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and its impact on photoproduction of light hyperonsKhemchandani, K. P.*; Mart
nez Torres, A.*; Kim, S.-H.*; Nam, S.-I.*; Hosaka, Atsushi
Acta Physica Polonica A, 142(3), p.329 - 336, 2022/09
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Hirade, Tetsuya; Michishio, Koji*; Kobayashi, Yoshinori*; Oshima, Nagayasu*
Acta Physica Polonica A, 137(2), p.109 - 112, 2020/02
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Recently, it was reported that the positronium (Ps) bubble in Room Temperature Ionic Liquids (RTILs) showed some phenomena that were very different from them observed in other molecular liquids. Now the reason of these interesting phenomena is being understood. The structure caused by the ionic interaction between anions and cations can exist even at the higher temperatures than the melting temperatures. It was the reason why the oscillation of Ps bubble was observed at the temperatures near the melting temperatures in RTILs. The temperature dependence of the Ps bubble size estimated by the triplet Ps (
-Ps) pick-off annihilation lifetime indicated that there was a nano-meter structure remained by ionic interactions even at high temperatures. The -Ps pick-off annihilation lifetime will be a strong tool to study nano-structure in RTILs.
scattering parameters and possible 
bound state from 
photoproduction on the deuteronIshikawa, Takatsugu*; Tsuchikawa, Yusuke; FOREST Collaboration*; 48 of others*
Acta Physica Polonica B, 51(1), p.27 - 32, 2020/00
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Hirade, Tetsuya
Acta Physica Polonica A, 132(5), p.1470 - 1472, 2017/11
Times Cited Count：3 Percentile：29.1(Physics, Multidisciplinary)The positron annihilation lifetime measurements in RTILs showed very strange results. Finally, positron annihilation age-momentum correlation (AMOC) measurements indicated that it was caused by slow bubble formation in RTILs. Then I discovered the oscillation of o-Ps annihilation rates in room temperature ionic liquids (RTILs) which indicated, probably, the oscillation of the Ps bubble. Stepanov et al. calculated change of the bubble size in many liquids and the oscillation of the bubble was not expected except for a liquid He. It means that the structure of RTILs in nanometer scale is very different from usual liquids. Moreover, o-Ps pick-off annihilation rates seems to be too small for the macroscopic surface tension of RTILs. I am going to discuss what you can study by the positron annihilation methods for the structure of RTILs in nanometer scale.
invariant-mass spectrum in the 
reaction?Sekihara, Takayasu; Oset, E.*; Ramos, A.*
Acta Physica Polonica B, 48(10), p.1869 - 1874, 2017/10
Times Cited Count：1 Percentile：12.03(Physics, Multidisciplinary)
Su(2) GroupMinato, Futoshi
Acta Physica Polonica B; Proceedings Supplement, 10(1), p.131 - 138, 2017/00
Times Cited Count：0 Percentile：0.08(Physics, Nuclear)The random phase approximation (RPA) is one of the useful approaches to describe a collective motion of nuclei. However, RPA intrinsically considers only 1 particle-1 hole (1p1h) excitations, as a result it fails to describe the width of the excited states, for example the Gamow-Teller (GT) state. To include higher-order particle-hole excitations, one can extend RPA to Second RPA (SRPA) which includes 2p2h excitations in a similar way to RPA with the quasi-boson-approximation (QBA). However, it fails to describe the GT distribution even with those model. A part of the problem may arise from the use of QBA. In past studies, SRPA was compared with exact solution using the Lipkin Model and the validity of application of QBA to them was examined. In this work, we examine proton-neutron SRPA (pnSRPA) in SU(4) basis. SU(4) is naturally required in this case to take into account two different particles having two levels each. The first and second excited states are calculated by the diagonalization of Hamiltonian and pnSRPA.
Oset, E.*; 10 of others*; Oka, Makoto
Acta Physica Polonica B, 47(2), p.357 - 365, 2016/02
Times Cited Count：3 Percentile：27.79(Physics, Multidisciplinary)We review results from studies with unconventional many-hadron systems containing mesons: systems with two mesons and one baryon, three mesons, some novel systems with two baryons and one meson, and finally, systems with many vector mesons, up to six, with their spins aligned forming states of increasing spin. We show that in many cases, one has experimental counterparts for the states found, while in some other cases, they remain as predictions, which we suggest to be searched in BESIII, Belle, LHCb, FAIR and other facilities.
