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Walter, H.*; Colonna, M.*; Cozma, D.*; Danielewicz, P.*; Ko, C. M.*; Kumar, R.*; 小野 章*; Tsang, M. Y. B*; Xu, J.*; Zhang, Y.-X.*; et al.
Progress in Particle and Nuclear Physics, 125, p.103962_1 - 103962_90, 2022/07
被引用回数：88 パーセンタイル：95.20(Physics, Nuclear)原子核-原子核衝突や原子核の状態方程式の研究において、反応計算モデルは重要なツールとなり、世界中で開発が進んでいる。本論文は、原子力機構のJQMD-2.0を含め、現在開発中の複数のコード開発者の協力により、これらコードを同じ条件で比較することで共通点や差異を明らかにしたプロジェクトTransport Model Evaluation Project (TMEP)を総括したものである。参加したコードはBoltzmann-Uehling-Uhlenbeck(BUU)法に基づく13のコードと、Quantum Molecular Dynamics (QMD)法に基づく12のコードであった。プロジェクトでは、Au原子核同士を衝突させてその終状態を観測する現実的な計算や、一辺が640nmの箱に核子を詰めて時間発展させる仮想的な計算を行った。その結果、BUU法コードとQMD法コードは計算原理が異なるため、計算の設定に関係なく系統的な差異が生じることが明らかになった。その一方で、同じ方法を採用するコード間の比較では、時間発展を細かく計算することでコード間の差は埋まっていき、一定の収束値を持つことが示された。この結果は今後開発される同分野のコードのベンチマークデータとして有用なものであるだけでなく、原子核基礎物理学の実験や理論研究の標準的な指針としても役に立つことが期待される。
nuclear modification at backward and forward rapidity in 
, Al, and Au collisions at 
GeVAcharya, U. A.*; 長谷川 勝一; 今井 憲一*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他310名*
Physical Review C, 105(6), p.064912_1 - 064912_15, 2022/06
被引用回数：15 パーセンタイル：91.22(Physics, Nuclear)Suppression of the 
nuclear-modification factor has been seen as a trademark signature of final-state effects in large collision systems for decades. In small systems, the nuclear modification was attributed to cold-nuclear-matter effects until the observation of strong differential suppression of the state in 
collisions suggested the presence of final-state effects. Results of and measurements in the dimuon decay channel are presented here for , Al, and Au collision systems at GeV. The results are predominantly shown in the form of the nuclear-modification factor, 
, the ratio of the invariant yield per nucleon-nucleon collision in collisions of proton on target nucleus to that in collisions. Measurements of the and nuclear-modification factor are compared with shadowing and transport-model predictions, as well as to complementary measurements at Large-Hadron-Collider energies.
毛受 弘彰*; 谷田 聖; 他31名*
Proceedings of Science (Internet), 395, p.301_1 - 301_9, 2022/03
Precise understanding of hadronic interactions at high energies is a key to improve mass composition measurements of very high energy cosmic-rays and to solve the muon excess issue observed in high energy cosmic-ray experiments using an air-shower technique. The LHCf and RHICf experiments measures the differential production cross sections of very forward neutral particle as photons, neutral pions and neutrons at LHC and RHIC, respectively. These data are critically important to test and tune hadronic interaction models used for air-shower simulations. In this presentation, we introduce the recent results of both the experiments as well as our future operation plans. LHCf published an updated result of forward neutron measurement at 
, 
TeV. From the observed neutron energy spectra, we also obtained the average inelasticity, which is one of the key parameters for air shower development, as 
. In addition, several analysis are on-going; neutral pion measurement at , TeV, central-forward correlation analysis with LHCf+ATLAS, photon measurement by RHICf. LHCf plans to have operations at and O during the LHC-Run3 period. At collisions, new silicon readout system will be introduced to improve the read-out speed, and 10 times more statistics of the previous operation in 2015 will be obtained. Thanks to high statistics, rare particles such as 
, 
and 
will be addressed also. We also plan another operation at RHIC in 2024 with a new detector. The detector, a calorimeter composed of tungsten, Si pad and pixel layers, will have a much wider acceptance and higher sensitivity of measurement than the current detector.
using 
decaysAbudin
n, F.*; 谷田 聖; Belle II Collaboration*; 他319名*
Journal of High Energy Physics (Internet), 2022(2), p.63_1 - 63_33, 2022/02
被引用回数：4 パーセンタイル：37.56(Physics, Particles & Fields)We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle (also known as~
) using a model-independent Dalitz plot analysis of 
, where 
is either a 
or 
meson and 
is either a 
or 
. This is the first measurement that simultaneously uses Belle and Belle~II data, combining samples corresponding to integrated luminosities of 711 fb
and 128 fb, respectively. All data were accumulated from energy-asymmetric 
collisions at a centre-of-mass energy corresponding to the mass of the 
resonance. We measure 
, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the -decay strong-phase parameters.
