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Journal Articles

Hadronic Paschen-Back effect in charmonium

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

AIP Conference Proceedings 2130, p.050001_1 - 050001_8, 2019/07

We find a novel phenomenon induced by the interplay between a strong magnetic field and finite orbital angular momenta in hadronic systems, which is analogous to the Paschen-Back effect observed in the field of atomic physics. This effect allows the wave functions to drastically deform. We discuss anisotropic decay from the deformation as a possibility to measure the strength of the magnetic field in heavy-ion collision at LHC, RHIC and SPS, which has not experimentally been measured. As an example we investigate charmonia with finite orbital angular momentum in a strong magnetic field. We calculate the mass spectra and mixing rate. To obtain anisotropic wave functions, we apply the cylindrical Gaussian expansion method, where the Gaussian bases to expand the wave functions have different widths along transverse and longitudinal directions in the cylindrical coordinate.

Journal Articles

Research and development on membrane IS process for hydrogen production using solar heat

Odtsetseg, M.; Iwatsuki, Jin; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Ioka, Ikuo; Kubo, Shinji; Nomura, Mikihiro*; Yamaki, Tetsuya*; Sawada, Shinichi*; et al.

International Journal of Hydrogen Energy, 44(35), p.19141 - 19152, 2019/07

Journal Articles

Hadronic Paschen-Back effect in P-wave charmonia under strong magnetic fields

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

International Journal of Modern Physics; Conference Series (Internet), 49, p.1960002_1 - 1960002_6, 2019/07

The hadronic Paschen-Back effects in P-wave charmonia are analyzed using the constituent quark models in strong magnetic field.

Journal Articles

Nucleon and $$Delta$$ isobar in a strong magnetic field

Yakhshiev, U.*; Kim, H.-C.; Oka, Makoto

Physical Review D, 99(5), p.054027_1 - 054027_11, 2019/03

 Percentile:100(Astronomy & Astrophysics)

We investigate Skyrmion solution of the chiral Lagrangian with magnetic field. We find that the Skyrmion is deformed in the magnetic field and its mass increases accordingly. The nucleon and $$Delta$$ isobar states are considered in the Skyrme model.

Journal Articles

Hadronic Paschen-Back effect

Iwasaki, Sachio; Oka, Makoto; Suzuki, Kei*; Yoshida, Tetsuya*

Physics Letters B, 790, p.71 - 76, 2019/03

 Times Cited Count:1 Percentile:14.11(Astronomy & Astrophysics)

We find a novel phenomenon induced by the interplay between a strong magnetic field and finite orbital angular momenta in hadronic systems, which is analogous to the Paschen-Back effect observed in the field of atomic physics. This effect allows the wave functions to drastically deform. We discuss anisotropic decay from the deformation as a possibility to measure the strength of the magnetic field in heavy-ion collision at LHC, RHIC and SPS, which has not experimentally been measured. As an example we investigate charmonia with finite orbital angular momentum in a strong magnetic field. We calculate the mass spectra and mixing rate. To obtain anisotropic wave functions, we apply the cylindrical Gaussian expansion method, where the Gaussian bases to expand the wave functions have different widths along transverse and longitudinal directions in the cylindrical coordinate.

Journal Articles

Dynamic accommodation of internal stress and selection of crystallographic orientation relationship in pearlite

Amemiya, Yutaro*; Nakada, Nobuo*; Morooka, Satoshi; Kosaka, Makoto*; Kato, Masaharu*

Tetsu To Hagane, 105(2), p.314 - 323, 2019/02

 Percentile:100(Metallurgy & Metallurgical Engineering)

