The authors have studied the ground-state properties (nuclear radii, binding energies and density... more The authors have studied the ground-state properties (nuclear radii, binding energies and density distributions) of light neutron-rich nuclei within the Hartree-Fock approximation using Skyrme interactions. The experimental mass-number dependences of the nuclear radii of He isotopes and the binding energies of He, Be, C and O isotopes are well reproduced by calculations for all isotopes except 4He and 8Be. The SIII, having the symmetry energy coefficient atau =28.3 MeV, works better than other forces with larger symmetry energies for describing neutron-rich light nuclei. They find the results of the Hartree-Fock calculations show that 18,20,22C and 24O are stable against emission of two neutrons.
The gamma-ray production in neutral-current (NC) neutrino-oxygen interaction is very important to... more The gamma-ray production in neutral-current (NC) neutrino-oxygen interaction is very important to the detection of neutrinos from supernova explosion in a neutrino experiment using water target like Super-K, since those gamma-rays can become extra signals or unexpected background in the energy region from 5 MeV to 30 MeV. We discuss a possible experiment to measure gamma-rays in 16O(p, p') and 16O(3He, t) reactions at Research Center for Nuclear Physics (RCNP, Osaka). Such measurements should provide good information on the gamma-ray emission spectra in neutrino-oxygen reactions.
We calculate the relative absorption ratio of a pion by T = 0 and T = 1 nucleon pairs in the He i... more We calculate the relative absorption ratio of a pion by T = 0 and T = 1 nucleon pairs in the He isotopes measured recently by Ashery et al. Standard theory based on A-isobar intermediate excitations agrees with the experimental observation that for energies around the resonance, pion absorption by a T = 1 nucleon pair is strongly suppressed.
ABSTRACT We study theoretically the ground state properties of the Sr isotopes with A = 78 throug... more ABSTRACT We study theoretically the ground state properties of the Sr isotopes with A = 78 through 100 within the relativistic mean field (RMF) theory. We make constraint calculations of the ground state energies as a function of the β deformation. We find several minima in the energy curve for each nucleus. We discuss the ground state deformation in terms of the spin of the odd mass nucleus and the quadrupole moments. In accordance with experimental observation, we can also explain the sudden increase of isotope shifts at A = 98 by a change to a configuration with large prolate deformation. Both the mass number dependence of the binding energies per particle and the charge radii are reproduced reasonably well.
Numerical results have been obtained for calculations of pion double charge exchange arising from... more Numerical results have been obtained for calculations of pion double charge exchange arising from A33mediated processes. Calculations of double-charge-exchange excitation functions and angular distributions are presented for the reaction O(n. +, n)' Ne(g. s.). The sensitivity of the calculations to quantities specifying the reaction mechanism is shown. The large cross sections and simple systematics of pion double charge exchange (DCX) on T = 0 targets'2 are among the most surprising features of DCX. The systematics' of these 5 'r= 2, 5J =0 transitions (excitation functions
We study the angular distributions of low energy protons for various multiplicity cuts in EL=0.8 ... more We study the angular distributions of low energy protons for various multiplicity cuts in EL=0.8 GeV/nucleon heavy nuclear collisions in terms of the nuclear cascade model. The differential cross sections for low energy protons (Ec<100 MeV, with Ec being the proton energy in the center-of-mass frame) in the lateral direction move up relatively with respect to those in the forward direction as the multiplicity cut increases. For the case of La+La collisions, for example, the differential cross section becomes maximum at thetac=90° above the multiplicity cut M>60.
The semi-decoupled model, which was proposed in a previous publication with the aim of describing... more The semi-decoupled model, which was proposed in a previous publication with the aim of describing the frequently appearing odd parity bands in even nuclei with spin sequence Al-2, is extended to the case of a y-deformed core. The extended model is applied in a cal culation of the yrast odd parity states of the even Pt and Hg isotopes, assuming respectively y-30°and y-60°for the two elements. Characteristic diffo between the appearance of the odd parity bands of the two elements are well accounted for by the model and may be understood in terms of simple qualitative features of the model system. An explanation of the 10isomers observed in 190-r 9'Pt is also provided by the model .
Abstract G-matrix elements for finite nuclei are calculated using effective masses for mesons and... more Abstract G-matrix elements for finite nuclei are calculated using effective masses for mesons and nucleons at finite density, i.e., those in nuclear medium. We find that the central G-matrix elements are very sensitive to masses of the sigma and omega. By decreasing the mass of the rho, the LS matrix elements are generally enhanced, while the tensor matrix elements are suppressed. A uniform decrease in various masses yields G-matrix elements which are rather consistent with empirical matrix elements obtained by Brown, Richter, Julies and Wildenthal.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
Abstract We discuss the use of (d, 3 He) reactions with inverse kinematics for high-resolution sp... more Abstract We discuss the use of (d, 3 He) reactions with inverse kinematics for high-resolution spectroscopy of pion bound states
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008
The WASA 4π multidetector system, aimed at investigating light meson production in light ion coll... more The WASA 4π multidetector system, aimed at investigating light meson production in light ion collisions and η meson rare decays at the CELSIUS storage ring in Uppsala is presented. A detailed description of the design, together with the anticipated and achieved performance parameters are given.
