Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.3
Toshio Suzuki, H. Sagawa
Sum rule, especially the energy-weighted sum rule (EWSR) of the spin-dipole transition strength is discussed, and the effects of the spin-orbit interaction as well as the kinetic energy term and the tensor interaction on the splitting and distribution of the strength are investigated. Light nuclei such as 12C and 16O are studied by shell-model calculations including up to 3ħω space while HF+TDA is used for an analysis of 208Bi. An application to neutral current neutrino scattering on 16O from supernovae heavy-flavor neutrinos is presented. For the Gamow-Teller mode, effects of quenching and fragmentation of the strength by coupling to 2p-2h configurations are shown to be important. How large or small is the quenching of the strength due to the Δþ contributions is also studied. As an isospin mode, isospin dependence of the spreading width of the isobaric analog state is analyzed and recent experimental data is shown to be well explained.
{"title":"Spin and isospin modes","authors":"Toshio Suzuki, H. Sagawa","doi":"10.1556/APH.13.2001.1-3.3","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.3","url":null,"abstract":"Sum rule, especially the energy-weighted sum rule (EWSR) of the spin-dipole transition strength is discussed, and the effects of the spin-orbit interaction as well as the kinetic energy term and the tensor interaction on the splitting and distribution of the strength are investigated. Light nuclei such as 12C and 16O are studied by shell-model calculations including up to 3ħω space while HF+TDA is used for an analysis of 208Bi. An application to neutral current neutrino scattering on 16O from supernovae heavy-flavor neutrinos is presented. For the Gamow-Teller mode, effects of quenching and fragmentation of the strength by coupling to 2p-2h configurations are shown to be important. How large or small is the quenching of the strength due to the Δþ contributions is also studied. As an isospin mode, isospin dependence of the spreading width of the isobaric analog state is analyzed and recent experimental data is shown to be well explained.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"11 1","pages":"11-19"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75747406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.5
U. Garg
Over the past few years, very good evidence has emerged for the Isoscalar Giant Dipole Resonance from small-angle inelastic scattering of α particles between 50–100 MeV/nucleon. A reconciliation between the available theoretical predictions and the experimental results still remains far from satisfactory, however, and there are interesting implications of the observed ISGDR strengths on the experimental determination of the incompressibility of nuclear matter. Some possible future measurements are also discussed.
{"title":"The Isoscalar Giant Dipole Resonance: Where we are and where we are headed","authors":"U. Garg","doi":"10.1556/APH.13.2001.1-3.5","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.5","url":null,"abstract":"Over the past few years, very good evidence has emerged for the Isoscalar Giant Dipole Resonance from small-angle inelastic scattering of α particles between 50–100 MeV/nucleon. A reconciliation between the available theoretical predictions and the experimental results still remains far from satisfactory, however, and there are interesting implications of the observed ISGDR strengths on the experimental determination of the incompressibility of nuclear matter. Some possible future measurements are also discussed.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"1 1","pages":"31-40"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84490184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.18
N. Itagaki, K. Ikeda, S. Okabe
The structure of 12Be is investigated using a microscopic α+α+4n model based on the molecular-orbit (MO) model. It is shown that the remark-able α-clustering and the contribution of the spin-orbit interaction make the binding of the state with the (3/2−)2(1/2+)2 configuration for the valence neutrons properly stronger in comparison with the closed p-shell (3/2−)2(1/2−)2 configuration. The molecular-like structure of the C isotopes is also investigated using a microscopic α+α+α+n+n+... model.
