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2. Experimental signature of medium modifications for rho and omega mesons in the 12 GeV p+A reactions

Author

Naruki, M., Funahashi, H., Fukao, Y., Kitaguchi, M., Ishino, M., Kanda, H., Mihara, S., Miyashita, T., Miwa, K., Murakami, T., Nakura, T., Sakuma, F., Togawa, M., Yamada, S., Yoshimura, Y., En'yo, H., Muto, R., Tabaru, T., Yokkaichi, S., Chiba, J., Ieiri, M., Sasaki, O., Sekimoto, M., Tanaka, K. H., Ozawa, K., and Hamagaki, H.

Subjects
Nuclear Theory, FOS: Physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The invariant mass spectra of e+e- pairs produced in 12-GeV proton-induced nuclear reactions are measured at the KEK Proton-Synchrotron. On the low-mass side of the omega meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted., 4 pages, 3 figures, Version accepted for Physical Review Letter

Published
2005

3. Search for theΘ+Pentaquark via theπ−p→K−XReaction at1.92GeV/c

Author

Shirotori, K., primary, Takahashi, T. N., additional, Adachi, S., additional, Agnello, M., additional, Ajimura, S., additional, Aoki, K., additional, Bhang, H. C., additional, Bassalleck, B., additional, Botta, E., additional, Bufalino, S., additional, Chiga, N., additional, Evtoukhovitch, P., additional, Feliciello, A., additional, Fujioka, H., additional, Hiruma, F., additional, Honda, R., additional, Hosomi, K., additional, Ichikawa, Y., additional, Ieiri, M., additional, Igarashi, Y., additional, Imai, K., additional, Ishibashi, N., additional, Ishimoto, S., additional, Itahashi, K., additional, Iwasaki, R., additional, Joo, C. W., additional, Kim, M. J., additional, Kim, S. J., additional, Kiuchi, R., additional, Koike, T., additional, Komatsu, Y., additional, Kulikov, V. V., additional, Marcello, S., additional, Masumoto, S., additional, Matsuoka, K., additional, Miwa, K., additional, Moritsu, M., additional, Nagae, T., additional, Naruki, M., additional, Niiyama, M., additional, Noumi, H., additional, Ozawa, K., additional, Saito, N., additional, Sakaguchi, A., additional, Sako, H., additional, Samoilov, V., additional, Sato, M., additional, Sato, S., additional, Sato, Y., additional, Sawada, S., additional, Sekimoto, M., additional, Sugimura, H., additional, Suzuki, S., additional, Takahashi, H., additional, Takahashi, T., additional, Tamura, H., additional, Tanaka, T., additional, Tanida, K., additional, Tokiyasu, A. O., additional, Tomida, N., additional, Tsamalaidze, Z., additional, Ukai, M., additional, Yagi, K., additional, Yamamoto, T. O., additional, Yang, S. B., additional, Yonemoto, Y., additional, Yoon, C. J., additional, and Yoshida, K., additional

Published
2012
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4. Evidence for In-Medium Modification of theϕMeson at Normal Nuclear Density

Author

Muto, R., primary, Chiba, J., additional, En’yo, H., additional, Fukao, Y., additional, Funahashi, H., additional, Hamagaki, H., additional, Ieiri, M., additional, Ishino, M., additional, Kanda, H., additional, Kitaguchi, M., additional, Mihara, S., additional, Miwa, K., additional, Miyashita, T., additional, Murakami, T., additional, Nakura, T., additional, Naruki, M., additional, Ozawa, K., additional, Sakuma, F., additional, Sasaki, O., additional, Sekimoto, M., additional, Tabaru, T., additional, Tanaka, K. H., additional, Togawa, M., additional, Yamada, S., additional, Yokkaichi, S., additional, and Yoshimura, Y., additional

Published
2007
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5. Experimental Signature of Medium Modifications forρandωMesons in the 12 GeVp+AReactions