The nature of the ground and the ~ band is studied in the asymmetric rotator model for larger asy... more The nature of the ground and the ~ band is studied in the asymmetric rotator model for larger asymmetric deformations 7 and higher angular momenta. Properties of the ~ band are found which may make it possible to search experimentally for static deformations. Sum rules for quadrupole moments and energies are derived. For the description of higher angular momenta the softness of the nucleus is included by an extension of the VMI model to asymmetric deformations. Energies, quadrupole moments and E2 transitions are given for the Os region and compared with the available data.
Low spin states (J < j) for transitional nuclei with a typical decoupling spectrum built on a ... more Low spin states (J < j) for transitional nuclei with a typical decoupling spectrum built on a single particle level j show systematic discrepancies between theory and experiment. To account for the discrepancies the decoupling scheme is extended to include also strong coupling. Excellent agreement including that for the low spin states is found in 187Ir to which this theory is applied.
Abstract The γ-ray production in neutral-current neutrino-oxygen interaction is very important to... more Abstract The γ-ray production in neutral-current neutrino-oxygen interaction is very important to neutrino experiment using water target, since those γ-rays can produce extra signals or unexpected background in the energy region from 5 to 30 MeV. We propose to measure γ-rays in O 16 ( p , p ′ ) and O 16 ( He 3 , t ) reactions at Reseach Center for Nuclear Physics.
Proceedings of The IX International Conference on Hypernuclear and Strange Particle Physics
We briefly review the experiments of KEK and FINUDA, that claim evidence for deeply bound kaon st... more We briefly review the experiments of KEK and FINUDA, that claim evidence for deeply bound kaon states, from the perspective of recent theoretical papers and experiments that provide an alternative explanation of the peaks seen. At the same time we show that recent criticisms raised by Akaishi and Yamazaki, and exposed by Akaishi in this Conference, have no base.
We study pion-nucleus elastic scattering in the GeV region within the Glauber theory. For the use... more We study pion-nucleus elastic scattering in the GeV region within the Glauber theory. For the use of the forward multiple scattering approximation, the pion-nucleon scattering amplitude is parametrized in the Gaussian form. The calculated results are compared very well with the 12C and 4DCa data at the laboratory momentum of k=O.8 GeV /C.
The authors have studied the ground-state properties (nuclear radii, binding energies and density... more The authors have studied the ground-state properties (nuclear radii, binding energies and density distributions) of light neutron-rich nuclei within the Hartree-Fock approximation using Skyrme interactions. The experimental mass-number dependences of the nuclear radii of He isotopes and the binding energies of He, Be, C and O isotopes are well reproduced by calculations for all isotopes except 4He and 8Be. The SIII, having the symmetry energy coefficient atau =28.3 MeV, works better than other forces with larger symmetry energies for describing neutron-rich light nuclei. They find the results of the Hartree-Fock calculations show that 18,20,22C and 24O are stable against emission of two neutrons.
The gamma-ray production in neutral-current (NC) neutrino-oxygen interaction is very important to... more The gamma-ray production in neutral-current (NC) neutrino-oxygen interaction is very important to the detection of neutrinos from supernova explosion in a neutrino experiment using water target like Super-K, since those gamma-rays can become extra signals or unexpected background in the energy region from 5 MeV to 30 MeV. We discuss a possible experiment to measure gamma-rays in 16O(p, p') and 16O(3He, t) reactions at Research Center for Nuclear Physics (RCNP, Osaka). Such measurements should provide good information on the gamma-ray emission spectra in neutrino-oxygen reactions.
We calculate the relative absorption ratio of a pion by T = 0 and T = 1 nucleon pairs in the He i... more We calculate the relative absorption ratio of a pion by T = 0 and T = 1 nucleon pairs in the He isotopes measured recently by Ashery et al. Standard theory based on A-isobar intermediate excitations agrees with the experimental observation that for energies around the resonance, pion absorption by a T = 1 nucleon pair is strongly suppressed.
ABSTRACT We study theoretically the ground state properties of the Sr isotopes with A = 78 throug... more ABSTRACT We study theoretically the ground state properties of the Sr isotopes with A = 78 through 100 within the relativistic mean field (RMF) theory. We make constraint calculations of the ground state energies as a function of the β deformation. We find several minima in the energy curve for each nucleus. We discuss the ground state deformation in terms of the spin of the odd mass nucleus and the quadrupole moments. In accordance with experimental observation, we can also explain the sudden increase of isotope shifts at A = 98 by a change to a configuration with large prolate deformation. Both the mass number dependence of the binding energies per particle and the charge radii are reproduced reasonably well.