For deeper understanding of a dynamic accommodation mechanism of internal stress in pearlite originated from the lattice misfit between ferrite and cementite phases, the lattice parameter ratios of cementite were locally analyzed in detail by using the electron backscatter diffraction (EBSD) technique. The EBSD analysis has revealed that lattice parameter ratios of cementite lamellae obviously differ from those of spheroidized cementite particles, which demonstrates that pearlite has a certain amount of internal stress as long as it maintains lamellar structure. The internal stress in pearlite gradually decreased during isothermal holding at 923 K after pearlitic transformation due to interfacial atomic diffusion of iron atoms. However, comparing with theoretical values under Pitsch-Petch orientation relationship, it was understood that large amount of internal stress had been already accommodated upon pearlitic transformation by introduction of misfit dislocations and structural ledges on ferrite/cementite lamellar interfaces. That is, the internal stress of pearlite is dynamically reduced by two different processes; built-in accommodation upon pearlitic transformation and additional time-dependent relaxation after pearlitic transformation. On the other hand, EBSD analysis and neutron diffraction technique gave remarkably different lattice parameters of cementite. From this result, it is concluded that various crystallographic orientation relationships between ferrite and cementite coexist in pearlite. Furthermore, elastic strain energy analysis suggests that the invariant-line criterion on ferrite/cementite interface plays an important role for the selection of orientation relationships in pearlite.

Journal Articles

Further signatures to support the tetraquark mixing framework for the two light-meson nonets

Kim, H.*; Kim, K. S.*; Cheoun, M.-K.*; Jido, Daisuke*; Oka, Makoto

Physical Review D, 99(1), p.014005_1 - 014005_15, 2019/01

 Percentile:100(Astronomy & Astrophysics)

We investigate additional signatures to support the tetraquark mixing framework that has been recently proposed as a possible structure for the two nonets. We reexamine the mass ordering generated from the tetraquark nonets and show that this mass ordering is satisfied by the two nonets although the ordering in the heavy nonet is marginal. The marginal mass ordering can be regarded as another signature for tetraquarks because it can be explained partially by the hyperfine masses calculated from the tetraquark mixing framework. As a peculiar signature distinguished from the other approaches, we investigate the fall-apart coupling strengths into two vector mesons from our tetraquarks. Coupling strengths into the two-vector modes are found to enhance strongly in the heavy nonet while they are suppressed in the light nonet. The coupling ratios are found to be huge. This trend in the two-vector modes can provide another testing ground for the tetraquark mixing framework. Some experimental evidence related to the phenomena is discussed particularly from the resonances belonging to the heavy nonet.

Journal Articles

Radiative transitions of doubly charmed baryons in lattice QCD

Bartiyar, H.*; Can, K. U.*; Erkol, G.*; Oka, Makoto; Takahashi, Toru*

Physical Review D, 98(11), p.114505_1 - 114505_14, 2018/12

 Times Cited Count:2 Percentile:64.74(Astronomy & Astrophysics)

Transition amplitude of spin 3/2 double-charm baryon to spin 1/2 ground state was evaluated in the lattice QCD, the first principle.

Journal Articles

Enhancement of Fe-N-C carbon catalyst activity for the oxygen reduction reaction; Effective increment of active sites by a short and repeated heating process

Yasuda, Satoshi; Uchibori, Yosuke*; Wakeshima, Makoto*; Hinatsu, Yukio*; Ogawa, Hiroaki; Yano, Masahiro; Asaoka, Hidehito

RSC Advances (Internet), 8(66), p.37600 - 37605, 2018/11

 Times Cited Count:1 Percentile:61(Chemistry, Multidisciplinary)

We present a quantitative study on the effect of a newly obtained thermal history on the formation of Fe-N-C catalytic sites. A short and repeated heating process is employed as the new thermal history, where short heating (1 min) followed by quenching is applied to a sample with arbitrary repetition. Through electrochemical quantitative analysis, it is found that the new process effectively increases the Fe-N-C mass-based site density (MSD) to almost twice that achieved using a conventional continuous heating process, while the turn-over frequency (TOF) is independent of the process. Elemental analysis shows that the new process effectively suppresses the thermal desorption of Fe and N atoms during the initial formation stage and consequently contributes to an increase in the Fe-N-C site density. The resultant catalytic activity (gravimetric kinetic current density (0.8 V vs. RHE)) is 1.8 times higher than that achieved with the continuous heating process.

