High-energy nuclear collisions encompass three key stages:the structure of the colliding nuclei,informed by low-energy nuclear physics,the initial condition,leading to the formation of quark-gluon plasma(QGP),and the ...High-energy nuclear collisions encompass three key stages:the structure of the colliding nuclei,informed by low-energy nuclear physics,the initial condition,leading to the formation of quark-gluon plasma(QGP),and the hydrodynamic expansion and hadronization of the QGP,leading to fnal-state hadron distributions that are observed experimentally.Recent advances in both experimental and theoretical methods have ushered in a precision era of heavy-ion collisions,enabling an increasingly accurate understanding of these stages.However,most approaches involve simultaneously determining both QGP properties and initial conditions from a single collision system,creating complexity due to the coupled contributions of these stages to the fnal-state observables.To avoid this,we propose leveraging established knowledge of low-energy nuclear structures and hydrodynamic observables to independently constrain the QGP's initial condition.By conducting comparative studies of collisions involving isobar-like nuclei—species with similar mass numbers but diferent ground-state geometries—we can disentangle the initial condition's impacts from the QGP properties.This approach not only refnes our understanding of the initial stages of the collisions but also turns high-energy nuclear experiments into a precision tool for imaging nuclear structures,ofering insights that complement traditional low-energy approaches.Opportunities for carrying out such comparative experiments at the Large Hadron Collider and other facilities could signifcantly advance both highenergy and low-energy nuclear physics.Additionally,this approach has implications for the future electron-ion collider.While the possibilities are extensive,we focus on selected proposals that could beneft both the high-energy and low-energy nuclear physics communities.Originally prepared as input for the long-range plan of U.S.nuclear physics,this white paper refects the status as of September 2022,with a brief update on developments since then.展开更多
To compare with the predictions of the transitional dynamical symmetry X（5） proposed by Iachello （2001 Phys. Rev. Lett. 87 052502）, the critical behaviours of U（5） SU（3） are studied in the space of two control...To compare with the predictions of the transitional dynamical symmetry X（5） proposed by Iachello （2001 Phys. Rev. Lett. 87 052502）, the critical behaviours of U（5） SU（3） are studied in the space of two control parameters in the interacting boson model （IBM）. A simple-shaped phased diagram has been presented. It is found that X（5） predictions cannot be exactly reproduced by our calculations and that the best agreement is close to the calculations with boson numbers N = 11 and 12. By comparing with experimental data on X（5）-like nuclei, we find that X（5） predictions and IBM calculations can reproduce the energy ratios and E2 transition ones.展开更多
The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear ...The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ rays of 0.25-21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 21.7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experiments in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and Light-Charged Particle(LCP) spectrometry methods have been developed.展开更多
A novel technique of isochronous mass spectrometry(IMS),termed Bρ-defned IMS,was developed at the experimental cooler-storage ring CSRe in Lanzhou for the frst time.Two time-of-fight detectors were installed in a str...A novel technique of isochronous mass spectrometry(IMS),termed Bρ-defned IMS,was developed at the experimental cooler-storage ring CSRe in Lanzhou for the frst time.Two time-of-fight detectors were installed in a straight section of the CSRe,thereby enabling simultaneous measurements of the velocity and revolution time of each stored short-lived ion.This technique boosts the broadband precision,efciency,sensitivity,and accuracy of mass measurements of short-lived exotic nuclides.Using Bρ-defned IMS,the masses of^(22)Al,^(62)Ge,^(64)As,^(66)Se,and^(70)Kr were measured for the frst time,and the masses of^(65)As,^(67)Se,and other 21 nuclides were redetermined with improved accuracy.Mass data have been used in studies of relevant issues regarding nuclear structures and nuclear astrophysics.Herein,we review the development of experimental techniques and main physical results and outline plans for future experiments.展开更多
The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te（19F, 4n） reaction at a beam energy of 90 MeV. The previous level scheme has been extended with...The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te（19F, 4n） reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 h. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong AI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ--60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ--90°. The characteristics for these bands have been discussed.展开更多