Author

Naruki, M., primary, Fukao, Y., additional, Funahashi, H., additional, Ishino, M., additional, Kanda, H., additional, Kitaguchi, M., additional, Mihara, S., additional, Miwa, K., additional, Miyashita, T., additional, Murakami, T., additional, Nakura, T., additional, Sakuma, F., additional, Togawa, M., additional, Yamada, S., additional, Yoshimura, Y., additional, En’yo, H., additional, Muto, R., additional, Tabaru, T., additional, Yokkaichi, S., additional, Chiba, J., additional, Ieiri, M., additional, Sasaki, O., additional, Sekimoto, M., additional, Tanaka, K. H., additional, Hamagaki, H., additional, and Ozawa, K., additional

Published
2006
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6. Near-Threshold Diffractiveϕ-Meson Photoproduction from the Proton

Author

Mibe, T., primary, Chang, W. C., additional, Nakano, T., additional, Ahn, D. S., additional, Ahn, J. K., additional, Akimune, H., additional, Asano, Y., additional, Daté, S., additional, Ejiri, H., additional, Fujimura, H., additional, Fujiwara, M., additional, Hicks, K., additional, Hotta, T., additional, Imai, K., additional, Ishikawa, T., additional, Iwata, T., additional, Kawai, H., additional, Kim, Z. Y., additional, Kino, K., additional, Kohri, H., additional, Kumagai, N., additional, Makino, S., additional, Matsuda, T., additional, Matsumura, T., additional, Matsuoka, N., additional, Miwa, K., additional, Miyabe, M., additional, Miyachi, Y., additional, Morita, M., additional, Muramatsu, N., additional, Niiyama, M., additional, Nomachi, M., additional, Ohashi, Y., additional, Ooba, T., additional, Ohkuma, H., additional, Oshuev, D. S., additional, Rangacharyulu, C., additional, Sakaguchi, A., additional, Sasaki, T., additional, Shagin, P. M., additional, Shiino, Y., additional, Shimizu, H., additional, Sugaya, Y., additional, Sumihama, M., additional, Titov, A. I., additional, Toi, Y., additional, Toyokawa, H., additional, Wakai, A., additional, Wang, C. W., additional, Wang, S. C., additional, Yonehara, K., additional, Yorita, T., additional, Yoshimura, M., additional, Yosoi, M., additional, and Zegers, R. G. T., additional

Published
2005
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7. Production of the Neutron-Rich HypernucleusLiΛ10in the(π−,K+)Double Charge-Exchange Reaction

Author

Saha, P. K., primary, Fukuda, T., additional, Imoto, W., additional, Ahn, J. K., additional, Ajimura, S., additional, Aoki, K., additional, Bhang, H. C., additional, Fujioka, H., additional, Hotchi, H., additional, Hwang, J. I., additional, Itabashi, T., additional, Kang, B. H., additional, Kim, H. D., additional, Kim, M. J., additional, Kishimoto, T., additional, Krutenkova, A., additional, Maruta, T., additional, Miura, Y., additional, Miwa, K., additional, Nagae, T., additional, Noumi, H., additional, Outa, H., additional, Ohtaki, T., additional, Sakaguchi, A., additional, Sato, Y., additional, Sekimoto, M., additional, Shimizu, Y., additional, Tamura, H., additional, Tanida, K., additional, Toyoda, A., additional, Ukai, M., additional, and Yim, H. J., additional

Published
2005
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8. Beam-Polarization Asymmetries for thep(γ→,K+)Λandp(γ→,K+)Σ0Reactions forEγ=1.5–2.4GeV