pairs in annihilationLi, H.*; 谷田 聖; Belle Collaboration*; 他131名*
Physical Review D, 100(9), p.092008_1 - 092008_26, 2019/11
被引用回数：13 パーセンタイル：54.51(Astronomy & Astrophysics)This work reports the first observation of azimuthal asymmetries around the thrust axis in annihilation of pairs of back-to-back charged pions in one hemisphere, and 
and mesons in the opposite hemisphere. These results are complemented by a new analysis of pairs of back-to-back charged pions. The and asymmetries rise with the relative momentum 
of the detected hadrons as well as with the transverse momentum with respect to the thrust axis. These asymmetries are sensitive to the Collins fragmentation function 
and provide complementary information to previous measurements with charged pions and kaons in the final state. In particular, the final states will provide additional information on the flavor structure of . This is the first measurement of the explicit transverse-momentum dependence of the Collins fragmentation function from Belle data. It uses a dataset of 980.4 fb collected by the Belle experiment at or near a center-of-mass energy of 10.58 GeV.
states in 
Ni probed via two-neutron transferFlavigny, F.*; Elseviers, J.*; Andreyev, A. N.; Bauer, C.*; Bildstein, V.*; Blazhev, A.*; 他31名*
Physical Review C, 99(5), p.054332_1 - 054332_6, 2019/05
被引用回数：11 パーセンタイル：68.34(Physics, Nuclear)The Ni isotope is known for exhibiting signs of shape coexistence at very low excitation energies. In this work, carried out at REX-Isolde, CERN, the 
Ni(
,) reaction in inverse kinematics was studied for the first time and used to assess directly the active neutrons orbitals responsible its shape coexistence. The main states populated were the 
ground state, the second state at 1604~keV, and the first excited 2 state at 2033 keV. The analysis of the differential transfer cross-sections and comparison with theoretical DWBA calculations permitted to quantify the contribution of neutron orbits below the 
=40 gap in the structure of these states. This information is essential to better understand the phenomenon of shape coexistence in the region of medium-heavy nuclei.
Aidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他312名*
Nature Physics, 15(3), p.214 - 220, 2019/03
被引用回数：112 パーセンタイル：97.37(Physics, Multidisciplinary)Experimental studies of the collisions of heavy nuclei at relativistic energies have established the properties of the quark-gluon plasma (QGP), a state of hot, dense nuclear matter in which quarks and gluons are not bound into hadrons. In this state, matter behaves as a nearly inviscid fluid that efficiently translates initial spatial anisotropies into correlated momentum anisotropies among the particles produced, creating a common velocity field pattern known as collective flow. In recent years, comparable momentum anisotropies have been measured in small-system proton-proton and proton-nucleus (p+A) collisions, despite expectations that the volume and lifetime of the medium produced would be too small to form a QGP. Here we report on the observation of elliptic and triangular flow patterns of charged particles produced in proton-gold (p+Au), deuteron-gold (d+Au) and helium-gold (
He+Au) collisions at a nucleon-nucleon centre-of-mass energy 
= 200 GeV. The unique combination of three distinct initial geometries and two flow patterns provides unprecedented model discrimination. Hydrodynamical models, which include the formation of a short-lived QGP droplet, provide the best simultaneous description of these measurements.
= 200 GeVAdare, A.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他317名*
Physical Review C, 99(2), p.024903_1 - 024903_16, 2019/02
被引用回数：13 パーセンタイル：73.82(Physics, Nuclear)We present measurements of elliptic and triangular azimuthal anisotropy of charged particles detected at forward rapidity 
in AuAu collisions at GeV, as a function of centrality. The multiparticle cumulant technique is used to obtain the elliptic flow coefficients 
, 
, 
, and 
, and triangular flow coefficients 
and 
. Using the small-variance limit, we estimate the mean and variance of the event-by-event 
distribution from and . In a complementary analysis, we also use a folding procedure to study the distributions of and 
directly, extracting both the mean and variance. Implications for initial geometrical fluctuations and their translation into the final state momentum distributions are discussed.
+Au Collisions at 200, 62.4, 39, and 19.6 GeV and +Au Collisions at 200 GeV and implications for collective behaviorAidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他311名*
Physical Review Letters, 120(6), p.062302_1 - 062302_8, 2018/02
被引用回数：55 パーセンタイル：90.63(Physics, Multidisciplinary)Recently, multiparticle-correlation measurements of relativistic 
HeAu, Pb, and even collisions have shown surprising collective signatures. Here we present beam-energy-scan measurements of 2-, 4-, and 6-particle angular correlations in Au collisions at =200, 62.4, 39, and 19.6 GeV. We also present measurements of 2- and 4-particle angular correlations in Au collisions at =200 GeV. We find the 4-particle cumulant to be real-valued for Au collisions at all four energies. We also find that the 4-particle cumulant in Au has the opposite sign as that in Au, indicating that the correlations are geometrical and therefore collective in origin. Further we find that the 6-particle cumulant agrees with the 4-particle cumulant in Au collisions at 200 GeV, which indicates that nonflow effects are subdominant and provides strong evidence of collectivity.
