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Yakushev, A.*; Lens, L.*; D
llmann, C. E.*; Block, M.*; 永目 諭一郎*; 佐藤 哲也; 豊嶋 厚史*; 他42名*
Frontiers in Chemistry (Internet), 9, p.753738_1 - 753738_9, 2021/11
被引用回数：10 パーセンタイル：63.67(Chemistry, Multidisciplinary)ニホニウム(Nh, 元素113)とフレロビウム(Fl, 元素114)は、7p軌道が占有されている最初の超重元素である。7p
軌道と7p
軌道の間の大きなスピン軌道分裂に由来する、相対論効果による7p軌道の安定化によって、Flの高い揮発性と化学的不活性が予測された。Nhのもつ7pの不対電子は、より高い化学反応性をもたらすと予想される。気相でのNh化学研究のための最初の実験的試みの結果とともに、Nhの化学反応性の理論的予測について説明する。実験結果から、Flと比較してNh原子の化学反応性が高いことがわかった。非常に反応性の高いFr同位体を用いて、新規に開発した検出器miniCOMPACTのテストを行ったところ、Nhの化学研究が可能であることを確認できた。
Abudin
n, F.*; 谷田 聖; Belle II Collaboration*; 他420名*
Chinese Physics C, 44(2), p.021001_1 - 021001_12, 2020/02
被引用回数：23 パーセンタイル：93.93(Physics, Nuclear)From April to July 2018, a data sample at the peak energy of the 
resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (
) pb
, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II.
0 and resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle ambiguity足立 一郎*; 谷田 聖; Belle Collaboration*; 他421名*
Physical Review Letters, 121(26), p.261801_1 - 261801_11, 2018/12
被引用回数：9 パーセンタイル：57.38(Physics, Multidisciplinary)We present first evidence that the cosine of the 
-violating weak phase 
is positive, and hence exclude trigonometric multifold solutions of the CKM Unitarity Triangle using a time-dependent Dalitz plot analysis of 
with 
decays, where 
denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BaBar and Belle experiments collected at the resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain 
pairs recorded by the BaBar detector and 
pairs recorded by the Belle detector. The results of the measurement are 
and 
. The result for the direct measurement of the angle 
of the CKM Unitarity Triangle is 
. The quoted model uncertainties are due to the composition of the 
decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics 
data sample. CP violation is observed in decays at the level of 
standard deviations. The significance for 
is 
standard deviations. The trigonometric multifold solution 
is excluded at the level of 
standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
for forward 
production in polarized 
collisions at 
GeVAdare, A.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他423名*
Physical Review D, 98(3), p.032007_1 - 032007_14, 2018/08
被引用回数：14 パーセンタイル：59.03(Astronomy & Astrophysics)We have measured the cross section and single spin asymmetries from forward production in longitudinally polarized collisions at GeV using the PHENIX detector at the Relativistic Heavy Ion Collider. The cross sections are consistent with previous measurements at this collision energy, while the most forward and backward longitudinal single spin asymmetries provide new insights into the sea quark helicities in the proton. The charge of the 
bosons provides a natural flavor separation of the participating partons.
-ray spectroscopy of hypernuclei; Recent results and prospect at J-PARC田村 裕和*; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; Hwang, S.; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 17, p.011004_1 - 011004_11, 2017/07
The present status and future prospects of precision -ray spectroscopy of 
hypernuclei are described. A new experiment (J-PARC E13) has been performed at the J-PARC K1.8 line employing a newly-developed germanium (Ge) detector array, Hyperball-J, via the 
reaction on 
He and 
F targets. This is the first study of 
-shell and 
-shell hypernuclei with Ge detectors. The He target spectrum exhibited a -ray peak of 
at 
MeV. Compared with the energy (
MeV) of the corresponding transition for the mirror hypernucleus, 
, the present result clearly indicates a large charge symmetry breaking (CSB) effect. This decisive data for CSB allows a stringent test of baryon-baryon interaction models. As for the F target run, a preliminary spectrum shows several -ray peaks assigned to 
transitions. Future plans of -ray spectroscopy are also discussed.