Numerical results have been obtained for calculations of pion double charge exchange arising from... more Numerical results have been obtained for calculations of pion double charge exchange arising from A33mediated processes. Calculations of double-charge-exchange excitation functions and angular distributions are presented for the reaction O(n. +, n)' Ne(g. s.). The sensitivity of the calculations to quantities specifying the reaction mechanism is shown. The large cross sections and simple systematics of pion double charge exchange (DCX) on T = 0 targets'2 are among the most surprising features of DCX. The systematics' of these 5 'r= 2, 5J =0 transitions (excitation functions
We study the angular distributions of low energy protons for various multiplicity cuts in EL=0.8 ... more We study the angular distributions of low energy protons for various multiplicity cuts in EL=0.8 GeV/nucleon heavy nuclear collisions in terms of the nuclear cascade model. The differential cross sections for low energy protons (Ec<100 MeV, with Ec being the proton energy in the center-of-mass frame) in the lateral direction move up relatively with respect to those in the forward direction as the multiplicity cut increases. For the case of La+La collisions, for example, the differential cross section becomes maximum at thetac=90° above the multiplicity cut M>60.
The semi-decoupled model, which was proposed in a previous publication with the aim of describing... more The semi-decoupled model, which was proposed in a previous publication with the aim of describing the frequently appearing odd parity bands in even nuclei with spin sequence Al-2, is extended to the case of a y-deformed core. The extended model is applied in a cal culation of the yrast odd parity states of the even Pt and Hg isotopes, assuming respectively y-30°and y-60°for the two elements. Characteristic diffo between the appearance of the odd parity bands of the two elements are well accounted for by the model and may be understood in terms of simple qualitative features of the model system. An explanation of the 10isomers observed in 190-r 9'Pt is also provided by the model .
Abstract G-matrix elements for finite nuclei are calculated using effective masses for mesons and... more Abstract G-matrix elements for finite nuclei are calculated using effective masses for mesons and nucleons at finite density, i.e., those in nuclear medium. We find that the central G-matrix elements are very sensitive to masses of the sigma and omega. By decreasing the mass of the rho, the LS matrix elements are generally enhanced, while the tensor matrix elements are suppressed. A uniform decrease in various masses yields G-matrix elements which are rather consistent with empirical matrix elements obtained by Brown, Richter, Julies and Wildenthal.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991
Abstract We discuss the use of (d, 3 He) reactions with inverse kinematics for high-resolution sp... more Abstract We discuss the use of (d, 3 He) reactions with inverse kinematics for high-resolution spectroscopy of pion bound states
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008
The WASA 4π multidetector system, aimed at investigating light meson production in light ion coll... more The WASA 4π multidetector system, aimed at investigating light meson production in light ion collisions and η meson rare decays at the CELSIUS storage ring in Uppsala is presented. A detailed description of the design, together with the anticipated and achieved performance parameters are given.
The nature of the ground and the ~ band is studied in the asymmetric rotator model for larger asy... more The nature of the ground and the ~ band is studied in the asymmetric rotator model for larger asymmetric deformations 7 and higher angular momenta. Properties of the ~ band are found which may make it possible to search experimentally for static deformations. Sum rules for quadrupole moments and energies are derived. For the description of higher angular momenta the softness of the nucleus is included by an extension of the VMI model to asymmetric deformations. Energies, quadrupole moments and E2 transitions are given for the Os region and compared with the available data.
Low spin states (J < j) for transitional nuclei with a typical decoupling spectrum built on a ... more Low spin states (J < j) for transitional nuclei with a typical decoupling spectrum built on a single particle level j show systematic discrepancies between theory and experiment. To account for the discrepancies the decoupling scheme is extended to include also strong coupling. Excellent agreement including that for the low spin states is found in 187Ir to which this theory is applied.
Abstract The γ-ray production in neutral-current neutrino-oxygen interaction is very important to... more Abstract The γ-ray production in neutral-current neutrino-oxygen interaction is very important to neutrino experiment using water target, since those γ-rays can produce extra signals or unexpected background in the energy region from 5 to 30 MeV. We propose to measure γ-rays in O 16 ( p , p ′ ) and O 16 ( He 3 , t ) reactions at Reseach Center for Nuclear Physics.
Proceedings of The IX International Conference on Hypernuclear and Strange Particle Physics
We briefly review the experiments of KEK and FINUDA, that claim evidence for deeply bound kaon st... more We briefly review the experiments of KEK and FINUDA, that claim evidence for deeply bound kaon states, from the perspective of recent theoretical papers and experiments that provide an alternative explanation of the peaks seen. At the same time we show that recent criticisms raised by Akaishi and Yamazaki, and exposed by Akaishi in this Conference, have no base.
We study pion-nucleus elastic scattering in the GeV region within the Glauber theory. For the use... more We study pion-nucleus elastic scattering in the GeV region within the Glauber theory. For the use of the forward multiple scattering approximation, the pion-nucleon scattering amplitude is parametrized in the Gaussian form. The calculated results are compared very well with the 12C and 4DCa data at the laboratory momentum of k=O.8 GeV /C.
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Papers by H. Toki