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Pedersen, L. G.*; Sahin, E.*; Grgen, A.*; Bello Garrote, F. L.*; Orlandi, R.; 他61名*
Acta Physica Polonica B; Proceedings Supplement, 16(4), p.4-A14_1 - 4-A14_6, 2023/08
被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)Excited states in Cu were observed for the first time following the
decay of
Ni created by in-flight fission of
U. Based on the coincidences with the observed
-ray transitions, a level scheme comprising eight excited states was constructed, with tentative spin assignments for 5 of them. In addition to the
-decaying states, an isomeric state with a lifetime of 3.8(4) ms was also found to decay by internal conversion.
村松 憲仁*; 土川 雄介; LEPS2 BGOegg Collaboration*; 他61名*
Physical Review C, 107(4), p.L042201_1 - L042201_5, 2023/04
被引用回数:1 パーセンタイル:25.07(Physics, Nuclear)For the first time, differential cross sections and photon beam asymmetries were measured for the reaction by using a linearly polarized photon beam up to 2.4 GeV and a liquid hydrogen target. The
(980) photoproduction signal was clearly observed owing to the absence of contributions from vector-meson photoproduction. The results indicate the
-channel exchange of vector mesons as a mechanism of the
(980) photoproduction at
approximate to 2.1 GeV, putting constraints on the nature of
(980).
Bello Garrote, F. L.*; Sahin, E.*; 角田 佑介*; 大塚 孝治*; Grgen, A.*; Orlandi, R.; 他61名*
Physical Review C, 102(3), p.034314_1 - 034314_13, 2020/09
被引用回数:4 パーセンタイル:36.67(Physics, Nuclear)Detailed spectroscopy of neutron-rich odd- Cu isotopes is of great importance for studying the shell evolution in the region of
Ni. Excited states in
Cu were populated in the
decay of
Ni isotopes, which were produced by the in-flight fission at RIBF, RIKEN. The
Ni isotopes were separated, identified, and implanted in a highly segmented Si detector array for the detection of the
-decay electrons, while the delayed
rays were detected by an array of HPGe cluster detectors. A level scheme of
Cu was built up to
4 MeV, from which the location of the two previously known low-lying isomeric states was clarified. The level structure below 2 MeV was interpreted based on the results of the shell-model calculations and the systematics of odd-
Cu isotopes, revealing the evolution of single-particle states in this region.
冨田 夏希*; 土川 雄介; LEPS2/BGOegg Collaboration*; 他61名*
Physical Review Letters, 124(20), p.202501_1 - 202501_7, 2020/05
被引用回数:12 パーセンタイル:62.27(Physics, Multidisciplinary)We measured missing mass spectrum of the C(
) reaction for the first time in coincidence with potential decay products from
bound nuclei. We tagged an
pair associated with the
process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section was obtained to be 2.2~nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree
production rate. Our results indicate a small branching fraction of the
process and/or a shallow
-nucleus potential.
Li, Y. B.*; 谷田 聖; Belle Collaboration*; 他161名*
Physical Review Letters, 122(8), p.082001_1 - 082001_7, 2019/03
被引用回数:49 パーセンタイル:89.99(Physics, Multidisciplinary)We present the first measurements of absolute branching fractions of decays into
,
, and
final states. The measurements are made using a data set comprising
pairs collected at the
resonance with the Belle detector at the KEKB
collider. We first measure the absolute branching fraction for
using a missing-mass technique, the result is
. We subsequently measure the product branching fractions
,
, and
with improved precision. Dividing these product branching fractions by the result for
yields the following branching fractions:
,
, and
. Our result for
can be combined with
branching fractions measured relative to
to yield other absolute
branching fractions.
Morales, A. I.*; Orlandi, R.; 他61名*
Physics Letters B, 781, p.706 - 712, 2018/06
被引用回数:23 パーセンタイル:83.75(Astronomy & Astrophysics)By studying the decay of the radioactive nuclei
Co and
Co produced at RIBF, RIKEN, the low-lying excited states in
Ni were studied for the first time up to spin 8
. These states originate from the valence neutrons occupying the
orbit, and permit to investigate the seniority quantum number. The data reveal that the seniority isomerism of the 8
state disappears, and this phenomenon is explained by comparison with shell model calculations and the influence of spherical doubly-magic
Ni.
Seidl, R.*; 谷田 聖; Belle Collaboration*; 他161名*
Physical Review D, 96(3), p.032005_1 - 032005_21, 2017/08
被引用回数:17 パーセンタイル:59.70(Astronomy & Astrophysics)The inclusive cross sections for dihadrons of charged pions and kaons () in electron-positron annihilation are reported. They are obtained as a function of the total fractional energy and invariant mass for any di-hadron combination in the same hemisphere as defined by the thrust event-shape variable and its axis. Since same-hemisphere dihadrons can be assumed to originate predominantly from the same initial parton, di-hadron fragmentation functions are probed. These di-hadron fragmentation functions are needed as an unpolarized baseline in order to quantitatively understand related spin-dependent measurements in other processes and to apply them to the extraction of quark transversity distribution functions in the nucleon. The di-hadron cross sections are obtained from a 655 fb
data sample collected at or near the
resonance with the Belle detector at the KEKB asymmetric-energy
collider.
Adare, A.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他361名*
Physical Review C, 95(3), p.034904_1 - 034904_10, 2017/03
被引用回数:21 パーセンタイル:80.34(Physics, Nuclear)The PHENIX Collaboration has measured the ratio of the yields of to
mesons produced in
,
Al,
Au, and
He+Au collisions at
GeV over the forward and backward rapidity intervals
. We find that the ratio in
collisions is consistent with measurements at other collision energies. In collisions with nuclei, we find that in the forward (
-going or
He-going) direction, the relative yield of
mesons to
mesons is consistent with the value measured in
collisions. However, in the backward (nucleus-going) direction, the
meson is preferentially suppressed by a factor of
. This suppression is attributed in some models to the breakup of the weakly bound
meson through final-state interactions with comoving particles, which have a higher density in the nucleus-going direction. These breakup effects may compete with color screening in a deconfined quark-gluon plasma to produce sequential suppression of excited quarkonia states.
白鳥 昴太郎*; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 市川 裕大; 谷田 聖; 他61名*
Physical Review Letters, 109(13), p.132002_1 - 132002_5, 2012/09
被引用回数:33 パーセンタイル:79.05(Physics, Multidisciplinary)J-PARCの中間子ビームを使って、1.92GeVの
反応をこれまでにない1.4MeV(FWHM)という高分解能で測定しペンタクォーク
を探索した。報告されている
の質量領域にはピーク構造は見つからなかった。得られたデータからペンタクォークの生成断面積の上限値として0.26
b/srを得た。