Author

Zegers, R. G. T., primary, Sumihama, M., additional, Ahn, D. S., additional, Ahn, J. K., additional, Akimune, H., additional, Asano, Y., additional, Chang, W. C., additional, Daté, S., additional, Ejiri, H., additional, Fujimura, H., additional, Fujiwara, M., additional, Hicks, K., additional, Hotta, T., additional, Imai, K., additional, Ishikawa, T., additional, Iwata, T., additional, Kawai, H., additional, Kim, Z. Y., additional, Kino, K., additional, Kohri, H., additional, Kumagai, N., additional, Makino, S., additional, Matsumura, T., additional, Matsuoka, N., additional, Mibe, T., additional, Miwa, K., additional, Miyabe, M., additional, Miyachi, Y., additional, Morita, M., additional, Muramatsu, N., additional, Nakano, T., additional, Niiyama, M., additional, Nomachi, M., additional, Ohashi, Y., additional, Ooba, T., additional, Ohkuma, H., additional, Oshuev, D. S., additional, Rangacharyulu, C., additional, Sakaguchi, A., additional, Sasaki, T., additional, Shagin, P. M., additional, Shiino, Y., additional, Shimizu, H., additional, Sugaya, Y., additional, Toyokawa, H., additional, Wakai, A., additional, Wang, C. W., additional, Wang, S. C., additional, Yonehara, K., additional, Yorita, T., additional, Yoshimura, M., additional, and Yosoi, M., additional

Published
2003
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9. Evidence for a NarrowS=+1Baryon Resonance in Photoproduction from the Neutron

Author

Nakano, T., primary, Ahn, D. S., additional, Ahn, J. K., additional, Akimune, H., additional, Asano, Y., additional, Chang, W. C., additional, Daté, S., additional, Ejiri, H., additional, Fujimura, H., additional, Fujiwara, M., additional, Hicks, K., additional, Hotta, T., additional, Imai, K., additional, Ishikawa, T., additional, Iwata, T., additional, Kawai, H., additional, Kim, Z. Y., additional, Kino, K., additional, Kohri, H., additional, Kumagai, N., additional, Makino, S., additional, Matsumura, T., additional, Matsuoka, N., additional, Mibe, T., additional, Miwa, K., additional, Miyabe, M., additional, Miyachi, Y., additional, Morita, M., additional, Muramatsu, N., additional, Niiyama, M., additional, Nomachi, M., additional, Ohashi, Y., additional, Ooba, T., additional, Ohkuma, H., additional, Oshuev, D. S., additional, Rangacharyulu, C., additional, Sakaguchi, A., additional, Sasaki, T., additional, Shagin, P. M., additional, Shiino, Y., additional, Shimizu, H., additional, Sugaya, Y., additional, Sumihama, M., additional, Toyokawa, H., additional, Wakai, A., additional, Wang, C. W., additional, Wang, S. C., additional, Yonehara, K., additional, Yorita, T., additional, Yoshimura, M., additional, Yosoi, M., additional, and Zegers, R. G. T., additional

Published
2003
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11. Precise Measurement of Differential Cross Sections of the Σ-p→Λn Reaction in Momentum Range 470-650 MeV/c.

Author

Miwa, K.

Subjects
*DIFFERENTIAL cross sections, *STATISTICAL errors, *ELASTIC scattering
Abstract

The differential cross sections of the Σ-p→Λn reaction were measured accurately for the Σ-momentum (pΣ) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the Σ-p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst) mb for 470

Published
2022
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12. Observation of Coulomb-Assisted Nuclear Bound State of Ξ − – N 14 System

Author

Hayakawa, S. H., Agari, K., Ahn, J. K., Akaishi, T., Akazawa, Y., Ashikaga, S., Bassalleck, B., Bleser, S., Ekawa, H., Endo, Y., Fujikawa, Y., Fujioka, N., Fujita, M., Goto, R., Han, Y., Hasegawa, S., Hashimoto, T., Hayakawa, T., Hayata, E., Hicks, K., Hirose, E., Hirose, M., Honda, R., Hoshino, K., Hoshino, S., Hosomi, K., Hwang, S. H., Ichikawa, Y., Ichikawa, M., Imai, K., Inaba, K., Ishikawa, Y., Ito, H., Ito, K., Jung, W. S., Kanatsuki, S., Kanauchi, H., Kasagi, A., Kawai, T., Kim, M. H., Kim, S. H., Kinbara, S., Kiuchi, R., Kobayashi, H., Kobayashi, K., Koike, T., Koshikawa, A., Lee, J. Y., Ma, T. L., Matsumoto, S. Y., Minakawa, M., Miwa, K., Moe, A. T., Moon, T. J., Moritsu, M., Nagase, Y., Nakada, Y., Nakagawa, M., Nakashima, D., Nakazawa, K., Nanamura, T., Naruki, M., Nyaw, A. N. L., Ogura, Y., Ohashi, M., Oue, K., Ozawa, S., Pochodzalla, J., Ryu, S. Y., Sako, H., Sato, S., Sato, Y., Schupp, F., Shirotori, K., Soe, M. M., Soe, M. K., Sohn, J. Y., Sugimura, H., Suzuki, K. N., Takahashi, H., Takahashi, T., Takeda, T., Tamura, H., Tanida, K., Theint, A. M. M., Tint, K. T., Toyama, Y., Ukai, M., Umezaki, E., Watabe, T., Watanabe, K., Yamamoto, T. O., Yang, S. B., Yoon, C. S., Yoshida, J., Yoshimoto, M., Zhang, D. H., and Zhang, Z.