{"title":"Molecular-orbital structure in Be isotopes","authors":"N. Itagaki, K. Ikeda, S. Okabe","doi":"10.1556/APH.13.2001.1-3.18","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.18","url":null,"abstract":"The structure of 12Be is investigated using a microscopic α+α+4n model based on the molecular-orbit (MO) model. It is shown that the remark-able α-clustering and the contribution of the spin-orbit interaction make the binding of the state with the (3/2−)2(1/2+)2 configuration for the valence neutrons properly stronger in comparison with the closed p-shell (3/2−)2(1/2−)2 configuration. The molecular-like structure of the C isotopes is also investigated using a microscopic α+α+α+n+n+... model.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"44 1","pages":"153-156"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82775934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.25
I. Deloncle, S. Perriès, S. Courtin, N. Amzal, A. Chewter, T. Kröll, C. Petrache, W. Urban, E. Piasecki, A. Nowak, M. Houry, R. Cunningham, R. Herzberg, P. Butler, G. Duchêne, M. Porquet, A. Astier, A. Bauchet, B. Gall, N. Schulz, J. Duprat, N. Buforn, N. Redon, M. Meyer, R. Lucas, T. Venkova, F. Hoellinger
The 99−105Tc isotopes have been produced at high spin as fission fragments following the fusion reaction 37Cl(170 MeV) + 176Yb and studied with the Euroball3 array. The high-spin structures of 103Tc have been identified for the first time. From the systematics of the yrast states of 97−105Tc, the location of individual proton states can be analyzed as a function of the neutron number.
{"title":"High-Spin Structures of the Odd-A 97 - 105 43 Tc Isotopes","authors":"I. Deloncle, S. Perriès, S. Courtin, N. Amzal, A. Chewter, T. Kröll, C. Petrache, W. Urban, E. Piasecki, A. Nowak, M. Houry, R. Cunningham, R. Herzberg, P. Butler, G. Duchêne, M. Porquet, A. Astier, A. Bauchet, B. Gall, N. Schulz, J. Duprat, N. Buforn, N. Redon, M. Meyer, R. Lucas, T. Venkova, F. Hoellinger","doi":"10.1556/APH.13.2001.1-3.25","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.25","url":null,"abstract":"The 99−105Tc isotopes have been produced at high spin as fission fragments following the fusion reaction 37Cl(170 MeV) + 176Yb and studied with the Euroball3 array. The high-spin structures of 103Tc have been identified for the first time. From the systematics of the yrast states of 97−105Tc, the location of individual proton states can be analyzed as a function of the neutron number.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"48 1","pages":"189-191"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75938211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.4
A. Berg, H. Akimune, I. Daito, H. Fujimura, M. Fujiwara, Y. Fujita, M. Harakeh, F. Ihara, T. Inomata, K. Ishibashi, J. Jänecke, N. Kalantar-Nayestanaki, H. Laurent, I. Lhenry, H. V. D. Molen, T. O'Donnell, V. Rodin, A. Tamii, H. Toyokawa, M. H. Urin, H. Yoshida, M. Yosoi
Damping of high-lying single-particle states was investigated by the study of decay by proton emission from high-lying states in 91Nb, populated by the 90Zr(α, t) reaction at Eα=180 MeV. In addition to decay to the ground state of 90Zr, semi-direct decay was observed to the low-lying (2+/5− and 3−) phonon states, confirming the conclusion from other experiments that phonon states play an important role in the damping process of the single-particle states. Furthermore, the population and decay of isobaric analogue states of 91Zr, which are located at an excitation energy of about 10–12 MeV in 91Nb, has been studied in the same reaction.
