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811.
报道了在新建成的放射性次级束流线上完成的20Na的β+缓发α粒子发射20Na—→β+ 20Ne→16O+α的在束测量.通过飞行时间和能损符合的方法实现20Na次级束流的在束鉴别与调制.在束和停束两个获取时段分别完成对次级束流和β+缓发粒子的记录.利用脉冲发生器和记数器实现20Na缓发粒子衰变半衰期的测量.实验测量到20Ne几个低能共振能级的衰变能量分别为2.69,3.09,4.74,5.54MeV,相对强度分别为100,4.15,1.10,15.20.测量到20Na的β+缓发α衰变的半衰期为(459±7)ms,与现有的核数据基本上吻合. 相似文献
812.
16O(α,γ)20Ne反应的实验研究 总被引:1,自引:0,他引:1
讨论了目前16O(α ,γ) 2 0 Ne反应的实验研究工作 ,并对2 0 Na β+—→2 0 N →16O +α的β+ 缓发衰变α能谱的相对强度值同文献进行了比较 ,讨论了低能激发能级、共振强度及其对共振截面的贡献、S因子的理论研究.The experimental investigations of 16 O(α,γ) 20 Ne reaction is reviewed. The energy spectrum of β + delay α decay were measured through the 20 Naβ +-→ 20 Ne *→ 16 O+α process, and the relative densities of α decays are compared with the reference s results. The low excitation energy levels, resonance strength and its contribution to the resonance crosses section are also discussed. Finally, we have calculated the reaction rate of the direct capture reaction....... 相似文献
813.
XINGLi-Rong MAWen-Gain ZHANGRen-You SUNYah-Bin HOUHong-Sheng 《理论物理通讯》2003,40(2):171-182
We investigate the effects from complex parameters on the branching ratio (BR) of the flavor changing rare decay t→ch^0 contributed by the electroweak interactions in the framework of the minimal supersymmetric standard model with complex parameters. We study the dependence of the BR on the possible relevant additional parameter swhich could be the originalsources inducing CP-violation, i.e., the complex phase angles φμ and φAb in squark and chargino sectors and δ13 appearing in Cabibbo-Kobayashi-Maskawa matrix. We find that these parameters influence the BR obviously and the effects induced by φμ and φAb are much larger than by δ13. With the different chosen values of the complex parameters, the BR is in the range between 10^-10 and 10^-8, depending mainly on the phase angles of the higgsino mass parameter μ and the trilinear coupling Ab. 相似文献
814.
The lepton flavor violating process μ - eγ has been previously studied in a model of electroweak-scale right-handed neutrinos. In that work the decay amplitude was computed in unitarity gauge, augmented by some technical considerations that correct the leading term thus obtained. This complication arises because the mixing matrices appearing in the weak charged currents are not unitary in the model. In this paper, we recalculate the amplitude in Re gauge. The cancellation of the ξ dependence in the final result serves as a useful check to both the obtained amplitude and the technical points made in the previous work. 相似文献
815.
816.
ZHANG Jie LIU Men-Quan LUO Zhi-Quan 《理论物理通讯》2007,47(4):765-768
Based on shell model of nuclei, the influence of a high magnetic field on β^+ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^+ decay but a strong magnetic field (B 〉 10^11 G) improves β^+ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future. 相似文献
817.
Radiative decay from doubly to singly excited states of He via generalization of Laguerre-type orbitals: A non-orthogonal formalism
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By taking full account of the non-orthogonality of the orbitals
between the low-lying doubly excited states 1Po and the
singly excited states 1Se and 12De of He, the
corresponding radiative decay rates have been investigated
theoretically via analytic generalized Laguerre-type atomic orbitals
at a nearly numerical multi-configuration self-consistent field
accuracy in a general non-orthogonal configuration interaction
scheme. From these rates, we calculate the VUV photon emission and
metastable atom spectra, and both are found to be in good qualitative
agreement with recent excellent measurements. We obtain,
successfully, the enhancement of the VUV photon spectrum,
experimentally observed at the energy of (2s4p-4s2p)/(2p,3d)
1Po as compared with other nearby lying states. The
mechanism proposed by Odling-Smee et al is verified, implying
that taking appropriate account of the overlap existing between
orbitals of the low-lying doubly excited and singly excited states
(especially important for the compact orbitals) can reveal basic
physical dominant mechanism and is crucial in understanding these
spectra. 相似文献
818.
ZHANG Li-Hua XUE Zheng-Yuan YANG Ming CAO Zhuo-Liang 《理论物理通讯》2006,46(4):610-612
We present a physical scheme to teleport an unknown atomic entangled state via cavity decay. In the teleportation process, four-particle Greenberger-Horne-Zeilinger (GHZ) state is used as quantum channel, and two unknown entangled atoms and two of four atoms in the four-particle GHZ state are trapped in four leaky cavities, respectively. Based on the joint detection of the photons leak out from the four cavities, we can teleport an unknown entangled state to two other remote atoms with certain probability and high fidelity. 相似文献
819.
ITER 试验包层模块活化计算与环境安全分析 总被引:1,自引:1,他引:0
运用聚变堆放射性计算程序FDKR 和衰变链数据库AFDC-DLIB, 计算了ITER 中国氦冷固态增殖试验包层模块设计中活化产物的放射性、衰变余热和潜在生物危害因子BHP 值。计算结果表明: 对于试验包层模块来说, 在500MW 聚变功率下运行一年, 停堆时的总放射性、余热和BHP 值分别为2. 10× 1016Bq 、5. 06 × 10- 3MW 和 68. 6km3•( kW) - 1。结果表明: 中国氦冷实验包层模块不存在突出的安全问题。 相似文献
820.
PANG Cai-Ying PING Rong-Gang 《理论物理通讯》2009,51(6):1091-1094
The helicity amplitudes for the processes of e^+e^- →J/ψ→γηc→γYY(Y: hyperon) are presented, together with the joint angular distributions for ηc decays into ∧∧,∑^0 ∑^0, and [1]-[1]+. The sensitivities to measure the hyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bell inequality in experiment using the decay of ηc→∧∧ are discussed. 相似文献