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13. Observation of Coulomb-Assisted Nuclear Bound State of Ξ^{-}-^{14}N System.

Author

Hayakawa SH, Agari K, Ahn JK, Akaishi T, Akazawa Y, Ashikaga S, Bassalleck B, Bleser S, Ekawa H, Endo Y, Fujikawa Y, Fujioka N, Fujita M, Goto R, Han Y, Hasegawa S, Hashimoto T, Hayakawa T, Hayata E, Hicks K, Hirose E, Hirose M, Honda R, Hoshino K, Hoshino S, Hosomi K, Hwang SH, Ichikawa Y, Ichikawa M, Imai K, Inaba K, Ishikawa Y, Ito H, Ito K, Jung WS, Kanatsuki S, Kanauchi H, Kasagi A, Kawai T, Kim MH, Kim SH, Kinbara S, Kiuchi R, Kobayashi H, Kobayashi K, Koike T, Koshikawa A, Lee JY, Ma TL, Matsumoto SY, Minakawa M, Miwa K, Moe AT, Moon TJ, Moritsu M, Nagase Y, Nakada Y, Nakagawa M, Nakashima D, Nakazawa K, Nanamura T, Naruki M, Nyaw ANL, Ogura Y, Ohashi M, Oue K, Ozawa S, Pochodzalla J, Ryu SY, Sako H, Sato S, Sato Y, Schupp F, Shirotori K, Soe MM, Soe MK, Sohn JY, Sugimura H, Suzuki KN, Takahashi H, Takahashi T, Takeda T, Tamura H, Tanida K, Theint AMM, Tint KT, Toyama Y, Ukai M, Umezaki E, Watabe T, Watanabe K, Yamamoto TO, Yang SB, Yoon CS, Yoshida J, Yoshimoto M, Zhang DH, and Zhang Z

Abstract

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21  MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Published
2021
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14. First Determination of the Level Structure of an sd-Shell Hypernucleus, _{Λ}^{19}F.

Author

Yang SB, Ahn JK, Akazawa Y, Aoki K, Chiga N, Ekawa H, Evtoukhovitch P, Feliciello A, Fujita M, Hasegawa S, Hayakawa S, Hayakawa T, Honda R, Hosomi K, Hwang SH, Ichige N, Ichikawa Y, Ikeda M, Imai K, Ishimoto S, Kanatsuki S, Kim SH, Kinbara S, Kobayashi K, Koike T, Lee JY, Miwa K, Moon TJ, Nagae T, Nakada Y, Nakagawa M, Ogura Y, Sakaguchi A, Sako H, Sasaki Y, Sato S, Shirotori K, Sugimura H, Suto S, Suzuki S, Takahashi T, Tamura H, Tanida K, Togawa Y, Tsamalaidze Z, Ukai M, Wang TF, and Yamamoto TO