{"title":"Collective and single-particle states at high excitation energy","authors":"A. Berg, H. Akimune, I. Daito, H. Fujimura, M. Fujiwara, Y. Fujita, M. Harakeh, F. Ihara, T. Inomata, K. Ishibashi, J. Jänecke, N. Kalantar-Nayestanaki, H. Laurent, I. Lhenry, H. V. D. Molen, T. O'Donnell, V. Rodin, A. Tamii, H. Toyokawa, M. H. Urin, H. Yoshida, M. Yosoi","doi":"10.1556/APH.13.2001.1-3.4","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.4","url":null,"abstract":"Damping of high-lying single-particle states was investigated by the study of decay by proton emission from high-lying states in 91Nb, populated by the 90Zr(α, t) reaction at Eα=180 MeV. In addition to decay to the ground state of 90Zr, semi-direct decay was observed to the low-lying (2+/5− and 3−) phonon states, confirming the conclusion from other experiments that phonon states play an important role in the damping process of the single-particle states. Furthermore, the population and decay of isobaric analogue states of 91Zr, which are located at an excitation energy of about 10–12 MeV in 91Nb, has been studied in the same reaction.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"67 1","pages":"21-30"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86030723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.17
I. Angeli
The nucleon number dependence of rms charge radii is often approximated by some simple formula containing the mass number only, R(A)=r(A)A1/3, where r(A) is a slowly varying function of A. However, for nuclei off the stability line, the mass number A=N + Z is not enough to characterise the dependence of the R(Z, N) radius surface on the nucleon numbers Z and N. In the present work, an additional term has been included, depending on the symmetry parameter I=(N − Z)/A. Several parametrisations were tried, using weighted least-squares procedures for the fit to a present-day data base. The best fit (with χ2/n=17) was found for R(A, I)=r(A)A1/3 + bI/(I − Istab), where Istab=(Nstab − Zstab)/A is the value of the symmetry parameter of the stable isobar with mass number A, and bI=−0.83 fm. The formula R(A, I)=[r(A) + aI(I − Istab)]A1/3 is only slightly inferior to the previous one, moreover, it is supported by simple model calculations; here aI=−0.20 fm (χ2/n=20). The difficulty in determining the right parametrisation is caused by the fact that the surface Rexp(A, I) is not smooth: there are strong shell and deformation effects. To avoid the distorting effect of these deviations on the parameter values, more than half of the original data had to be omitted.
{"title":"Symmetry dependence of rms Charge Radii","authors":"I. Angeli","doi":"10.1556/APH.13.2001.1-3.17","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.17","url":null,"abstract":"The nucleon number dependence of rms charge radii is often approximated by some simple formula containing the mass number only, R(A)=r(A)A1/3, where r(A) is a slowly varying function of A. However, for nuclei off the stability line, the mass number A=N + Z is not enough to characterise the dependence of the R(Z, N) radius surface on the nucleon numbers Z and N. In the present work, an additional term has been included, depending on the symmetry parameter I=(N − Z)/A. Several parametrisations were tried, using weighted least-squares procedures for the fit to a present-day data base. The best fit (with χ2/n=17) was found for R(A, I)=r(A)A1/3 + bI/(I − Istab), where Istab=(Nstab − Zstab)/A is the value of the symmetry parameter of the stable isobar with mass number A, and bI=−0.83 fm. The formula R(A, I)=[r(A) + aI(I − Istab)]A1/3 is only slightly inferior to the previous one, moreover, it is supported by simple model calculations; here aI=−0.20 fm (χ2/n=20). The difficulty in determining the right parametrisation is caused by the fact that the surface Rexp(A, I) is not smooth: there are strong shell and deformation effects. To avoid the distorting effect of these deviations on the parameter values, more than half of the original data had to be omitted.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"18 1","pages":"149-152"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84888479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.20
K. Ikeda, T. Myo, K. Katō, S. Aoyama
The Coulomb breakup reaction of 6He into a 4He+n+n 3-body system is analyzed by applying the complex scaling method (CSM). We can derive the contributions to El and E2 transitions, not only from resonances, but also 2- and 3-body continuum states, which show the characteristic structure of the many-body unbound states in 6He.
{"title":"Structure of light unstable nuclei in continuum energies","authors":"K. Ikeda, T. Myo, K. Katō, S. Aoyama","doi":"10.1556/APH.13.2001.1-3.20","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.20","url":null,"abstract":"The Coulomb breakup reaction of 6He into a 4He+n+n 3-body system is analyzed by applying the complex scaling method (CSM). We can derive the contributions to El and E2 transitions, not only from resonances, but also 2- and 3-body continuum states, which show the characteristic structure of the many-body unbound states in 6He.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"52 1","pages":"163-167"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83572845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.2
Hiroyuki Sagawa, Toshio Suzuki
We have studied dipole states of oxygen isotopes in large scale shell model calculations. The calculated photoreaction cross sections in 16O, 17O and 18O give reasonable agreement with experimental observations both in the low energy region below ħω=15 MeV and in the high energy giant resonance region (15 MeV < ħω ≤ 30 MeV). We found that the transition strength below dipole giant resonance (ħω ≤ 15 MeV) exhausts about 10% of the classical Thomas-Reiche-Kuhn sum rule and more than 40% of the cluster sum rule in heavier oxygen isotopes than 17O. The predicted Pigmy strengths in 20O and 22O are also confirmed by recent Coulomb excitation experiment at GSI.
