 Impact Factor
• Source

  Available from: Harutaka Sakaguchi

  Article: Isovector and isoscalar spin-flip M1 strengths in $^{11}$B

  T Kawabata, H. Akimune, H Fujimura, H Fujita, Y Fujita, M Fujiwara, K Hara, K. Y. Hara, K Hatanaka, T Ishikawa, [......], H Takeda, A. Tamii, S Terashima, H. Toyokawa, M Uchida, H Ueno, T. Wakasa, Y Yasuda, H. P. Yoshida, M. Yosoi
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  ABSTRACT: The $^{11}$B($^3$He$, t$), $^{11}$B($d, d'$), and $^{11}$B($p, p'$) reactions were measured at forward scattering angles including $0^\circ$ to study the isovector and isoscalar spin-flip M1 strengths in $^{11}$B. The measured $^{11}$B($^3$He$, t$) cross sections were compared with the results of the distorted-wave impulse-approximation (DWIA) calculation, and the Gamow-Teller (GT) strengths for low-lying states in $^{11}$C were determined. The GT strengths were converted to the isovector spin-flip M1 strengths using the isobaric analog relations under the assumption of the isospin symmetry. The isoscalar spin-flip M1 strengths were obtained from the ($d, d'$) analysis by assuming that the shape of the collective transition form factor with the same ${\Delta}J^\pi$ is similar in the $^{11}$B($d, d'$) and $^{12}$C($d, d'$) reactions. The obtained isovector and isoscalar strengths were used in the DWIA calculations for the $^{11}$B($p, p'$) reaction. The DWIA calculation reasonably well explains the present $^{11}$B($p, p'$) result. However, the calculated cross section for the 8.92-MeV 3/2$^-_2$ state was significantly smaller than the experimental values. The transition strengths obtained in the shell-model calculations were found to be 20-50% larger than the experimental strengths. The transition strengths for the neutrino induced reactions were estimated by using the isovector and isoscalar spin-flip M1 strengths. The present results are quantitatively in agreement with the theoretical estimation discussing the axial isoscalar coupling in the neutrino scattering process, and are useful in the measurement of the stellar neutrinos using the neutral- and charged-current reactions on $^{11}$B.
  06/2004;
• Source

  Available from: osaka-u.ac.jp

  Article: Structures and decay of deep-hole states in light nuclei populated by the (p, 2p 2p) reactions

  M Yosoi, H Akimune, I Daito, H Ejiri, H Fujimura, M Fujiwara, K Hara, K Y Hara, T Ishikawa, M Itoh, [......], M Shiozawa, H Takeda, T Taki, A Tamii, H Toyokawa, N Tsukahara, M Uchida, T Yamada, Y Yasuda, H P Yoshida
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  ABSTRACT: Decay particles from the s-hole states in 11 B and 15 N have been measured in coincidence with the quasifree 12 C(p, 2p) and 16 O(p, 2p) reactions at E p = 392 MeV. Triton decay is found to be dominant for the 11 B(s-hole) state and also found to be larger than α decay for the 15 N(s-hole) state despite its smaller Q value compared to α decay. Measured decay branching ratios are discussed in comparison with the results of statistical-model, SU (3)-model, and shell-model calculations. The energy spectra around the s-hole states in both 11 B and 15 N exhibit some bumplike structures, which can be qualitatively explained by recent shell-model calculations for both nuclei. c 2004 MAIK "Nauka/Interperiodica".
  Physics of Atomic Nuclei 01/2004; 67(67):1810-1817. · 0.57 Impact Factor
• Source

  Available from: Harutaka Sakaguchi

  Article: Polarization transfer in the $^{16}$O$(p,p')$ reaction at forward angles and structure of the spin-dipole resonances

