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Pohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; Gmez-Ramos, M.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.
Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04
Times Cited Count:5 Percentile:91.26(Physics, Multidisciplinary)We report on the first proton-induced single proton- and neutron-removal reactions from the neutron deficient O nucleus with large Fermi-surface asymmetry at 100 MeV/nucleon. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively.
Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.
Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02
Times Cited Count:45 Percentile:96.73(Physics, Multidisciplinary)A quasifree (,) experiment was performed to study the structure of the Borromean nucleus B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for and orbitals, and a surprisingly small percentage of 9(2)% was determined for . Our finding of such a small component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B. The present work gives the smallest - or -orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of or orbitals is not a prerequisite for the occurrence of a neutron halo.
Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
Times Cited Count:14 Percentile:72.90(Physics, Multidisciplinary)The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
Kawamura, Seiko; Hattori, Takanori; Harjo, S.; Ikeda, Kazutaka*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Watanabe, Masao; Sakaguchi, Yoshifumi*; Oku, Takayuki
Neutron News, 30(1), p.11 - 13, 2019/05
In Japanese neutron scattering facilities, some SE equipment that are frequently used at an instrument, such as the closed-cycle refrigerator (CCR), have been prepared for the instrument as standard SE. They are operated for user experiments by the instrument group. The advantage of this practice is that they can optimize the design of the SE for the instrument and can directly respond to users' requests. On the other hand, the SE team in the Materials and Life Science Experimental Facility (MLF) in J-PARC has managed commonly used SE to allow neutron experiments with more advanced SE. In this report, recent SE in the MLF is introduced. Highlighted are the SE in BL11, BL19, BL21 and BL17 and other SE recently progressed by the SE team.
Sako, Hiroyuki; Harada, Hiroyuki; Sakaguchi, Takao*; Chujo, Tatsuya*; Esumi, Shinichi*; Gunji, Taku*; Hasegawa, Shoichi; Hwang, S.; Ichikawa, Yudai; Imai, Kenichi; et al.
Nuclear Physics A, 956, p.850 - 853, 2016/12
Times Cited Count:13 Percentile:67.64(Physics, Nuclear)Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07
Times Cited Count:29 Percentile:73.10(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry () of jet production in longitudinally polarized collisions at = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured = -0.0014 0.0037 at the lowest bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various distributions.
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count:184 Percentile:99.42(Physics, Nuclear)Transverse momentum distributions and yields for , and in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as and scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count:9 Percentile:52.86(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03
Times Cited Count:177 Percentile:98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of , , and mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, and , determining the high and characterizing the low regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
Endo, Satoru*; Tomita, Jumpei*; Tanaka, Kenichi*; Yamamoto, Masayoshi*; Fukutani, Satoshi*; Imanaka, Tetsuji*; Sakaguchi, Aya*; Amano, Hikaru; Kawamura, Hidehisa*; Kawamura, Hisao*; et al.
Radiation and Environmental Biophysics, 47(3), p.359 - 365, 2008/07
Times Cited Count:5 Percentile:20.95(Biology)Dolon village located about 60 km from the border of the Semipalatinsk Nuclear Test Site is known to be heavily contaminated by the first USSR atomic bomb test in August 1949. Soil samples around Dolon were taken in October 2005 in an attempt to evaluate internal thyroid dose arising from incorporation of radioiodine isotopes (mainly I). Iodine-129 in soil was measured by using the technique of Accelerator Mass Spectrometry. From the relationship between I and Cs (corrected for background and decay from 1949 to 2005) accumulated levels, the background level of I and the I/Cs ratio around Dolon were estimated to be (6.4 0.4) 10 atoms m and 0.25 0.16, respectively. This I/Cs ratio is almost similar to the fission yield ratio for Pu fast fission (0.24).
Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.
Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08
Times Cited Count:128 Percentile:94.86(Physics, Multidisciplinary)no abstracts in English
Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.
Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07
Times Cited Count:1007 Percentile:99.86(Physics, Multidisciplinary)no abstracts in English
Iemura, K.*; Otani, Shunsuke*; Suzuki, H.*; Takeda, Junichi*; Machida, Shuichi*; Tanabe, K.*; Takayanagi, Toshinobu*; Wakiya, K.*; Sekiguchi, M.*; Kanai, Yasuyuki*; et al.
Physical Review A, 64(6), p.062709_1 - 062709_14, 2001/12
Times Cited Count:6 Percentile:35.66(Optics)We measured ejected electron spectra caused by autoionization of doubly excited states in He atoms; the excited He was made by double electron capture of low-energy He ions colliding with Ba atoms. Measurements were performed by means of zero degree electron spectroscopy at projectile energies from 40 to 20 keV. Electron spectra due to autoionization from the states He(2lnl) to He+(1s) for n2, and those from He(3lnl) to He(2s or 2p) for n3, were observed. Line peaks in the spectra were identified by comparing observed electron spectra with those of several theoretical calculations. It was found that doubly excited states of relatively high angular momenta such as the D and F terms were conspicuously created in a quite different manner from the cases of the production of doubly excited states by the use of photon, electron, or ion impacts on neutral He atoms. Rydberg states with large n values were observed with high population in both the He(2lnl) and He(3lnl) series.
Oku, Takayuki; Watanabe, Masao; Sakaguchi, Yoshifumi*; Kawamura, Seiko; Takahashi, Ryuta*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ishikado, Motoyuki*; Ouchi, Keiichi*; Arima, Hiroshi*; et al.
no journal, ,
Sample environment team at the Materials and Life Science Experimental Facility in J-PARC has worked on development and operation of cryogenics, magnets, high temperature, high pressure, soft matter related items and special environment including pulsed magnets, light irradiators and He-3 spin filters. In the talk, our status is presented, and issues are addressed.
Asai, Masato; Ishibashi, Yuichi*; Niwase, Toshitaka*; Makii, Hiroyuki; Ito, Yuta; Sato, Tetsuya; Tsukada, Kazuaki; Sakaguchi, Satoshi*; Morita, Kosuke*; Watanabe, Yutaka*; et al.
no journal, ,
Solar cells for power generation can be used as a high-energy heavy-ion detector because it has diode characteristics. To utilize the solar cells for fission-fragment measurements, we have investigated the response (energy resolution and pulse height defect) of a solar cell to heavy ions of various nuclides with several different energies.
Watanabe, Masao; Oku, Takayuki; Kawamura, Seiko; Takata, Shinichi; Su, Y. H.; Takahashi, Ryuta*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ishikado, Motoyuki*; Sakaguchi, Yoshifumi*; et al.
no journal, ,
At Material Life Science Laboratory (MLF) in J-PARC, each beamline (BL) has standard sample environment (SE) equipment, while our SE team is organized to maintain BL common sample environment equipment and support the users. We have expensive equipment that is not frequently used but indispensable, and that requires specialized knowledge and skills for operation as BL common SE equipment. The SE team has sub-teams as;(1) cryo & magnet, (2) high temperature, (3) stress (high pressure, tension and fatigue machine), (4) soft matter, (5) humidity, (6) special environment (pulsed magnet, light irradiation and computation). In this presentation, we will explain the current status of BL common sample environment equipment.
Oyama, Kenji*; Yokoo, Tetsuya*; Ito, Shinichi*; Suzuki, Junichi*; Iwasa, Kazuaki*; Sato, Taku*; Kira, Hiroshi*; Sakaguchi, Yoshifumi*; Ino, Takashi*; Oku, Takayuki; et al.
no journal, ,