Zmeskal, J.*; Tanida, Kiyoshi; 75 of others*
Acta Physica Polonica B, 46(1), p.101 - 112, 2015/01
Times Cited Count：10 Percentile：58.48(Physics, Multidisciplinary)Rudolph, D.*; Forsberg, U.*; Golubev, P.*; Sarmiento, L. G.*; Yakushev, A.*; Andersson, L.-L.*; Di Nitto, A.*; D
llmann, Ch. E.*; Gates, J. M.*; Gregorich, K. E.*; et al.
Acta Physica Polonica B, 45(2), p.263 - 272, 2014/02
Times Cited Count：22 Percentile：75.33(Physics, Multidisciplinary)Produced in the reaction of 
Ca beam with an 
Am target, thirty correlated 
-decay chains were observed. Observed decay chains are consistent with a previously reported decay chain, which confirms the identification of the element 115. In addition, an -photon coincidence measurement was performed, and 
rays as well as X-ray candidates were observed in this decay chain. The -ray observation in the heaviest region of superheavy nuclei brings a big progress in the superheavy nuclear structure studies.
Forsberg, U.*; Golubev, P.*; Sarmiento, L. G.*; Jeppsson, J.*; Rudolph, D.*; Andersson, L.-L.*; Ackermann, D.*; Asai, Masato; Block, M.*; Eberhardt, K.*; et al.
Acta Physica Polonica B, 43(2), p.305 - 311, 2012/02
The atomic numbers and mass numbers of superheavy elements produced in the reactions of Ca beam with actinide targets have not been identified with direct experimental evidences. This causes a little doubt about a new element synthesis. The aim of this study is to identify the atomic numbers of those superheavy elements through characteristic X-ray measurements. To produce and separate superheavy elements, we employed a gas-filled separator TASCA at GSI, and constructed high-efficiency --electron multi-coincidence detector setup at the focal plane of TASCA. Transmission efficiencies and focusing abilities were tested experimentally, and compared with simulations. We achieved a good performance to realize X-ray measurement for the element 115.
Zieli
ska, M.*; Czosnyka, T.*; Wrzosek-Lipska, K.*; Choiski, J.*; Hatsukawa, Yuichi; Iwanicki, J.*; Koizumi, Mitsuo; Kusakari, Hideshige*; Matsuda, Makoto; Morikawa, Tsuneyasu*; et al.
Acta Physica Polonica B, 36(4), p.1289 - 1292, 2005/04
The nuclei 
Mo and 
Mo have been Coulomb excited using various combinations of beams and targets. The investigation of the eletromagnetic structure of these isotopes provides an experimental background for a theoretical description of the shape coexistence observed in the previously studied 
Mo isotope.
Hirade, Tetsuya
Acta Physica Polonica A, 107(4), p.615 - 622, 2005/00
Positronium (Ps) formation by weakly localized long-lived electrons (trapped electrons or anions) and positrons at low temperatures successfully explained the Ps formation enhancement at low temperatures observed in polymers and molecular solids. This Ps formation is completely different from Ps formations by Ore process or spur process. The phenomena expected by this Ps formation mechanism, such as an effect due to visible light exposure, the density effect of weakly localized electrons and the delayed Ps formation were successfully observed as the experimental evidence of this Ps formation process. Some possibilities for application of this new Ps formation were also given. One is a new idea for estimation of spin polarity positrons. Another is the possibility of application to study the local molecular motion by observing the decay of Ps formation possibility by this Ps formation process.
Stepanov, S. V.*; Byakov, V. M.*; He, C.*; Hirade, Tetsuya; Mikhin, K. V.*
Acta Physica Polonica A, 107(4), p.642 - 650, 2005/00
Role of trapped and solvated electrons in Ps formation is discussed. Combination of thermalized positron with such electrons is energetically possible and may contribute to Ps formation. Contrary to the positron reaction with a quasi-free electron, this process is not limited to picosecond times, but proceeds on a timescale of nanoseconds. In this case conventional exponential deconvolution of row lifetime positron annihilation spectra becomes questionable. Rigorous treatment of the data needs nonexponential deconvolution, based on an adequate physical input. Such an approach is suggested here. Its reduced form is used for interpretation of the Ps formation data in polyethylene, EMMA and PMMA in dark and in light vs. time of the measurement and temperature. Parameters characterized accumulation of trapped electrons and their recombination with counter ions and positrons are obtained.