collisions at 
=200 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431名*
Physical Review D, 95(11), p.112001_1 - 112001_15, 2017/06
被引用回数：17 パーセンタイル：59.93(Astronomy & Astrophysics)The cross section and transverse single-spin asymmetries of 
and 
from open heavy-flavor decays in polarized collisions at = 200 GeV were measured by the PHENIX experiment during 2012 at the Relativistic Heavy Ion Collider. Because heavy-flavor production is dominated by gluon-gluon interactions at = 200 GeV, these measurements offer a unique opportunity to obtain information on the trigluon correlation functions. The measurements are performed at forward and backward rapidity (
) over the transverse momentum range of 
GeV/
for the cross section and 
GeV/ for the asymmetry measurements. The obtained cross section is compared to a fixed-order-plus-next-to-leading-log perturbative-quantum-chromodynamics calculation. The asymmetry results are consistent with zero within uncertainties, and a model calculation based on twist-3 three-gluon correlations agrees with the data.
bound states in the 
C
reaction at 1.8 GeV/ in J-PARC永江 知文*; 江川 弘行; 長谷川 勝一; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
Proceedings of Science (Internet), 281, p.038_1 - 038_7, 2017/05
We have carried out a pilot data taking of the J-PARC E05 experiment to search for the bound state peaks of 
Be in the C reaction at 1.8 GeV/. The measurement was performed at the K1.8 beam line of the J-PARC hadron experimental hall with a typical 
beam intensity of 
every six seconds. So far the best energy resolution of about 6 MeV FWHM was achieved with the existing SKS spectrometer. With a reasonable statistics, we have succeeded to observe peak structures in the bound region, which seems to suggest that the potential depth of would be deeper than 14 MeV estimated in the previous measurements.
-nucleus interaction by using the C(K
, p) reaction at J-PARC市川 裕大; 江川 弘行; 長谷川 勝一; 早川 修平; 細見 健二; 今井 憲一; 金原 慎二; 中田 祥之; 佐甲 博之; 佐藤 進; et al.
JPS Conference Proceedings (Internet), 13, p.020007_1 - 020007_5, 2017/02
被引用回数：0 パーセンタイル：0.00(Physics, Particles & Fields)これまで反K中間子と原子核の間の相互作用はK中間子原子(K-中間子と原子核の電磁相互作用による束縛状態)のX線を用いて研究が行われてきた。しかし、このK中間子原子のX線測定では理論モデルの種類によって結果が大きく依存するという問題がため、X線測定だけでは相互作用を決定することが困難である。そこで、われわれはC(K, p)反応におけるエネルギースペクトルを測定し、理論計算と比較する手法を用いて反K中間子と原子核の間の相互作用を決定しようとしている。この手法は既にKEK E548実験で行われているが、実験セットアップ上の問題点が指摘されているため、過去の高エネルギー加速器研究機構での実験では不十分である。そこで、われわれはJ-PARCにおいて再実験を行い、正しくC(K, p)のスペクトルを取得することに成功した。
search in hadronic reaction at J-PARC高橋 智則*; 江川 弘行; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 佐甲 博之; 佐藤 進; 杉村 仁志; 谷田 聖; et al.
JPS Conference Proceedings (Internet), 8, p.022011_1 - 022011_6, 2015/09
A search for the pentaquark in the 
reaction was performed at the J-PARC Hadron Facility. Two data samples were collected in 2010 and 2012 at 
beam momenta of 1.92 and 2.0 GeV/, respectively. No peak structure was observed in the missing mass spectra obtained from either data set. The upper limit for the production cross section averaged over the scattering-angle range of 
to 
in the laboratory frame was found to be 0.28 
b/sr. The decay width of the can be directly connected to the production cross section through a theoretical calculation using an effective Lagrangian. The estimated upper limits of the width were 0.41 and 2.8 MeV for the spin-parities of 
and 
, respectively.
threshold via the 
reaction on deuteron山我 拓巳*; 谷田 聖; J-PARC E31 Collaboration*; 他70名*
JPS Conference Proceedings (Internet), 8, p.021016_1 - 021016_5, 2015/09
We are planning to carry out an experimental study of hyperon resonance via the 
reaction using kaon beam which has momentum of 1 GeV/ at the J-PARC hadron experimental facility. In the presented reaction, 
can be produced dynamically from meson-baryon resonant state. The performance of the counters was tested at the previous beam time of the J-PARC. The counters worked as expected. The preparation of experimental setup had been done.
Poulaki, E. M.*; 安邊 啓明; 他31名*
no journal, ,
デタッチメント断層に沿ったひずみの局在化と上昇速度の制御機構、およびマントル上昇中の蛇紋岩化と火成活動の役割は、まだ十分に解明されていない。IODP第402次航海では、ティレニア海の大陸-海洋遷移部を掘削し、この背弧海盆における新生代後期の伸長過程で上昇・定置したマントル物質を回収した。試料の分析の結果、岩相の不均質性と既存構造の存在が断層のすべり挙動に大きな影響を与えることが示された。また、岩石の年代測定を行い、せん断帯の進化過程を制約することができた。