Abstract

We report on the first observation of γ rays emitted from an sd-shell hypernucleus, _{Λ}^{19}F. The energy spacing between the ground state doublet, 1/2^{+} and 3/2^{+} states, of _{Λ}^{19}F is determined to be 315.5±0.4(stat)_{-0.5}^{+0.6}(syst)  keV by measuring the γ-ray energy of the M1(3/2^{+}→1/2^{+}) transition. In addition, three γ-ray peaks are observed and assigned as E2(5/2^{+}→1/2^{+}), E1(1/2^{-}→1/2^{+}), and E1(1/2^{-}→3/2^{+}) transitions. The excitation energies of the 5/2^{+} and 1/2^{-} states are determined to be 895.2±0.3(stat)±0.5(syst) and 1265.6±1.2(stat)_{-0.5}^{+0.7}(syst)  keV, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing s- and p-shell hypernuclear data.

Published
2018
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15. Single-Molecule Investigation of Energy Dynamics in a Coupled Plasmon-Exciton System.

Author

Imada H, Miwa K, Imai-Imada M, Kawahara S, Kimura K, and Kim Y

Abstract

We investigate the near-field interaction between an isolated free-base phthalocyanine molecule and a plasmon localized in the gap between an NaCl-covered Ag(111) surface and the tip apex of a scanning tunneling microscope. When the tip is located in the close proximity of the molecule, asymmetric dips emerge in the broad luminescence spectrum of the plasmon generated by the tunneling current. The origin of the dips is explained by energy transfer between the plasmon and molecular excitons and a quantum mechanical interference effect, where molecular vibrations provide additional degrees of freedom in the dynamic process.

Published
2017
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16. Observation of Spin-Dependent Charge Symmetry Breaking in ΛN Interaction: Gamma-Ray Spectroscopy of _{Λ}^{4}He.

Author

Yamamoto TO, Agnello M, Akazawa Y, Amano N, Aoki K, Botta E, Chiga N, Ekawa H, Evtoukhovitch P, Feliciello A, Fujita M, Gogami T, Hasegawa S, Hayakawa SH, Hayakawa T, Honda R, Hosomi K, Hwang SH, Ichige N, Ichikawa Y, Ikeda M, Imai K, Ishimoto S, Kanatsuki S, Kim MH, Kim SH, Kinbara S, Koike T, Lee JY, Marcello S, Miwa K, Moon T, Nagae T, Nagao S, Nakada Y, Nakagawa M, Ogura Y, Sakaguchi A, Sako H, Sasaki Y, Sato S, Shiozaki T, Shirotori K, Sugimura H, Suto S, Suzuki S, Takahashi T, Tamura H, Tanabe K, Tanida K, Tsamalaidze Z, Ukai M, Yamamoto Y, and Yang SB

Abstract

The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2  keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

Published
2015
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17. Search for the Θ+ pentaquark via the π(-)p→K(-)X reaction at 1.92 GeV/c.

Author

Shirotori K, Takahashi TN, Adachi S, Agnello M, Ajimura S, Aoki K, Bhang HC, Bassalleck B, Botta E, Bufalino S, Chiga N, Evtoukhovitch P, Feliciello A, Fujioka H, Hiruma F, Honda R, Hosomi K, Ichikawa Y, Ieiri M, Igarashi Y, Imai K, Ishibashi N, Ishimoto S, Itahashi K, Iwasaki R, Joo CW, Kim MJ, Kim SJ, Kiuchi R, Koike T, Komatsu Y, Kulikov VV, Marcello S, Masumoto S, Matsuoka K, Miwa K, Moritsu M, Nagae T, Naruki M, Niiyama M, Noumi H, Ozawa K, Saito N, Sakaguchi A, Sako H, Samoilov V, Sato M, Sato S, Sato Y, Sawada S, Sekimoto M, Sugimura H, Suzuki S, Takahashi H, Takahashi T, Tamura H, Tanaka T, Tanida K, Tokiyasu AO, Tomida N, Tsamalaidze Z, Ukai M, Yagi K, Yamamoto TO, Yang SB, Yonemoto Y, Yoon CJ, and Yoshida K

