Intruder configurations in Ne at the transition into the island of inversion; Detailed structure study of Ne

Wang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.

Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08

https://doi.org/10.1016/j.physletb.2023.138038

Detailed -ray spectroscopy of the exotic neon isotope Ne has been performed using the one-neutron removal reaction from Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

Large-eddy simulation of plume dispersion in the central district of Oklahoma City by coupling with a mesoscale meteorological simulation model and observation

Nakayama, Hiromasa; Takemi, Tetsuya*; Yoshida, Toshiya

Atmosphere (Internet), 12(7), p.889_1 - 889_15, 2021/07

https://doi.org/10.3390/atmos12070889

Contaminant gas dispersion within urban area resulting from accidental or intentional release is of great concern to public health and social security. When estimating plume dispersion in a built-up urban area under real meteorological conditions by computational fluid dynamics (CFD), a crucial issue is how to prescribe the model input conditions. There are typically two approaches: using the outputs of a meso-scale meteorological simulation (MMS) model and meteorological observations (OBS). However, the influence of the different approaches on the simulation results have not been fully demonstrated. In this study, we conducted large-eddy simulations (LESs) of plume dispersion in the urban central district under real meteorological conditions by coupling with a MMS model and OBS obtained at a single stationary point, and evaluated the two different coupling simulations in comparison with the field experimental data. The LES-MMS coupling showed better performance than the LES-OBS one. However, the latter one also showed a reasonable performance comparable to the acceptance criteria on the model prediction within a factor of two of the experimental data. These facts indicate that the approach of using observations at a single stationary point still has enough potential to drive CFD models for plume dispersion under real meteorological conditions.

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

https://doi.org/10.1063/1.5118418

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.

Hadronic Paschen-Back effect

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

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

https://doi.org/10.1016/j.physletb.2018.10.024

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.

Production and decay of charmed baryons

Hosaka, Atsushi; Hiyama, Emiko; Kim, S.-H.*; Kim, H.-C.*; Nagahiro, Hideko*; Noumi, Hiroyuki*; Oka, Makoto; Shirotori, Kotaro*; Yoshida, Tetsuya*; Yasui, Shigehiro*

Nuclear Physics A, 954, p.341 - 351, 2016/10

https://doi.org/10.1016/j.nuclphysa.2016.05.009

In this paper, we discuss reactions involving charmed baryons to explore their unique features. A well known phenomenon, the separation of the two internal motions of the and types of a three-quark system is revisited. First we discuss the mass spectrum of low-lying excitations as functions of the heavy quark mass, smoothly connecting the and heavy quark limits. The properties of these modes can be tested in the production and decay reactions of the baryons. For the productions, we consider a one step process which excites dominantly mode excitations. We find abundant production rates for some of excited states. For decays, we study pion emission process, which provides a clean tool to test the structure of heavy quark systems due to well controlled low energy dynamics of the pion and quark. Both productions and decays of the charmed baryons are the issues of the future experiments at J-PARC.

Spectrum of heavy baryons in the quark model

Yoshida, Tetsuya*; Hiyama, Emiko*; Hosaka, Atsushi*; Oka, Makoto; Sadato, Katsunori*

Physical Review D, 92(11), p.114029_1 - 114029_19, 2015/12

https://doi.org/10.1103/PhysRevD.92.114029

Single- and double-heavy baryons are studied in the constituent quark model. The model Hamiltonian is chosen as a standard one with two exceptions: (1) the color-Coulomb term depends on quark masses and (2) an antisymmetric (spin-orbit) force is introduced. Model parameters are fixed by the strange baryon spectra, and baryons. The masses of the observed charmed and bottomed baryons are, then, fairly well reproduced. Our focus is on the low-lying negative-parity states, in which the heavy baryons show specific excitation modes reflecting the mass differences of heavy and light quarks. By changing quark masses from the SU(3) limit to the strange quark mass, and, further, to the charm and bottom quark masses, we demonstrate that the spectra change from the SU(3) symmetry patterns to the heavy-quark-symmetry ones.