at forward rapidity in 
collisions at GeVAidala, C.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他425名*
Physical Review D, 95(9), p.092002_1 - 092002_18, 2017/05
被引用回数：7 パーセンタイル：37.12(Astronomy & Astrophysics)We report the first measurement of the fraction of 
mesons coming from 
-meson decay (
) in collisions at GeV. The measurement is performed using the forward silicon vertex detector and central vertex detector at PHENIX, which provide precise tracking and distance-of-closest-approach determinations, enabling the statistical separation of due to -meson decays from prompt . The measured value of is 
for with transverse momenta 
GeV/
and rapidity 
. The measured fraction at PHENIX is compared to values measured by other experiments at higher center of mass energies and to fixed-order-next-to-leading-logarithm and color-evaporation-model predictions. The 
cross section per unit rapidity ![$$[dsigma/dy(pp to bbar{b})]$$](/search/images/ERNWIXDTNFTW0YJPMR2SQ2DQEBOHI1ZAMJOGEYLSPNRH0KK3EQ.gif)
extracted from the obtained and the PHENIX inclusive cross section measured at 200 GeV scaled with color-evaporation-model calculations, at the mean hadron rapidity 
in 510 GeV collisions, is 
b. It is consistent with the fixed-order-next-to-leading-logarithm calculations.
= 200 GeVAdare, A.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他426名*
Physical Review C, 93(3), p.034904_1 - 034904_29, 2016/03
被引用回数：43 パーセンタイル：93.7(Physics, Nuclear)The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy flavor production in minimum bias Au + Au collisions at = 200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons. Previous heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transverse momentum are measured in Au + Au collisions. We compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in 
collisions at = 200 GeV and find the fractions to be similar within the large uncertainties on both measurements for 
4 GeV/. We use the bottom electron fractions in Au + Au and along with the previously measured heavy flavor electron 
to calculate the for electrons from charm and bottom hadron decays separately. We find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3
4 GeV/.
Han, Y.*; 長谷川 勝一; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; J-PARC E42 Collaboration*; 他23名*
JPS Conference Proceedings (Internet), 8, p.021002_1 - 021002_5, 2015/09
The famed yet elusive H-dibaryon, an exotic quark state (
), was predicted several decades ago and also supported by recent Lattice QCD calculations. The E42 experiment has been approved at J-PARC to search for the H-dibaryon with high statistics. A large acceptance hyperon spectrometer with a time projection chamber (TPC) will be used for searching the H-dibaryon from 
reaction off nuclei via its possible following decays such as 
. The E42 experiment has high sensitivity both above and below threshold and will be the definitive experiment on the existence of the H-dibaryon, once and for all. Recent progress and achievements of the E42 collaboration will be presented, which include simulations on estimation of TPC performance in the electric field and the magnetic field, testing and optimization of a prototype TPC, and preparation of various detectors.
= 62.4 and 200 GeVAdare, A.*; 今井 憲一; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他420名*
Physical Review C, 92(3), p.034913_1 - 034913_20, 2015/09
被引用回数：20 パーセンタイル：78.02(Physics, Nuclear)We have studied the dependence of azimuthal anisotropy 
for inclusive and identified charged hadrons in Au + Au and Cu + Cu collisions on collision energy, species, and centrality. The values of as a function of transverse momentum 
and centrality in Au+Au collisions at = 200 and 62.4 GeV are the same within uncertainties. However, in Cu + Cu collisions we observe a decrease in values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au + Au and Cu + Cu collisions we find that depends both on eccentricity and the number of participants, 
. We observe that divided by eccentricity (
) monotonically increases with and scales as 
. The Cu + Cu data at 62.4 GeV falls below the other scaled data. For identified hadrons, divided by the number of constituent quarks 
is independent of hadron species as a function of transverse kinetic energy 
between 
GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu + Cu data at 62.4 GeV, of 
vs 
for all measured particles.
GeVAdare, A.*; 今井 憲一; 谷田 聖; PHENIX Collaboration*; 他421名*
Physical Review Letters, 114(19), p.192301_1 - 192301_8, 2015/05
被引用回数：133 パーセンタイル：97.3(Physics, Multidisciplinary)We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central 
+ Au and minimum bias collisions at GeV. The charged hadron is measured at midrapidity 
, and the energy is measured at large rapidity (
, Au-going direction). An enhanced near-side angular correlation across 
is observed in +Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength for inclusive charged hadrons at midrapidity up to 
. We also present the measurement of for identified 
and and (anti)protons in central + Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from + Pb at = 5.02 TeV. The magnitude of the mass ordering in +Au is found to be smaller than that in +Pb collisions, which may indicate smaller radial flow in lower energy +Au collisions.