Abstract

The Θ(+) pentaquark baryon was searched for via the π(-)p→K(-)X reaction with a missing mass resolution of 1.4 MeV/c(2) (FWHM) at the Japan Proton Accelerator Research Complex (J-PARC). π(-) meson beams were incident on the liquid hydrogen target with a beam momentum of 1.92 GeV/c. No peak structure corresponding to the Θ(+) mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2° to 15° in the laboratory frame is obtained to be 0.26 μb/sr in the mass region of 1.51-1.55 GeV/c(2). The upper limit of the Θ(+) decay width is obtained to be 0.72 and 3.1 MeV for J(Θ)(P)=1/2(+) and J(Θ)(P)=1/2(-), respectively, using the effective Lagrangian approach.

Published
2012
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18. Nuclear-matter modification of decay widths in the phi-->e+e- and phi-->K+K- channels.

Author

Sakuma F, Chiba J, En'yo H, Fukao Y, Funahashi H, Hamagaki H, Ieiri M, Ishino M, Kanda H, Kitaguchi M, Mihara S, Miwa K, Miyashita T, Murakami T, Muto R, Nakura T, Naruki M, Ozawa K, Sasaki O, Sekimoto M, Tabaru T, Tanaka KH, Togawa M, Yamada S, Yokkaichi S, and Yoshimura Y

Abstract

The invariant mass spectra of phi-->K+K- are measured in 12 GeV p+A reactions in order to search for the in-medium modification of phi mesons. The observed K+K- spectra are well reproduced by the relativistic Breit-Wigner function with a combinatorial background shape in three betagamma regions between 1.0 and 3.5. The nuclear mass number dependence of the yields of the K+K- decay channel is compared to the simultaneously measured e+e- decay channel for carbon and copper targets. We parameterize the production yields as sigma(A)=sigma0Aalpha and obtain alphaphi-->K+K- -alphaphi-->e+e- to be 0.14+/-0.12. Limits are obtained for the partial decay widths of the phi mesons in nuclear matter.

Published
2007
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19. Evidence for in-medium modification of the phi meson at normal nuclear density.

Author

Muto R, Chiba J, En'yo H, Fukao Y, Funahashi H, Hamagaki H, Ieiri M, Ishino M, Kanda H, Kitaguchi M, Mihara S, Miwa K, Miyashita T, Murakami T, Nakura T, Naruki M, Ozawa K, Sakuma F, Sasaki O, Sekimoto M, Tabaru T, Tanaka KH, Togawa M, Yamada S, Yokkaichi S, and Yoshimura Y

Abstract

Invariant mass spectra of e(+) e(-) pairs have been measured in 12 GeV p + A reactions to detect possible in-medium modification of vector mesons. Copper and carbon targets are used to study the nuclear-size dependence of e(+) e(-) invariant mass distributions. A significant excess on the low-mass side of the phi meson peak is observed in the low betagamma(= beta/square root(1-beta(2))) region of phi mesons (betagamma < 1.25) with copper targets. However, in the high betagamma region (betagamma > 1.25), spectral shapes of phi mesons are well described by the Breit-Wigner shape when experimental effects are considered. Thus, in addition to our earlier publications on rho/omega modification, this study has experimentally verified vector meson mass modification at normal nuclear density.

Published
2007
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20. Experimental signature of medium modifications for rho and omega mesons in the 12 GeV p+A reactions.

Author

Naruki M, Fukao Y, Funahashi H, Ishino M, Kanda H, Kitaguchi M, Mihara S, Miwa K, Miyashita T, Murakami T, Nakura T, Sakuma F, Togawa M, Yamada S, Yoshimura Y, En'yo H, Muto R, Tabaru T, Yokkaichi S, Chiba J, Ieiri M, Sasaki O, Sekimoto M, Tanaka KH, Hamagaki H, and Ozawa K

Abstract

The invariant mass spectra of e+e- pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.

Published
2006
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21. Near-threshold diffractive psi-meson photoproduction from the proton.