Journal Articles

Quark model estimate of hidden-charm pentaquark resonances

Hiyama, Emiko; Hosaka, Atsushi; Oka, Makoto; Richard, J.-M.*

Physical Review C, 98(4), p.045208_1 - 045208_8, 2018/10

 Times Cited Count:2 Percentile:28.07(Physics, Nuclear)

A quark model, which reproduces the ground-state mesons and baryons, i.e., the threshold energies, is applied to the $$qqqcbar c$$ configurations, where $$q$$ is a light quark and $$c$$ the charmed quark. In the calculation, several open channels are explicitly included such as $$J/psi +N$$, $$eta_c+N$$, $$Lambda_c +D$$, etc. To distinguish genuine resonances and estimate their width, we employ Gaussian Expansion Method supplemented by the real scalingmethod (stabilization). No resonance is found at the energies of the $$P_c(4380)$$ and $$P_c(4450)$$ pentaquarks. On the other hand, there is a sharp resonant state at 4690 MeV with $$J=1/2^-$$ state and another one at 4920 MeV with $$J=3/2^-$$ state, which have a compact structure.

Journal Articles

Resonance states in the $$Y_cN$$ potential model

Maeda, Saori*; Oka, Makoto; Liu, Y.-R.*

Physical Review C, 98(3), p.035203_1 - 035203_9, 2018/09

 Times Cited Count:1 Percentile:49.68(Physics, Nuclear)

We calculate two-body $$J^{pi}=0^{+}, 1^{+}$$, and $$J^{pi}=2^{+}$$ resonance states of $$Y_{c}$$ ($$= Lambda_{c}$$, $$Sigma_{c}$$, or $$Sigma_{c}^{*}$$) and $$N$$ using the complex scaling method. We employ the $$Y_{c}N$$-CTNN potentials, which were proposed in our previous study, and obtain four resonances near $$Sigma_{c}N$$ and $$Sigma_{c}^{*}N$$ thresholds. From the analysis by the binding energies of partial channel systems, we conclude that these resonance states are Feshbach resonances. We compare the results with the $$Y_{c}N$$ resonance states in the heavy quark limit, where the $$Sigma_{c}N$$ and $$Sigma_{c}^{*}N$$ thresholds are degenerate, and find that they form two pairs of the heavy-quark doublets in agreement with the heavy quark spin symmetry.

Journal Articles

Nonperturbative evaluation for anomalous dimension in 2-dimensional $$O$$(3) sigma model

Jimmenez, S.*; Oka, Makoto; Sasaki, Kiyoshi*

Physical Review D, 97(11), p.114506_1 - 114506_28, 2018/06

 Percentile:100(Astronomy & Astrophysics)

We nonperturbatively calculate the wave-function renormalization in the two-dimensional $$O$$(3) sigma model. It is evaluated in a box with a finite spatial extent. We determine the anomalous dimension in the finite-volume scheme through an analysis of the step-scaling function. Results are compared with a perturbative evaluation, and reasonable behavior is observed.

Journal Articles

Tetraquark mixing framework for isoscalar resonances in light mesons

Kim, H.*; Kim, K. S.*; Cheoun, M.-K.*; Oka, Makoto

Physical Review D, 97(9), p.094005_1 - 094005_17, 2018/05

 Times Cited Count:5 Percentile:17.57(Astronomy & Astrophysics)

A tetraquark mixing framework has been applied successfully to the isoscalar resonances, $$f_0(500)$$, $$f_0(980)$$, $$f_0(1370)$$ and $$f_0(1500)$$. Tetraquarks in this framework can have two spin configurations containing either spin-0 diquark or spin-1 diquark and each configuration forms a nonet in flavor space. The two spin configurations are found to mix strongly through the color-spin interactions. Their mixtures, which diagonalize the hyperfine masses, can generate the physical resonances constituting two nonets, which, in fact, coincide roughly with the experimental observation. We identify that $$f_0(500)$$, $$f_0(980)$$ are the isoscalar members in the light nonet, and $$f_0(1370)$$, $$f_0(1500)$$ are the similar members in the heavy nonet. The complication arises because the isoscalar members of each nonet are subject to an additional flavor mixing known as Okubo-Zweig-Iizuka rule. The tetraquark mixing framework including the flavor mixing is tested for the isoscalar resonances in terms of the mass splitting and the fall-apart decay modes. The mass splitting among the isoscalar resonances is found to be consistent qualitatively with their hyperfine mass splitting strongly driven by the spin configuration mixing, which suggests that the tetraquark mixing framework works. The fall-apart modes from our tetraquarks also seem to be consistent with the experimental modes. We also discuss possible existence of the spin-1 tetraquarks that can be constructed by the spin-1 diquark.

