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Se(n,
) cross section up to 200 keV at the n_TOF facility at CERNSosnin, N. V.*; 原田 秀郎; 木村 敦; 他128名*
Physical Review C, 107(6), p.065805_1 - 065805_9, 2023/06
被引用回数：1 パーセンタイル：0.00(Physics, Nuclear)The Se(n,) reaction is of importance for Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT = 5 keV and kT = 100 keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in Se abundances produced through the slow neutron capture process in selected stellar models, compared to using previous recommendation of the cross section.
Ge(n,) cross section below 70 keV measured at n_TOF CERNLederer-Woods, C.*; 原田 秀郎; 木村 敦; 他128名*
European Physical Journal A, 58(12), p.239_1 - 239_9, 2022/12
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)Neutron capture reaction cross sections on Ge are of importance to determine Ge production during the astrophysical slow neutron capture process. We present new resonance data on Ge(n,) reactions below 70 keV neutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment.
Hg and asymmetric fission of neutron-deficient pre-actinidesJhingan, A.*; Andreyev, A. N.; 他28名*
Physical Review C, 106(4), p.044607_1 - 044607_9, 2022/10
被引用回数：8 パーセンタイル：72.81(Physics, Nuclear)Fission of Hg was induced by fusion of 
Xe and 
Fe. The two fragments were detected in coincidence using VAMOS++ supplemented with a new SEcond Detection arm. For the first time in the pre-actinide region, access to the pre-neutron mass and total kinetic energy distributions, and the simultaneous isotopic identification of one the fission fragment, was achieved. The present work describes the experimental approach, and discusses the pre-neutron observables in the context of an extended asymmetric fission island located southwest of 
Pb. A comparison with different models is performed, demonstrating the importance of this new asymmetric-fission island for elaborating on driving effects in fission.
pairs from open heavy flavor and Drell-Yan in 
collisions at 
GeVAidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他287名*
Physical Review D, 99(7), p.072003_1 - 072003_41, 2019/04
被引用回数：19 パーセンタイル：66.48(Astronomy & Astrophysics)PHENIX reports differential cross sections of pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in 
collisions at GeV at forward and backward rapidity (
). The pairs from 
, 
, and Drell-Yan are separated using a simultaneous fit to unlike- and like-sign muon pair spectra in mass and 
. The azimuthal opening angle correlation between the muons from and decays and the pair- distributions are compared to distributions generated using 
and 
models, which both include next-to-leading order processes. The measured distributions for pairs from are consistent with calculations. The data presents narrower azimuthal correlations and softer distributions compared to distributions generated from . The data are well described by both models. The extrapolated total cross section for bottom production is 
[
b], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy, and is approximately a factor of two higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.
-ray spectroscopy of 
Te at relativistic energiesVaquero, V.*; Jungclaus, A.*; Doornenbal, P.*; Wimmer, K.*; Moro, A. M.*; Orlandi, R.; 他28名*
Physical Review C, 99(3), p.034306_1 - 034306_14, 2019/03
被引用回数：16 パーセンタイル：79.37(Physics, Nuclear)The reduced transition probability B(E2; 0
) to the first excited 2
state of the neutron-rich nucleus Te, with two protons and two neutrons outside the doubly magic 
Sn core, was measured via Coulomb excitation at relativistic energies at the RIKEN Radioactive Isotope Beam Factory. In the experiment, Te isotopes impinged on a 950 mg/cm
Au target. The measured B(E2) value, 0.191(26) eb, is in good agreement with the result of a recent experiment employing low-energy Coulomb excitation. Because of the high statistics gathered in this work the error of the deduced B(E2) value is dominated by the systematic uncertainties involved in the analysis of Coulomb excitation experiments at beam energies around 150 MeV/u. These uncertainties were assessed for the first time and will be of use for future experiments at RIBF.
Ge(n,) cross sections and implications for stellar nucleosynthesisLederer-Woods, C.*; Battino, U.*; Ferreira, P.*; Gawlik, A.*; 木村 敦; n_TOF Collaboration*; 他128名*
Physics Letters B, 790, p.458 - 465, 2019/03
被引用回数：14 パーセンタイル：75.77(Astronomy & Astrophysics)
cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at 
=30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of Ge produced in stars, which would explain the low isotopic abundance of Ge in the solar system.