Debski, W.; Ando, Masataka
Acta Geophysica Polonica, 52(1), p.1 - 14, 2004/00
None
Kato, Harukazu; Sakai, Hironori; Kambe, Shinsaku; Walstedt, R. E.; Tokiwa, Yoshifumi; Onuki, Yoshichika
Acta Physica Polonica B, 34(2), p.1063 - 1066, 2003/09
We performed 
Ga-NMR/NQR studies for UPtGa, which is a 5
-itinerant antiferromagnets with Neel temperature 
= 26 K and an electronic specific coefficient = 57 mJ/mol K
. From the NMR spectrum in the paramagnetic temperature region, the hyperfine coupling constants 
in the paramagnetic state have been evaluated. The magnitude of the transferred field has been evaluated from the zero-applied-field spectrum, yielding a value for the hyperfine coupling constant 
in the antiferromagnetic state. The estimated value of is an order of magnitude larger than that of . This implies the existence of a long-ranged hyperfine interaction path. The mechanism of the hyperfine interaction will be discussed in terms of RKKY interactions.
antiferromagnet UPt
SiMetoki, Naoto; Koike, Yoshihiro; Haga, Yoshinori; Bernhoeft, N.*; Lander, G. H.*; Tokiwa, Yoshifumi; Onuki, Yoshichika
Acta Physica Polonica B, 34(2, Part2), p.979 - 982, 2003/02
no abstracts in English
Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Nakashima, Miho*; Aoki, Dai*; Onuki, Yoshichika*; Hedo, Masato*; Uwatoko, Yoshiya*
Acta Physica Polonica B, 34(2), p.1239 - 1242, 2003/02
Uranium intermetallic compounds UX (X = Si, Ge, Sn, Pb) form a ariety of magnetic properties including Pauli paramagnetism in USi and UGe, spin fluctuations in USn and antiferromagnetism in UPb. Among them, UPb is an antiferromagnet below the N
el temperature 32 K with a large electronic specific heat = 110 mJ/K
mol. In this study we present the electrical resistivity measurement under high pressure up to 8 GPa. We found that at low pressure 
increases with increasing pressure. It has a maximum value 36 K at 3 GPa, then decreases with increasing pressure.In addition we observed an additional resistive anomaly followed by a steep decrease in resistivity below under pressure.The maximum pressure 8 GPa in the present study was not enough to suppress the antiferromagnetic transition.The critical pressure is estimated to be around 12 GPa.
Matsuda, Tatsuma; Haga, Yoshinori; Tokiwa, Yoshifumi; Andrei, G.; Yamamoto, Etsuji; Okubo, Tomoyuki*; Onuki, Yoshichika
Acta Physica Polonica B, 34(2), p.1071 - 1074, 2003/02
We have successfully grown a single crystal of uranium intermetallic compound URhGe. The temperature dependence of electrical resistivity shows highly anisotropic behavior. Two anomalies, which correspond to the magnetic ordering temperatures, were observed in the resistivity, magnetic susceptibility and specific heat measurements at 
= 30 K and 
=25 K. The magnetic susceptibility also shows a large uniaxial anisotropy with a magnetic easy-axis along the [010] direction.
-
phase diagrams of CeSb and CeBiOsakabe, Toyotaka; Hannan, A.*; Kawana, Daichi*; Kogi, Masafumi*; Kitazawa, Hideaki*
Acta Physica Polonica B, 34(2), p.1469 - 1472, 2003/02
no abstracts in English
Si under pressureAraki, Shingo; Nakashima, Miho*; Settai, Rikio*; Kobayashi, Tatsuo*; Onuki, Yoshichika
Acta Physica Polonica B, 34(2, Part1), p.439 - 442, 2003/02
no abstracts in English