Journal Articles

Charmonium ground and excited states at finite temperature from complex Borel sum rules

Araki, Kenji*; Suzuki, Kei*; Gubler, P.; Oka, Makoto

Physics Letters B, 780, p.48 - 53, 2018/05

 Times Cited Count:1 Percentile:49.68(Astronomy & Astrophysics)

Charmonium spectral functions in vector and pseudoscalar channels at finite temperature are investigated through the complex Borel sum rules and the maximum entropy method. Our approach enables us to extract the peaks corresponding to the excited charmonia, as well as those of the ground states, which has never been achieved in usual QCD sum rule analyses. We show the spectral functions in vacuum and their thermal modification around the critical temperature, which leads to the almost simultaneous melting (or peak disappearance) of the ground and excited states.

Journal Articles

Flavor-singlet hidden charm pentaquark

Irie, Yoya*; Oka, Makoto; Yasui, Shigehiro*

Physical Review D, 97(3), p.034006_1 - 034006_12, 2018/02

 Times Cited Count:1 Percentile:64.74(Astronomy & Astrophysics)

One type of hidden charm pentaquark $$P_{cs}$$ with quark content $$cbar c uds$$ in light-flavor singlet state is studied in the quark model. This state is analogous to the $$P_c$$ with $$cbar c uud$$ in light-flavor octet, which was observed in LHC in 2015. Considering various combinations of color, spin, and light flavor as internal quantum numbers in $$P_{cs}$$, we investigate the mass ordering of the $$P_{cs}$$'s by adopting both the one-gluon exchange interaction and the instanton-induced interaction in the quark model. The most stable configuration of $$P_{cs}$$ is identified to be total spin 1/2 in which the $$cbar c$$ is combined to be color octet and spin 1, while the uds cluster is in a color octet state. The other color octet configurations, the total spin $$1/2$$ state with the $$cbar c$$ spin 0, and the state with total spin $$3/2$$ and $$cbar c$$ spin 1, are found as excited states. We also discuss possible decay modes of these hidden charm pentaquarks.

Journal Articles

$$Xi_c gamma rightarrowXi^prime_c$$ transition in lattice QCD

Bahtlyar, H.*; Can, K. U.*; Erkol, G.*; Oka, Makoto; Takahashi, Toru*

Physics Letters B, 772, p.121 - 126, 2017/09

 Times Cited Count:8 Percentile:11.96(Astronomy & Astrophysics)

We evaluate the electromagnetic $$Xi_c gamma rightarrowXi_c^prime$$ transition on 2+1 flavor lattices corresponding to a pion mass of $$sim 156$$ MeV. We extract the magnetic Sachs and Pauli form factors which give the $$Xi_c$$-$$Xi_c^prime$$ transition magnetic moment and the decay rates of $$Xi_c^prime$$ baryons. We did not find a signal for the magnetic form factor of the neutral transition $$Xi_c^0 gamma rightarrowXi_c^{prime 0}$$, which is suppressed by the U-spin flavor symmetry. As a byproduct, we extract the magnetic form factors and the magnetic moments of $$Xi_c$$ and $$Xi_c^prime$$ baryons, which give an insight to the dynamics of $$u/d$$, $$s$$ and $$c$$ quarks having masses at different scales.