collisions at GeVAidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他287名*
Physical Review D, 98(7), p.072004_1 - 072004_13, 2018/10
被引用回数：2 パーセンタイル：11.43(Astronomy & Astrophysics)Dihadron and isolated direct photon-hadron angular correlations are measured in collisions at GeV. The correlations are sensitive to nonperturbative initial-state and final-state transverse momentum 
and 
in the azimuthal nearly back-to-back region 
. In this region, transverse-momentum-dependent evolution can be studied when several different hard scales are measured. To have sensitivity to small transverse momentum scales, nonperturbative momentum widths of 
, the out-of-plane transverse momentum component perpendicular to the trigger particle, are measured. These widths are used to investigate possible effects from transverse-momentum-dependent factorization breaking. When accounting for the longitudinal momentum fraction of the away-side hadron with respect to the near-side trigger particle, the widths are found to increase with the hard scale; this is qualitatively similar to the observed behavior in Drell-Yan and semi-inclusive deep-inelastic scattering interactions. The momentum widths are also studied as a function of center-of-mass energy by comparing to previous measurements at 
GeV. The nonperturbative jet widths also appear to increase with 
at a similar 
, which is qualitatively consistent to similar measurements in Drell-Yan interactions.
production in , Al, and Au collisions with transversely polarized proton beams at 
GeVAidala, C.*; 長谷川 勝一; 今井 憲一; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他286名*
Physical Review D, 98(1), p.012006_1 - 012006_11, 2018/07
被引用回数：13 パーセンタイル：51.76(Astronomy & Astrophysics)We report the transverse single-spin asymmetries of production at forward and backward rapidity, 
, as a function of transverse momentum () and Feynman-
(
). The data analyzed were recorded by the PHENIX experiment at the Relativistic Heavy Ion Collider in 2015 from , Al, and Au collisions with transversely polarized proton beams at GeV. At this collision energy, single-spin asymmetries for heavy-flavor particle production of collisions provide access to the spin-dependent gluon distribution and higher-twist correlation functions inside the nucleon, such as the gluon Qiu-Sterman and trigluon correlation functions. Proton + nucleus collisions offer an excellent opportunity to study nuclear effects on the correlation functions. The data indicate negative asymmetries at the two-standard-deviation level in the Au data for 
GeV/
at both forward and backward rapidity, while in and Al collisions the asymmetries are consistent with zero within the range of experimental uncertainties.
production in longitudinally polarized collisions at GeVAdare, A.*; 今井 憲一; 長谷川 勝一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他328名*
Physical Review D, 94(11), p.112008_1 - 112008_10, 2016/12
被引用回数：10 パーセンタイル：42.68(Astronomy & Astrophysics)We report the double-helicity asymmetry, 
, in inclusive production at forward rapidity as a function of transverse momentum and rapidity 
. The data analyzed were taken during GeV longitudinally polarized collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, particles are predominantly produced through gluon-gluon scatterings, thus is sensitive to the gluon polarization inside the proton. We measured by detecting the decay daughter muon pairs 
within the PHENIX muon spectrometers in the rapidity range . In this kinematic range, we measured the to be 
. The can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken : one at moderate range 
where recent data of jet and 
double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-x region 
Thus our new results could be used to further constrain the gluon polarization for 
.
中島 宏; Mokhov, N.*; 他28名*
Progress in Nuclear Science and Technology (Internet), 4, p.191 - 196, 2014/04
ミュオン及び中性子反応に関する日米協力研究JASMINでは、一連の実験的研究を、米国国立フェルミ加速器研究所における120GeV陽子ビームを用いて行った。このビームにより生じた二次粒子を、ターゲット周囲において、さまざまな検出器、ドジメーターを用いて測定した。また、鉄,コンクリート,岩石等を透過する二次粒子についても同様に測定した。また、これら核破砕反応に関する放射化断面積及び残留核の質量分布等の核データについては放射化法により測定した。二重微分中性子生成量についても、飛行時間法を用いて測定した。これらについてPHITSやMARS等の計算結果と比較したところ、全体的に一致することが示された。現在、さらに詳細な解析を進めている。
Poulaki, E. M.*; 安邊 啓明; 他28名*
no journal, ,
We analyze samples from IODP Expedition 402, which occurred from Feb-April 2024 and drilled the continent-ocean transition in the Tyrrhenian Sea offshore Italy. Two drill sites comprise a sequence of (1) variably deformed granitic gneisses intercalated with ~cm-scale slivers of peridotites and basalts, and (2) a heterogeneous section of primarily serpentinized peridotites and cm-thick granitoids emplaced between the ultramafics. All peridotites are serpentinized with moderate to high alteration. The presence of both peridotites and granitoids showcases a diverse lithological and rheological heterogeneity that has not been previously observed in in-situ mantle sections. Initial observations suggest strain localization in a ~5 m-thick zone. Preliminary zircon U-Pb ages and apatite U-Pb ages constraints coupled with the microstructures require rapid exhumation after the granitoids' emplacement. Collectively, the presence of granitic gneisses within the detachment fault, as well as the young age of felsic intrusions, suggests that the weak granitoids may have accommodated the exhumation of this mantle section to the surface.