{"title":"Pigmy and giant dipole states in stable and unstable oxygen isotopes","authors":"Hiroyuki Sagawa, Toshio Suzuki","doi":"10.1556/APH.13.2001.1-3.2","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.2","url":null,"abstract":"We have studied dipole states of oxygen isotopes in large scale shell model calculations. The calculated photoreaction cross sections in 16O, 17O and 18O give reasonable agreement with experimental observations both in the low energy region below ħω=15 MeV and in the high energy giant resonance region (15 MeV < ħω ≤ 30 MeV). We found that the transition strength below dipole giant resonance (ħω ≤ 15 MeV) exhausts about 10% of the classical Thomas-Reiche-Kuhn sum rule and more than 40% of the cluster sum rule in heavier oxygen isotopes than 17O. The predicted Pigmy strengths in 20O and 22O are also confirmed by recent Coulomb excitation experiment at GSI.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"25 1","pages":"3-9"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88394453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.27
L. Hernández, P. Hess, A. Algora, G. Lévai
The Be chain of isotopes is investigated within the Sernimicroscopic Algebraic Cluster Model (SACM). For that the SACM is extended to odd-mass p-shell nuclei. We show that the main features of the Be isotopes can be well explained. Though for the neutron halo nucleus 11Be some problems remain, the shell model still can describe the rough structures of these nuclei. In 11Be a shell inversion takesplace reflecting the high deformation of the system. The quadrupole—quadrupole interaction plays a dominant role in p-shell nuclei.
{"title":"α-clustering in Be isotopes","authors":"L. Hernández, P. Hess, A. Algora, G. Lévai","doi":"10.1556/APH.13.2001.1-3.27","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.27","url":null,"abstract":"The Be chain of isotopes is investigated within the Sernimicroscopic Algebraic Cluster Model (SACM). For that the SACM is extended to odd-mass p-shell nuclei. We show that the main features of the Be isotopes can be well explained. Though for the neutron halo nucleus 11Be some problems remain, the shell model still can describe the rough structures of these nuclei. In 11Be a shell inversion takesplace reflecting the high deformation of the system. The quadrupole—quadrupole interaction plays a dominant role in p-shell nuclei.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"528 1","pages":"197-198"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79639388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-03-01DOI: 10.1556/APH.13.2001.1-3.21
R. Suzuki, T. Myo, K. Katō, K. Ikeda
We investigate the low-energy spectrum of the one-neutron halo nucleus 11Be using the complex scaled coupled channel method for a 10Be + n model, paying attention to the effects of the deformation of the 10Be-core and the Pauli principle between the core and a valence neutron. For positive parity states of 11Be, our calculation well reproduces the experimental results, but for negative parity states, not so well. With reducing the coupling between the core deformation and a valence neutron, the negative parity levels of the 11Be nucleus are much improved.
{"title":"Low-Energy Spectrum of One-Neutron Halo Nucleus 11 Be","authors":"R. Suzuki, T. Myo, K. Katō, K. Ikeda","doi":"10.1556/APH.13.2001.1-3.21","DOIUrl":"https://doi.org/10.1556/APH.13.2001.1-3.21","url":null,"abstract":"We investigate the low-energy spectrum of the one-neutron halo nucleus 11Be using the complex scaled coupled channel method for a 10Be + n model, paying attention to the effects of the deformation of the 10Be-core and the Pauli principle between the core and a valence neutron. For positive parity states of 11Be, our calculation well reproduces the experimental results, but for negative parity states, not so well. With reducing the coupling between the core deformation and a valence neutron, the negative parity levels of the 11Be nucleus are much improved.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"6 1","pages":"169-173"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76143267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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