Journal Articles

Theoretical study of the $$Xi(1620)$$ and $$Xi(1690)$$ resonances in $$Xi_c to pi+MB$$ decays

Miyahara, Kenta*; Hyodo, Tetsuo*; Oka, Makoto; Nieves, J.*; Oset, E.*

Physical Review C, 95(3), p.035212_1 - 035212_12, 2017/03

 Times Cited Count:10 Percentile:8.11(Physics, Nuclear)

Nonleptonic weak decays of $$Xi_c$$ into $$pi^+$$ and a meson-baryon final state, $$MB$$, are analyzed from the viewpoint of probing $$S=-2$$ baryon resonances, i.e. $$Xi (1620)$$ and $$Xi (1690)$$. We argue that the weak decay of $$Xi_c$$ is dominated by a single quark-line diagram. The decay process has an advantage of being free from meson resonances in the $$pi+M$$ invariant mass distribution. The invariant mass distribution of the meson-baryon final state is calculated, assuming that the $$Xi (1620)$$ and $$Xi (1690)$$ resonances have $$J^P = 1/2^-$$. It is found that a clear peak for the $$Xi(1690)$$ is seen in the $$pi Xi$$ and $$K^-Lambda$$ spectra. We also suggest that the ratios of the $$pi Xi$$, $$K^-Lambda$$ and $$K^-Sigma$$ final states are useful to distinguish whether the peak is originated from the $$Xi (1690)$$ resonance or it is a $$K^- Sigma$$ threshold effect.

Journal Articles

Structure of charmed baryons studied by pionic decays

Nagahiro, Hideko*; Yasui, Shigehiro*; Hosaka, Atsushi; Oka, Makoto; Noumi, Hiroyuki*; Noumi, Hiroyuki*

Physical Review D, 95(1), p.014023_1 - 014023_20, 2017/01

 Times Cited Count:18 Percentile:7.82(Astronomy & Astrophysics)

We investigate the decays of the charmed baryons aiming at the systematic understanding of hadron internal structures based on the quark model by paying attention to heavy quark symmetry. We evaluate the decay widths from the one pion emission for the known excited states, $$Lambda^*_c(2595)$$, $$Lambda^*_c(2625)$$, $$Lambda^*_c(2765)$$, $$Lambda^*_c (2880)$$ and $$Lambda^*_c(2940)$$, as well as for the ground states $$Sigma_c(2455)$$ and $$Sigma^*_c(2520)$$. The calculated decay widths are in good agreement with the experimental data, and several important predictions for higher excited $$Lambda^*_c$$ baryons are given. We also find that the axial-vector type coupling of the pion to the light quarks is essential, which is expected from chiral symmetry, to reproduce the decay widths especially of the low lying $$Lambda^*_c$$ baryons. We emphasize the importance of the branching ratios of $$Gamma(Sigma^*_c pi)/Gamma(Sigma_c pi)$$ for the study of the nature of higher excited $$Lambda^*_c$$ baryons.

Journal Articles

Flavor structure of $$Lambda$$ baryons from lattice QCD; From strange to charm quarks

Gubler, P.*; Takahashi, Toru*; Oka, Makoto

Physical Review D, 94(11), p.114518_1 - 114518_16, 2016/12

 Percentile:100(Astronomy & Astrophysics)

JAEA Reports

Design study for impermeable function of trench disposal facility for very low level waste generated from research, industrial and medical facilities (Joint research)

Sakai, Akihiro; Kurosawa, Ryohei*; Nakata, Hisakazu; Okada, Shota; Izumo, Sari; Sato, Makoto*; Kitamura, Yoichi*; Honda, Yasutake*; Takaoka, Katsuki*; Amazawa, Hiroya

JAEA-Technology 2016-019, 134 Pages, 2016/10

JAEA-Technology-2016-019.pdf:8.25MB

Japan Atomic Energy Agency has been developing to design trench disposal facility with impermeable layers in order to dispose of miscellaneous waste. Geomembrane liners have a function that prevent seepage of leachant and collect the leachant. However, the geomembrane liners do not necessarily provide the expected performance due to damage generated when heavy equipment contacts with the liner. Therefore, we studied the impermeable layers having high performance of preventing seepage of leachant including radioactivity taking into account characteristics of low permeable materials and effect of multiple layer structure. As results, we have evaluated that the composite layers composed by a drainage layer, geomembrane liners and a low permeable layer are most effective structure to prevent seepage of leachant. Taking into account disposal of waste including cesium, we also considered zeolite containing sheets for adsorption of cesium were installed in the impermeable layers.

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