An angular momentum projected potential-energy-surface （PES） calculation, which takes both rotational symmetry restoration and multi-quasiparticle excitation into account, is developed by using the macroscopic-micro...An angular momentum projected potential-energy-surface （PES） calculation, which takes both rotational symmetry restoration and multi-quasiparticle excitation into account, is developed by using the macroscopic-microscopic model and the projected shell model （PSM）. Within this method, it may become possible to modify the excitation spectra which are influenced by shape-softness of nuclei, including high-K states. As our first example, this method is adopted to study the collective and multi-quasiparticle excitations of 178Hf~ and the results are in good agreement with the existing experimental data. In addition, as for the dominant structure of non- collective 6＋ bands, the conflict between experimental result and the previous PSM calculation is clarified.展开更多
Molecular dynamics simulations are performed with the recently developed empirical interaction potential by Morelon et al. Thermodynamics properties of solid UO2 that have been assessed include melt point, density, en...Molecular dynamics simulations are performed with the recently developed empirical interaction potential by Morelon et al. Thermodynamics properties of solid UO2 that have been assessed include melt point, density, enthalpy, heat capacity, lattice parameter variation with temperature, mean-square-displacement and diffusion coefficients of oxygen ion. The results are compared with the data in literature and it is suggested that the rigid ionic potential provides perfect results below the superionic range. The data showing thermodynamics properties will become unacceptable when the temperature is higher than 2500 K. Compared with the previous empirical potentials, the empirical potential developed by Morelon et al. improves the agreement of these data with the recommend ones.展开更多
基金U.S.Department of Energy,Office of Science,Ofifce of Nuclear Physics,under Award or Contract No.DE-SC002418(JDB),DE-SC0024602(SH,JJ,CZ),DE-SC0004286(UH),DE-FG02-10ER41666(CL,WL),DE-SC0013365,DE-SC0024586 and DE-SC0023175(DL),DE-SC0011088(YL),DE-AC02-05CH11231(MP),DE-FG02-89ER40531(AT),DE-SC0012704(BS),DE-SC0021969 and DE-SC0024232(CS),DE-SC0023861(JN),DE-FG02-07ER41521(ZX)by National Science Foundation under grant number OAC-2103680(JN)+1 种基金by European Union(ERC,Initial Conditions),VILLUM FONDEN with grant no.00025462,and Danmarks Frie Forskningsfond(YZ)by FAPESP projects 2017/05685-2,2018/24720-6,and 2021/08465-9,project INCT-FNA Proc.~No.~464898/2014-5,and CAPES-Finance Code 001(ML)。
文摘High-energy nuclear collisions encompass three key stages:the structure of the colliding nuclei,informed by low-energy nuclear physics,the initial condition,leading to the formation of quark-gluon plasma(QGP),and the hydrodynamic expansion and hadronization of the QGP,leading to fnal-state hadron distributions that are observed experimentally.Recent advances in both experimental and theoretical methods have ushered in a precision era of heavy-ion collisions,enabling an increasingly accurate understanding of these stages.However,most approaches involve simultaneously determining both QGP properties and initial conditions from a single collision system,creating complexity due to the coupled contributions of these stages to the fnal-state observables.To avoid this,we propose leveraging established knowledge of low-energy nuclear structures and hydrodynamic observables to independently constrain the QGP's initial condition.By conducting comparative studies of collisions involving isobar-like nuclei—species with similar mass numbers but diferent ground-state geometries—we can disentangle the initial condition's impacts from the QGP properties.This approach not only refnes our understanding of the initial stages of the collisions but also turns high-energy nuclear experiments into a precision tool for imaging nuclear structures,ofering insights that complement traditional low-energy approaches.Opportunities for carrying out such comparative experiments at the Large Hadron Collider and other facilities could signifcantly advance both highenergy and low-energy nuclear physics.Additionally,this approach has implications for the future electron-ion collider.While the possibilities are extensive,we focus on selected proposals that could beneft both the high-energy and low-energy nuclear physics communities.Originally prepared as input for the long-range plan of U.S.nuclear physics,this white paper refects the status as of September 2022,with a brief update on developments since then.
