分类： 核科学技术 >> 核科学与技术 提交时间： 2025-06-30
摘要： Exploring the limits of neutron binding in atomic nuclei remains a central focus of nuclear physics. However, the experimental determination of the neutron drip line is challenging because of the minuscule production cross sections of the most neutron-rich isotopes. We investigated the effectiveness of multi-step fragmentation for producing extremely neutron-rich nuclides at relativistic energies. We demonstrate that multi-step fragmentation dominates over single-step fragmentation in thick target experiments and can enhance the yields of drip line nuclei by several orders of magnitude in a realistic experiment using fragment separators. Such enhancements open new possibilities for locating drip lines above sodium, and thus significantly expand the research horizon.
分类： 物理学 >> 核物理学 提交时间： 2023-07-03
摘要： Following the reports of candidate chiral doublet bands observed in cesium isotopes, the possible chiral candidates and the evolution of three-dimensional rotation in $^{120-134}{ textrm{Cs}}$ are investigated within the microscopic three-dimensional tilted axis cranking covariant density functional theory (3DTAC-CDFT). By investigating the evolution of the polar angle $ theta$ and azimuth angle $ varphi$ as a function of rotational frequency $ hbar omega$, the transition from the planar rotation to the chiral rotation has been found in $^{121-133}{ textrm{Cs}}$. The corresponding critical rotational frequency $ omega_{ textrm{crit}}$ of the appearance of chiral aplanar rotation decreases as neutron number increases, which can be attributed to the neutrons in $(gd)$ and $(sd)$ shells having smaller angular momentum components along both the short and long axes, and larger components along medium axis, respectively. In comparison, only planar rotation has been obtained in $^{120,134}{ textrm{Cs}}$. With these interpretations, the obtained $I sim hbar omega$ and energy spectra as well as $B(M1)/B(E2)$ values show reasonable agreement with the available experimental data. In addition, the evolution of quadrupole deformation $ beta$ and triaxial deformation $ gamma$ are also discussed.
分类： 物理学 >> 核物理学 提交时间： 2016-09-13
摘要： A high luminosity Circular Electron Positron Collider (CEPC) as a Higgs Factory will be helpful to the precision measurement of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in the associated Z boson production at the future e+e− colliders at energy 246GeV. The mass shifts go up from about 20MeV to 50MeV for the experimental mass resolution ranging from 0.8GeV to 2GeV.
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