Numerical simulation of self-priming phenomena in venturi scrubber by two-phase flow simulation code TPFIT

Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05

From the viewpoint of protecting containment and suppressing diffusion of the radioactive materials at severe accidents of nuclear power plant, it is important to install filtered venting devices to permit release of high pressure pollutant gas to the atmosphere by eliminating radioactive materials in the gas. A Multi Venturi Scrubber System (MVSS) is one of the devices for the filtered venting, and is used to realize filtered venting without any power supply. The MVSS is composed of a "Venturi Scrubbers" part and a "bubble column" part. In the Venturi Scrubbers part of the MVSS, there are hundreds of the Venturi scrubbers (VS). In an operation mode of the MVSS, the radioactive materials are eliminated through the gas-liquid interface from the pollutant gas to the liquid phase of a dispersed flow in the VS and a bubbly flow in the bubble column part. In the VS, the dispersed flow is formed from the liquid, which is suctioned through the hole for suction (called self-priming). In previous studies, an evaluation method to evaluate the liquid flow rate by the self-priming was developed. However, to develop evaluation methods of performance of the VSs, the two-phase flow behavior must be investigated, including droplet size and velocity difference of liquid and gas phases. Two-phase flow behavior in the VS is complicated, and it is difficult to estimate two-phase flow behavior of the VS by only experimental procedures. In this study, to investigate the hydraulic behavior of the VS, we tried to apply a detailed numerical simulation method of two-phase flow to the numerical simulation of the VS. In the simulation, TPFIT developed in JAEA was used as the detailed numerical simulation method. In this paper, we performed the numerical simulation air-water two-phase flow in the of the lab scale VS by the TPFIT, and numerical results were compared with experimental results.

Development of evaluation method of liquid flow rate by self-priming phenomena in venturi scrubber

Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*

Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 5 Pages, 2014/11

Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application

Kashiwagi, Mieko; Umeda, Naotaka; Tobari, Hiroyuki; Kojima, Atsushi; Yoshida, Masafumi; Taniguchi, Masaki; Dairaku, Masayuki; Maejima, Tetsuya; Yamanaka, Haruhiko; Watanabe, Kazuhiro; et al.

Review of Scientific Instruments, 85(2), p.02B320_1 - 02B320_3, 2014/02

https://doi.org/10.1063/1.4852297

The negative ion extractor for high power and long-pulse operations is newly developed toward the neutral beam injector (NBI) for heating & current drive of future fusion machines such as ITER, JT-60 Super Advanced (SA) and DEMO reactor. The satisfactory cooling capability is designed in the thermal analysis. A negative ion production and a suppression of electrons are experimentally validated for this new extractor. As the results, the negative ion current shows increases by a factor of 1.3 with suppressing the electron current. The beam divergence angle is also maintained small enough, 4 mrad.

Mechanism of synthesis of metallic oxide powder from aqueous metallic nitrate solution by microwave denitration method

Fukui, Kunihiro*; Igawa, Yusuke*; Arimitsu, Naoki*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi*; Yamamoto, Tetsuya*; Yoshida, Hideto*

Chemical Engineering Journal, 211-212, p.1 - 8, 2012/11

https://doi.org/10.1016/j.cej.2012.09.032

The process for synthesizing metallic oxide powders by the microwave denitration method was investigated using hexahydrated nickel nitrate and trihydrated copper nitrate aqueous solutions, and the electrical field and the temperature distributions in the reactor were numerically simulated. Although CuO powder can be obtained from a trihydrated copper nitrate aqueous solution by the microwave denitration method, a hexahydrated nickel nitrate aqueous solution cannot be heated up to over 270 C by microwave irradiation. It was also found that the reaction routes for microwave heating are the same as those for conventional external heating. This finding indicates that the success of producing oxide particles by microwave denitration depends not only on the microwave absorptivity of the intermediate and the metallic oxide, but also on the temperature difference.