The chiral doublet bands with three-quasiparticle configuration (πg9/2)-1 (vh11/2)2 are studied by the fully quantal triaxial particle rotor model. The energy spectra and B(M1)/B(E2) ratios of the doublet ban...The chiral doublet bands with three-quasiparticle configuration (πg9/2)-1 (vh11/2)2 are studied by the fully quantal triaxial particle rotor model. The energy spectra and B(M1)/B(E2) ratios of the doublet bands with different triaxiality parameter γ are systematically analyzed. It is found that γ is a sensitive parameter for the properties of these doublet bands.展开更多
Properties of the chair doublet bands of the odd-odd Cs isotopes built on the πh11/2× vh11/2 configuration are investigated systematically within the supersymmetry scheme including many-body interactions and pos...Properties of the chair doublet bands of the odd-odd Cs isotopes built on the πh11/2× vh11/2 configuration are investigated systematically within the supersymmetry scheme including many-body interactions and possessing the SO(5)(or SU(5)) symmetry on the rotational symmetry. Quantitatively good results of the energy spectra, the energy staggering parameter as a function of the spin are obtained. The calculation shows that the stronger competition between the pairing and anti-pairing effects and the SU(3) symmetry broking more seriously exist in the stable chiral structure.展开更多
A critical point symmetry(CPS) for odd-odd nuclei is built in the core-particle coupling scheme with the even-even core assumed to follow the spherical to triaxially deformed shape phase transition. It is shown that t...A critical point symmetry(CPS) for odd-odd nuclei is built in the core-particle coupling scheme with the even-even core assumed to follow the spherical to triaxially deformed shape phase transition. It is shown that the model Hamiltonian can be approximately solved with the solutions being expressed in terms of the Bessel functions of irrational orders. In particular, the CPS predicts that collective multiple chiral doublets may exist in transitional odd-odd systems.展开更多
Recent progress regarding multiple chiral doublet bands(MχD)is reviewed from the experimental and theoretical perspectives.In particular,the experimental findings,theoretical predictions,selection rule for electromag...Recent progress regarding multiple chiral doublet bands(MχD)is reviewed from the experimental and theoretical perspectives.In particular,the experimental findings,theoretical predictions,selection rule for electromagnetic transitions,MχD with octupole correlations,and some related topics are highlighted.Based on these discussions,it is of great scientific interest to search for the other MχD,as well as possible chiral wobblers,chirality-parity quartet bands,and chirality-pseudospin triplet(or quartet)bands in the nuclear system.展开更多
Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the e...Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.展开更多
Multiple chiral doublet bands (MχD) in the 80, 130 and 190 mass regions are studied by the model of γ=90°triaxial rotor coupled with identical symmetric proton-neutron configurations. By selecting a suitable ...Multiple chiral doublet bands (MχD) in the 80, 130 and 190 mass regions are studied by the model of γ=90°triaxial rotor coupled with identical symmetric proton-neutron configurations. By selecting a suitable basis, the calculated wave functions are explicitly exhibited to be symmetric under the operator A, which is defined as rotation by 90° about the 3-axis with the exchange of valance proton and neutron. We found that both M1 and E2 transitions are allowed between levels with different values of A, while they are forbidden between levels with same values of A. Such a selection rule holds true for MχD in different mass regions.展开更多
The candidate chiral doublet bands in 98 Tc with configuration πg9/2νh11/2 are studied the- oretically for the first time via the triaxial particle rotor model. The main properties of the doublet bands including the...The candidate chiral doublet bands in 98 Tc with configuration πg9/2νh11/2 are studied the- oretically for the first time via the triaxial particle rotor model. The main properties of the doublet bands including the energy spectra and electromagnetic transitions are calculated for different triaxiality parameter γ, and the data in 98Tc can be well described by the calculations with γ = 38°. Based on the analysis of angular momentum components, it is found that the chiral rotational geometry in 98Tc deviates from the ideal chiral picture.展开更多
The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with πh11/2×γh11/2^-1.The energy spect...The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with πh11/2×γh11/2^-1.The energy spectra,electromagnetic transition probabilities B(M1) and B(E2),angular momenta,and K-distributions are studied.It is demonstrated that the chirality still remains not only in the yrast and yrare bands,but also in the two higher excited bands whenγ deviates from 30°.The chiral geometry relies significantly on γ,and the chiral geometry of the two higher excited partner bands is not as good as that of the yrast and yrare doublet bands.展开更多