  T Kawabata, H. Akimune, G.P.A. Berg, H Fujimura, H Fujita, Y Fujita, M Fujiwara, K Hara, K Hatanaka, K Hosono, [......], T Taki, A. Tamii, H. Toyokawa, M Uchida, H Ueno, T. Wakasa, K Yamasaki, Y Yasuda, H. P. Yoshida, M. Yosoi
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  ABSTRACT: Cross sections and polarization transfer observables in the $^{16}$O$(p,p')$ reactions at 392 MeV were measured at several angles between $\theta_{lab}=$ 0$^\circ$ and 14$^\circ$. The non-spin-flip (${\Delta}S=0$) and spin-flip (${\Delta}S=1$) strengths in transitions to several discrete states and broad resonances in $^{16}$O were extracted using a model-independent method. The giant resonances in the energy region of $E_x=19-$27 MeV were found to be predominantly excited by ${\Delta}L=1$ transitions. The strength distribution of spin-dipole transitions with ${\Delta}S=1$ and ${\Delta}L=1$ were deduced. The obtained distribution was compared with a recent shell model calculation. Experimental results are reasonably explained by distorted-wave impulse approximation calculations with the shell model wave functions. Comment: 28 pages RevTex, including 9 figures, to be published in Phys. Rev. C.; a typo in Eq. (3b) was corrected
  02/2002;
• Article: Rapid sintering under nitrogen-hydrogen atmosphere on carbon steels using by the induction heating method (report 3)

  M. Nakamura, T. Umemura, T. Ohba, Y. Sugaya, C.-G. Kim
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  ABSTRACT: Cited By (since 1996): 2, Export Date: 13 April 2010, Source: Scopus, CODEN: FOFUA, Language of Original Document: Japanese, Correspondence Address: Nakamura, M.; Fac. Eng., Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan, References: Japanese sourceKrumphold, R., Hernel, W., Leitner, G., (1984) Short-Time Induction Sintering of Fe-Based Materials and Hardmetals, pp. 127-138. , Elsevier Science;
  Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy. 01/2001; 48(7):594-599.
• Article: Rapid sintering under nitrogen atmosphere to carbon steels using by the induction heating method (report 2)

  M. Nakamura, T. Umemura, T. Ohba, Y. Sugaya
  [show abstract] [hide abstract]
  ABSTRACT: Cited By (since 1996): 3, Export Date: 13 April 2010, Source: Scopus, CODEN: FOFUA, Language of Original Document: Japanese, Correspondence Address: Nakamura, M.; Fac. Eng., Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan, References: Japanese sourceKrumphold, R., Hemel, W., Leitner, G., (1984) Short-Time Induction Sintering of Fe-Based Materials and Hardmetals, pp. 127-138. , Elsevier Science;
  Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy. 01/2001; 48(1):87-93.
• Source

  Available from: Harutaka Sakaguchi

  Article: Thin Ice Target for $^{16}$O(p,p') experiment

  T Kawabata, H. Akimune, H Fujimura, H Fujita, Y Fujita, M Fujiwara, K Hara, K Hatanaka, K Hosono, T Ishikawa, [......], A. Tamii, H. Toyokawa, N Tsukahara, M Uchida, H Ueno, T. Wakasa, K Yamasaki, Y Yasuda, H. P. Yoshida, M. Yosoi
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  ABSTRACT: A windowless and self-supporting ice target is described. An ice sheet with a thickness of 29.7 mg/cm$^2$ cooled by liquid nitrogen was placed at the target position of a magnetic spectrometer and worked stably in the $^{16}$O$(p,p')$ experiment at $E_{p}=392$ MeV. Background-free spectra were obtained. Comment: 14 pages, 4 figures, Nucl. Instr. & Meth. A (in press)
  12/2000;
• Article: Development of rapid sintering technique on carbon steels by the induction heating method

  M. Nakamura, N. Chida, T. Ohba, Y. Sugaya
  [show abstract] [hide abstract]
  ABSTRACT: Cited By (since 1996): 3, Export Date: 13 April 2010, Source: Scopus, CODEN: FOFUA, Language of Original Document: Japanese, Correspondence Address: Nakamura, Mitsuru; Iwate Univ, Morioka, Japan, References: Japanese sourceJapanese sourceKrumphold, R., Hernel, W., Leitner, G., Short-time induction sintering of Fe-based materials and hardmetals (1984) Elsevier Science, pp. 127-138;
  Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy. 01/1999; 46(5):538-543.
• Article: Time projection chamber at SPring-8

