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-ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich 
KrGerst, R.-B.*; Blazhev, A.*; Moschner, K.*; Doornenbal, P.*; Obertelli, A.*; Orlandi, R.; 他62名*
Physical Review C, 105(2), p.024302_1 - 024302_11, 2022/02
被引用回数：6 パーセンタイル：84.97(Physics, Nuclear)The neutron rich krypton isotopes Kr (
=36, 
=58,59,60 respectively) were investigated at the Radioactive Isotope Beam Facility Facility (RIBF) at RIKEN. The nuclei of interest were produced in nuclear reactions induced by radioactive Kr and Rb beams, prduced via in-flight fission of 
U, impinging onto the liquid hydrogen target MINOS. The main reactions occurring were (p,pn), (p,p') and (p,2p). The isotopes of interest were separated in the fragment separator BigRIPS, and their rays detected using the DALI2 -ray spectrometer. The Kr provide insights onto the sudden onset of deformation occurring in Zr and Mo isotopes at =60, which is also associated with shape coexistence. In this experiment the level scheme of these isotopes could be extended, and new yrast and non-yrast states were identified. The results were compared with predictions of the "beyond-mean-field" model and the IBM model, and indications of prolate-oblate shape coexistence at =60 in the Kr isotopes was found.
+Al, +Au, 
+Au, and 
He+Au at 
= 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362名*
Physical Review Letters, 121(22), p.222301_1 - 222301_8, 2018/11
被引用回数：36 パーセンタイル：86.3(Physics, Multidisciplinary)Asymmetric nuclear collisions of +Al, +Au, +Au, and He+Au at = 200 GeV provide an excellent laboratory for understanding particle production, as well as exploring interactions among these particles after their initial creation in the collision. We present measurements of charged hadron production 
in all such collision systems over a broad pseudorapidity range and as a function of collision multiplicity. A simple wounded quark model is remarkably successful at describing the full data set. We also measure the elliptic flow 
over a similarly broad pseudorapidity range. These measurements provide key constraints on models of particle emission and their translation into flow.
collisions at 
= 510 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462名*
Physical Review D, 95(7), p.072002_1 - 072002_19, 2017/04
被引用回数：11 パーセンタイル：49.64(Astronomy & Astrophysics)Dihadron and isolated direct photon-hadron angular correlations are measured in collisions at = 510 GeV. Correlations of charged hadrons of 
GeV/
with 
mesons of 
GeV/ or isolated direct photons of 
GeV/ are used to study nonperturbative effects generated by initial-state partonic transverse momentum and final-state transverse momentum from fragmentation. The nonperturbative behavior is characterized by measuring the out-of-plane transverse momentum component 
perpendicular to the axis of the trigger particle, which is the high-
direct photon or . Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (
). The Gaussian widths and root mean square of are reported as a function of the interaction hard scale to investigate possible transverse-momentum-dependent evolution differences between the -
and direct photon-
correlations and factorization breaking effects. The widths are found to decrease with , which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.
hadrons in nucleus-nucleus collisions at 
from 62.4 GeV to 2.76 TeVAdare, 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623名*
Physical Review C, 93(2), p.024911_1 - 024911_20, 2016/02
被引用回数：17 パーセンタイル：75.53(Physics, Nuclear)Measurements of the fractional momentum loss (
) of high-transverse-momentum-identified hadrons in heavy-ion collisions are presented. Using in Au+Au and Cu+Cu collisions at = 62.4 and 200 GeV measured by the PHENIX experiment at the Relativistic Heavy Ion Collider and and charged hadrons in Pb+Pb collisions measured by the ALICE experiment at the Large Hadron Collider, we studied the scaling properties of 
as a function of a number of variables: the number of participants, 
, the number of quark participants, 
, the charged-particle density, , and the Bjorken energy density times the equilibration time, 
. We find that the , where has its maximum, varies both with centrality and collision energy. Above the maximum, tends to follow a power-law function with all four scaling variables. The data at = 200 and 2.76 TeV, for sufficiently high particle densities, have a common scaling of with and , lending insight into the physics of parton energy loss.
He + Au collisions at = 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623名*
Physical Review Letters, 115(14), p.142301_1 - 142301_9, 2015/09
被引用回数：112 パーセンタイル：96.51(Physics, Multidisciplinary)We present the first measurement of elliptic (
) and triangular (
) flow in high-multiplicity He + Au collisions at = 200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in He + Au and in collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the He + Au system. The collective behavior is quantified in terms of elliptic and triangular anisotropy coefficients measured with respect to their corresponding event planes. The values are comparable to those previously measured in + Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.