The level structures of neutron-rich 105Mo,106Mo,108Mo and 110Ru nuclei in A ≈ 100 region have been carefully investigated by coincidence measurements of the prompt γ-rays populated in the spontaneous fission of 252...The level structures of neutron-rich 105Mo,106Mo,108Mo and 110Ru nuclei in A ≈ 100 region have been carefully investigated by coincidence measurements of the prompt γ-rays populated in the spontaneous fission of 252Cf with the Gammasphere detector array. In 105Mo,one-phonon K=9/2 and two-phonon K=13/2 γ-vibrational bands have been identified. In 108Mo,one-phonon γ-vibrational band is expanded and two-phonon γ-vibrational band has been identified. Two similar sets of bands in 106Mo and 110Ru are observed to high spins,which have been proposed as the soft chiral γ-vibrational bands. The characteristics for these γ-vibrational bands and chiral doublet bands have been discussed.展开更多
Positive-parity doublet bands were reported in 120I.Based on these,we discuss the corresponding experimental characteristics,including rotational alignment,and re-examine the corresponding configuration assignment.The...Positive-parity doublet bands were reported in 120I.Based on these,we discuss the corresponding experimental characteristics,including rotational alignment,and re-examine the corresponding configuration assignment.The self-consistent tilted axis cranking relativistic mean-field calculations indicate that the doublet bands are built on the configurationπh11/2νh11/2^-1.By adopting the two quasiparticles coupled with a triaxial rotor model,the excitation energies,energy staggering parameter S(I),B(M1)/B(E2),effective angles,and K plots are discussed and compared with available data.The obtained results support the interpretation of chiral doublet bands for the positive-parity doublet bands in 120I,and hence identify this nucleus as the border of the A≈130 island of chiral candidates.展开更多
High spin states in A~110 neutron-rich 106Mo, 110Ru and 112Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of 252Cf. Two similar sets of bands are observed to high spin...High spin states in A~110 neutron-rich 106Mo, 110Ru and 112Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of 252Cf. Two similar sets of bands are observed to high spins in each of three nuclei. Through analyzing of characters of the band structures, the chiral doublet bands are suggested in 106Mo, 110Ru and 112Ru.展开更多
The potential energy surfaces of the even-even 68-92Se, 112-150Ba, and 208-230Ra isotopes are calculated using the macroscopic-microscopic method in a multidimensional space {αλ,μ} including quadrupole (λ=2, μ=0...The potential energy surfaces of the even-even 68-92Se, 112-150Ba, and 208-230Ra isotopes are calculated using the macroscopic-microscopic method in a multidimensional space {αλ,μ} including quadrupole (λ=2, μ=0, 2) and octupole (λ=3, μ=0, 1, 2, 3) degrees of freedom. The calculated results show that the even-even isotopes 92Se, 112,114,144-150Ba and 220-228Ra can exhibit the coexistence of triaxial and octupole deformations, thereby leading to simultaneous chiral and reflected symmetry breaking. Therefore, chirality-parity quartet bands are expected in these and their neighboring odd-A/odd-odd nuclei.展开更多
Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2/1/2νh11/2 doublet bands in the A~100 mass region are studied, and compared with the πg9/2/1/2νh11/2 doublet bands. It is fou...Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2/1/2νh11/2 doublet bands in the A~100 mass region are studied, and compared with the πg9/2/1/2νh11/2 doublet bands. It is found that the calculated results for the configuration of πg9/2/1/2νh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn = ε5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.展开更多
Following the observation of candidate chiral doublet bands in ^(78,80)Br, triaxial deformations with corresponding configurations in odd-odd bromine isotopes have been investigated using adiabatic and configuration-f...Following the observation of candidate chiral doublet bands in ^(78,80)Br, triaxial deformations with corresponding configurations in odd-odd bromine isotopes have been investigated using adiabatic and configuration-fixed constrained triaxial relativistic-meanfield calculations with an aim of finding the boundary of chirality in the chain of Br isotopes. Several minima with triaxial deformation and the proper particle-hole configuration were obtained in ^(74,76,78,80,82)Br, where the chiral doublet bands have the possibility of occurrence. Furthermore, the possible existence of multiple chiral doublet(MχD) bands is demonstrated in ^(74,76,78,80,82)Br.Experiments to explore the chirality and MχD properties of Br isotopes are conducted to verify the predictions.展开更多
基金supported by National Natural Science Foundation of China(Nos.11005069,10875074,11175108)
文摘The chiral doublet bands with three-quasiparticle configuration (πg9/2)-1 (vh11/2)2 are studied by the fully quantal triaxial particle rotor model. The energy spectra and B(M1)/B(E2) ratios of the doublet bands with different triaxiality parameter γ are systematically analyzed. It is found that γ is a sensitive parameter for the properties of these doublet bands.