基金Project supported in part by the National Natural Science Foundation of China （Grant Nos 10265001 and 10547003）, the Natural Science Foundation of Inner Mongolian, China （Grant No 200607010111）, and Chifeng College Scientific Research Fund of China （Grant No ZRZD200604）. Acknowledgement The authors are greatly indebted to Professor Long G L for his continuing interest in this work and his many suggestions.
文摘To compare with the predictions of the transitional dynamical symmetry X（5） proposed by Iachello （2001 Phys. Rev. Lett. 87 052502）, the critical behaviours of U（5） SU（3） are studied in the space of two control parameters in the interacting boson model （IBM）. A simple-shaped phased diagram has been presented. It is found that X（5） predictions cannot be exactly reproduced by our calculations and that the best agreement is close to the calculations with boson numbers N = 11 and 12. By comparing with experimental data on X（5）-like nuclei, we find that X（5） predictions and IBM calculations can reproduce the energy ratios and E2 transition ones.
文摘The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ rays of 0.25-21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 21.7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experiments in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and Light-Charged Particle(LCP) spectrometry methods have been developed.
基金National Key R&D Program of China(Grant No.2023YFA1606401)CAS Project for Young Scientists in Basic Research(Grant No.YSBR-002)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB34000000)NSFC(Grant No.12305126)。
文摘A novel technique of isochronous mass spectrometry(IMS),termed Bρ-defned IMS,was developed at the experimental cooler-storage ring CSRe in Lanzhou for the frst time.Two time-of-fight detectors were installed in a straight section of the CSRe,thereby enabling simultaneous measurements of the velocity and revolution time of each stored short-lived ion.This technique boosts the broadband precision,efciency,sensitivity,and accuracy of mass measurements of short-lived exotic nuclides.Using Bρ-defned IMS,the masses of^(22)Al,^(62)Ge,^(64)As,^(66)Se,and^(70)Kr were measured for the frst time,and the masses of^(65)As,^(67)Se,and other 21 nuclides were redetermined with improved accuracy.Mass data have been used in studies of relevant issues regarding nuclear structures and nuclear astrophysics.Herein,we review the development of experimental techniques and main physical results and outline plans for future experiments.
基金supported by National Natural Science Foundation of China (Nos. 10975082, 10775078)the Major State Basic Research Development Program of China (No. 2007CB815005)the Special Program of Higher Education Science Foundation of China (No. 20070003149)
文摘The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te（19F, 4n） reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 h. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong AI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ--60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ--90°. The characteristics for these bands have been discussed.
基金supported by Natural Science Foundation of China (Nos. 10735010, 10975006)the Chinese Major State Basic Research Development Program (No. 2007CB815000)
文摘An angular momentum projected potential-energy-surface （PES） calculation, which takes both rotational symmetry restoration and multi-quasiparticle excitation into account, is developed by using the macroscopic-microscopic model and the projected shell model （PSM）. Within this method, it may become possible to modify the excitation spectra which are influenced by shape-softness of nuclei, including high-K states. As our first example, this method is adopted to study the collective and multi-quasiparticle excitations of 178Hf~ and the results are in good agreement with the existing experimental data. In addition, as for the dominant structure of non- collective 6＋ bands, the conflict between experimental result and the previous PSM calculation is clarified.
文摘Molecular dynamics simulations are performed with the recently developed empirical interaction potential by Morelon et al. Thermodynamics properties of solid UO2 that have been assessed include melt point, density, enthalpy, heat capacity, lattice parameter variation with temperature, mean-square-displacement and diffusion coefficients of oxygen ion. The results are compared with the data in literature and it is suggested that the rigid ionic potential provides perfect results below the superionic range. The data showing thermodynamics properties will become unacceptable when the temperature is higher than 2500 K. Compared with the previous empirical potentials, the empirical potential developed by Morelon et al. improves the agreement of these data with the recommend ones.