Author

Mibe T, Chang WC, Nakano T, Ahn DS, Ahn JK, Akimune H, Asano Y, Daté S, Ejiri H, Fujimura H, Fujiwara M, Hicks K, Hotta T, Imai K, Ishikawa T, Iwata T, Kawai H, Kim ZY, Kino K, Kohri H, Kumagai N, Makino S, Matsuda T, Matsumura T, Matsuoka N, Miwa K, Miyabe M, Miyachi Y, Morita M, Muramatsu N, Niiyama M, Nomachi M, Ohashi Y, Ooba T, Ohkuma H, Oshuev DS, Rangacharyulu C, Sakaguchi A, Sasaki T, Shagin PM, Shiino Y, Shimizu H, Sugaya Y, Sumihama M, Titov AI, Toi Y, Toyokawa H, Wakai A, Wang CW, Wang SC, Yonehara K, Yorita T, Yoshimura M, Yosoi M, and Zegers RG

Abstract

Photoproduction of a phi meson on protons was studied by means of linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections at t = -|t|min do not increase smoothly as Egamma increases but show a local maximum at around 2.0 GeV. The angular distributions demonstrate that phi mesons are photoproduced predominantly by helicity-conserving processes, and the local maximum is not likely due to unnatural-parity processes.

Published
2005
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22. Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction.

Author

Saha PK, Fukuda T, Imoto W, Ahn JK, Ajimura S, Aoki K, Bhang HC, Fujioka H, Hotchi H, Hwang JI, Itabashi T, Kang BH, Kim HD, Kim MJ, Kishimoto T, Krutenkova A, Maruta T, Miura Y, Miwa K, Nagae T, Noumi H, Outa H, Ohtaki T, Sakaguchi A, Sato Y, Sekimoto M, Shimizu Y, Tamura H, Tanida K, Toyoda A, Ukai M, and Yim HJ

Abstract

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.

Published
2005
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23. Beam-polarization asymmetries for the p(gamma-->, K+)Lambda and p(gamma-->, K+)Sigma(0) reactions for E(gamma)=1.5-2.4 GeV.

Author

Zegers RG, Sumihama M, Ahn DS, Ahn JK, Akimune H, Asano Y, Chang WC, Daté S, Ejiri H, Fujimura H, Fujiwara M, Hicks K, Hotta T, Imai K, Ishikawa T, Iwata T, Kawai H, Kim ZY, Kino K, Kohri H, Kumagai N, Makino S, Matsumura T, Matsuoka N, Mibe T, Miwa K, Miyabe M, Miyachi Y, Morita M, Muramatsu N, Nakano T, Niiyama M, Nomachi M, Ohashi Y, Ooba T, Ohkuma H, Oshuev DS, Rangacharyulu C, Sakaguchi A, Sasaki T, Shagin PM, Shiino Y, Shimizu H, Sugaya Y, Toyokawa H, Wakai A, Wang CW, Wang SC, Yonehara K, Yorita T, Yoshimura M, and Yosoi M

Abstract

Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured for the first time for E(gamma)=1.5-2.4 GeV and 0.6

Published
2003
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24. Evidence for a narrow S = +1 baryon resonance in photoproduction from the neutron.

Author

Nakano T, Ahn DS, Ahn JK, Akimune H, Asano Y, Chang WC, Daté S, Ejiri H, Fujimura H, Fujiwara M, Hicks K, Hotta T, Imai K, Ishikawa T, Iwata T, Kawai H, Kim ZY, Kino K, Kohri H, Kumagai N, Makino S, Matsumura T, Matsuoka N, Mibe T, Miwa K, Miyabe M, Miyachi Y, Morita M, Muramatsu N, Niiyama M, Nomachi M, Ohashi Y, Ooba T, Ohkuma H, Oshuev DS, Rangacharyulu C, Sakaguchi A, Sasaki T, Shagin PM, Shiino Y, Shimizu H, Sugaya Y, Sumihama M, Toyokawa H, Wakai A, Wang CW, Wang SC, Yonehara K, Yorita T, Yoshimura M, Yosoi M, and Zegers RG

Abstract

The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) and a Gaussian significance of 4.6sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state (uuddsmacr;) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.

Published
2003
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