基金Supported by the National Natural Science Foundation of China under Grant No.10475026the Natural Science Foundation of Zhejiang Province under Grant No.KY607518
文摘Properties of the chair doublet bands of the odd-odd Cs isotopes built on the πh11/2× vh11/2 configuration are investigated systematically within the supersymmetry scheme including many-body interactions and possessing the SO(5)(or SU(5)) symmetry on the rotational symmetry. Quantitatively good results of the energy spectra, the energy staggering parameter as a function of the spin are obtained. The calculation shows that the stronger competition between the pairing and anti-pairing effects and the SU(3) symmetry broking more seriously exist in the stable chiral structure.
基金supported by the National Natural Science Foundation of China(Grant Nos.11875158,11675094,and 11875075)。
文摘A critical point symmetry(CPS) for odd-odd nuclei is built in the core-particle coupling scheme with the even-even core assumed to follow the spherical to triaxially deformed shape phase transition. It is shown that the model Hamiltonian can be approximately solved with the solutions being expressed in terms of the Bessel functions of irrational orders. In particular, the CPS predicts that collective multiple chiral doublets may exist in transitional odd-odd systems.
基金Supported by the Shandong Natural Science Foundation,China(JQ201701)the National Natural Science Foundation of China(11622540)。
文摘Recent progress regarding multiple chiral doublet bands(MχD)is reviewed from the experimental and theoretical perspectives.In particular,the experimental findings,theoretical predictions,selection rule for electromagnetic transitions,MχD with octupole correlations,and some related topics are highlighted.Based on these discussions,it is of great scientific interest to search for the other MχD,as well as possible chiral wobblers,chirality-parity quartet bands,and chirality-pseudospin triplet(or quartet)bands in the nuclear system.
基金Supported by National Natural Science Foundation of China (10505002, 10435010, 10605001, 10221003)Postdoctoral Science Foundation of China (20060390371)
文摘Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.
基金Supported by National Natural Science Foundation of China(11675094,11622540,11545011,11405096,11461141001,U1432119)Shandong Natural Science Foundation(ZR2014AQ012)Young Scholars Program of Shandong University,Weihai(2015WHWLJH01)
文摘Multiple chiral doublet bands (MχD) in the 80, 130 and 190 mass regions are studied by the model of γ=90°triaxial rotor coupled with identical symmetric proton-neutron configurations. By selecting a suitable basis, the calculated wave functions are explicitly exhibited to be symmetric under the operator A, which is defined as rotation by 90° about the 3-axis with the exchange of valance proton and neutron. We found that both M1 and E2 transitions are allowed between levels with different values of A, while they are forbidden between levels with same values of A. Such a selection rule holds true for MχD in different mass regions.
基金Supported by National Natural Science Foundation of China (11005069, 11175108)Shandong Natural Science Foundation (ZR2010AQ005)
文摘The candidate chiral doublet bands in 98 Tc with configuration πg9/2νh11/2 are studied the- oretically for the first time via the triaxial particle rotor model. The main properties of the doublet bands including the energy spectra and electromagnetic transitions are calculated for different triaxiality parameter γ, and the data in 98Tc can be well described by the calculations with γ = 38°. Based on the analysis of angular momentum components, it is found that the chiral rotational geometry in 98Tc deviates from the ideal chiral picture.
基金Supported by Plan Project of Beijing College Students' Scientific Research and Entrepreneurial Action,Major State 973 Program of China(2013CB834400)National Natural Science Foundation of China(11175002,11335002,11375015,11461141002)+2 种基金National Fund for Fostering Talents of Basic Science(NFFTBS)(J1103206)Research Fund for Doctoral Program of Higher Education(20110001110087)China Postdoctoral Science Foundation(2015M580007)
文摘The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with πh11/2×γh11/2^-1.The energy spectra,electromagnetic transition probabilities B(M1) and B(E2),angular momenta,and K-distributions are studied.It is demonstrated that the chirality still remains not only in the yrast and yrare bands,but also in the two higher excited bands whenγ deviates from 30°.The chiral geometry relies significantly on γ,and the chiral geometry of the two higher excited partner bands is not as good as that of the yrast and yrare doublet bands.