  M. Niiyama, K. Imai, M. Nakamura, M. Yosoi, T. Ishikawa, M. Miyabe, K. Miwa, J.K. Ahn, D.S. Ahn, T. Nakano, H. Bhang, H. Fujimura, H. Kohri, Y. Sugaya, C.W. Wang, W.C. Chang, T.H. Chang, D. Oshuev
  [show abstract] [hide abstract]
  ABSTRACT: We have constructed a Time Projection Chamber (TPC) as the 4π detector for hadron photoproduction experiments at SPring-8. A feature of this TPC is to detect low momentum hyperons as close as 16 mm from the target center. We have studied basic performances of the TPC such as the resolution of dE/dx measurement and the spatial resolution with cosmic rays. The resolution of dE/dx measurement is 16% for minimum ionizing particles. The spatial resolution in pad plane is 280 μm and that along drift direction is 620 μm. The spatial resolution at the distance of 16 mm from the target is obtained to be 400 μm and 880 μm in pad plane and along drift direction respectively.
  Nuclear Physics A. 721.
• Article: Structure and decay of the s-hole state in 11B studied via the 12C(p,2p)11B∗ reaction

  M Yosoi, H Akimune, I Daito, H Ejiri, H Fujimura, M Fujiwara, T Ishikawa, M Itoh, T Kawabata, M Nakamura, [......], E Obayashi, H Sakaguchi, H Takeda, T Taki, A Tamii, H Toyokawa, N Tsukahara, M Uchida, T Yamada, H.P Yoshida
  [show abstract] [hide abstract]
  ABSTRACT: Charged particle decay of the s-hole state in 11B was measured in coincidence with the quasifree 12C(p,2p) reaction at 392 MeV incident energy. Triton-decay was found to be dominant despite its smaller Q-value than that of α-decay. The measured decay pattern is compared to the results of statistical model and microscopic SU(3)-cluster model calculations. The energy spectrum around the s-hole state exhibits three bump-like structures, which can be qualitatively explained by a recent shell-model calculation.
  Physics Letters B.
• Article: φ Photo-production from Nuclei at E_γ=1.5-2.4 GeV(I. Nuclear Physics)

  T Ishikawa, D S Ahn, J K Ahn, H. Akimune, W C Chang, S. Date, H Fujimura, M Fujiwara, K Hicks, T Hotta, [......], Y. Sakemi, H Shimizu, Y. Sugaya, M. Sumihama, Y. Toi, H. Toyokawa, C. W. Wang, T. Yorita, M. Yosoi, R. G. T. Zegers
• Article: Polarization transfer observables for proton inelastic scattering from 12C at 0°

  A. Tamii, H. Akimune, I. Daito, Y. Fujita, M. Fujiwara, K. Hatanaka, K. Hosono, F. Ihara, T. Inomata, T. Ishikawa, [......], M. Nakamura, T. Noro, E. Obayashi, H. Sakaguchi, H. Takeda, T. Taki, H. Toyokawa, H.P. Yoshida, M. Yoshimura, M. Yosoi
  [show abstract] [hide abstract]
  ABSTRACT: Polarization transfer (PT) observables in the reaction at 0° for 392 MeV protons have been measured. The excitation strengths are decomposed into the spin-flip part and the non-spin-flip part by using the obtained PT observables. The PT observables for excitation of the 1+, T=0 and 1+, T=1 states are compared with distorted wave impulse approximation calculations. The strength ratios of the isoscalar spin-dependent term to the isovector tensor term and the isovector tensor term to the isovector spin-dependent term are reasonably consistent with the Franey and Love interaction.
  Physics Letters B.