基金National Natural Science Foundation of China(10575057,10775078)Major State Basic Research Development Program of China(2007CB815005)+1 种基金Special Program of Higher Education Science Foundation of China(20070003149)U.S. Department of Energy(DE-FG05-88ER40407,and DE-AC03-76SF00098)
文摘The level structures of neutron-rich 105Mo,106Mo,108Mo and 110Ru nuclei in A ≈ 100 region have been carefully investigated by coincidence measurements of the prompt γ-rays populated in the spontaneous fission of 252Cf with the Gammasphere detector array. In 105Mo,one-phonon K=9/2 and two-phonon K=13/2 γ-vibrational bands have been identified. In 108Mo,one-phonon γ-vibrational band is expanded and two-phonon γ-vibrational band has been identified. Two similar sets of bands in 106Mo and 110Ru are observed to high spins,which have been proposed as the soft chiral γ-vibrational bands. The characteristics for these γ-vibrational bands and chiral doublet bands have been discussed.
基金Supported by the National Natural Science Foundation of China(11675063,11205068,11475072,11847310)。
文摘Positive-parity doublet bands were reported in 120I.Based on these,we discuss the corresponding experimental characteristics,including rotational alignment,and re-examine the corresponding configuration assignment.The self-consistent tilted axis cranking relativistic mean-field calculations indicate that the doublet bands are built on the configurationπh11/2νh11/2^-1.By adopting the two quasiparticles coupled with a triaxial rotor model,the excitation energies,energy staggering parameter S(I),B(M1)/B(E2),effective angles,and K plots are discussed and compared with available data.The obtained results support the interpretation of chiral doublet bands for the positive-parity doublet bands in 120I,and hence identify this nucleus as the border of the A≈130 island of chiral candidates.
基金Supported by National Natural Science Foundation of China (10575057, 10775078)Major State Basic Research Development Program (2007CB815005)+1 种基金Special Program of Higher Education Science Foundation (20070003149)U.S. Department of Energy (DE-FG05-88ER40407, DE-AC03-76SF00098)
文摘High spin states in A~110 neutron-rich 106Mo, 110Ru and 112Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of 252Cf. Two similar sets of bands are observed to high spins in each of three nuclei. Through analyzing of characters of the band structures, the chiral doublet bands are suggested in 106Mo, 110Ru and 112Ru.
基金Supported by Natural Science Foundation of China(11705102,11622540,11675094)the Shandong Natural Science Foundation(ZR2017PA005,JQ201701)+1 种基金the China Postdoctoral Science Foundation(2017M612254)the Young Scholars Program of Shandong University,Weihai(2015WHWLJH01)
文摘The potential energy surfaces of the even-even 68-92Se, 112-150Ba, and 208-230Ra isotopes are calculated using the macroscopic-microscopic method in a multidimensional space {αλ,μ} including quadrupole (λ=2, μ=0, 2) and octupole (λ=3, μ=0, 1, 2, 3) degrees of freedom. The calculated results show that the even-even isotopes 92Se, 112,114,144-150Ba and 220-228Ra can exhibit the coexistence of triaxial and octupole deformations, thereby leading to simultaneous chiral and reflected symmetry breaking. Therefore, chirality-parity quartet bands are expected in these and their neighboring odd-A/odd-odd nuclei.
基金Supported by National Natural Science Foundation of China (10875074, 10605001, 10435010, 10221003, 10505002)
文摘Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2/1/2νh11/2 doublet bands in the A~100 mass region are studied, and compared with the πg9/2/1/2νh11/2 doublet bands. It is found that the calculated results for the configuration of πg9/2/1/2νh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn = ε5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.
基金supported by the National Natural Science Foundation of China(Grant Nos.11675094,11622540,and 11705102)the Young Scholars Program of Shandong University,Weihai of China(Grant No.2015WHWLJH01)the Shandong Natural Science Foundation,China(Grant No.JQ201701)
文摘Following the observation of candidate chiral doublet bands in ^(78,80)Br, triaxial deformations with corresponding configurations in odd-odd bromine isotopes have been investigated using adiabatic and configuration-fixed constrained triaxial relativistic-meanfield calculations with an aim of finding the boundary of chirality in the chain of Br isotopes. Several minima with triaxial deformation and the proper particle-hole configuration were obtained in ^(74,76,78,80,82)Br, where the chiral doublet bands have the possibility of occurrence. Furthermore, the possible existence of multiple chiral doublet(MχD) bands is demonstrated in ^(74,76,78,80,82)Br.Experiments to explore the chirality and MχD properties of Br isotopes are conducted to verify the predictions.