共查询到20条相似文献,搜索用时 218 毫秒
1.
133Sm was produced via fusion evaporation in the reaction 40Ca+96Ru. Its β-delayed proton decay was studied by means of “p-γ” coincidence in combination with a He-jet tape transport system, including half-lives, proton energy spectra, γ-transitions following the proton emissions, and the branching ratios to the low-lying states in the grand-daughter nuclei. The possible spins and parities of 133Sm were extracted by fitting the experimental data with a statistical model calculation. The configuration-constrained nuclear potential energy surfaces of 133Sm were calculated by using the Woods-Saxon Strutinsky method. Comparing the experimental and calculated results, the spins and parities of 133Sm were assigned to be 5/2+ and 1/2-, which is reconciled with our published simple (EC+β+) decay scheme of 133Sm in 2001. In addition, our experimental data on the beta-delayed proton decay of 149Yb reported in Eur. Phys. J., 2001, A12: 1—4 was also analyzed by using the same method. The spin and parity of 149Yb was assigned to be 1/2-. 相似文献
2.
XIE YuanXiang XU ShuWei Li ZhanKui YU Yong PAN QiangYan WANG ChunFang ZHANG TianMei LONG GuiLu LI YanSong 《中国物理C(英文版)》2000,24(8):719-724
130Pm and 128 Pr were produced by irradiation of 96Ru with 171MeV 36Ar beam,and a He-jet recoil tape transport system transported radioactivities to shielded reigon. Based on X-γ-t and γ-γ-t coincidence measurements ,the (EC+β+)decay scheme of 130Pm was proposed for the first time and the (EC+β+)decay scheme of 128Pr was revised. 相似文献
3.
WANG Hong-Wei WU He-Yu JIN Gen-Ming ZHANG Bao-Guo XIAO Zhi-Gang DUAN Li-Min WEI Zhi-Yong LI Zu-Yu LU Zhao-Hui LIU Yong-Ying CHEN Ke-Liang HU Rong-Jiang ZHU Hai-Dong CEN Ling WANG Su-Fang LI Xiang-Qing CHEN Tao HUA Hui 《中国物理C(英文版)》2001,25(8):731-735
Through the 20Na β+ 20Ne→16O+α process,the half-life and β+ delayed α decay spectrum of 20Na have been measured on the Radioactive Ion Beam Line in Lanzhou(RIBLL). The 20Na was identified through TOF-ΔE method and alpha particle was measured by four Si(Au) surface barrier detectors. The half life of 20 Na is(459±7)ms. Result shows that in addition to nine high excitation energy levels with Ed≥2.688MeV, three low excitation energy levels of 20Na with Ed=0.890 & 1.054,1.991,2.424 & 2.457MeV were observed in the experiment. The relative intensity for 1.991MeV level, a more important energy level in the center of mass system energy region from 1.6 to 2.5MeV obtained in this experiment is much higher than the existed one. We also obtained the relative intensities of the levels of Ed=0.890 & 1.054,2.424 & 2.457MeV. 相似文献
4.
5.
YU Yong XIE Yuan-Xiang XU Shu-Wei LI Zhan-Kui PAN Qiang-Yan WANG Chun-Fang XING Jian-Ping ZHANG Tian-Mei 《中国物理C(英文版)》2001,25(2):108-114
Isotopes,130Nd and 140Tb were produced using enriched targets 96Ru and 106Cd, respectively,bombarded by 36Ar ion beam. The two nuclides were identified and studied by a He-jet tape transport system in combination with "X-γ" and "γ-γ" coincidence measure- ments. The half-life of 130Nd was determined to be (13±2)s. The EC/β+ decay scheme of 130Nd was proposed for the first time, and the spins and parties of the ground-state and observed low-lying states in the daughter nucleus 130Pr were speculated tentatively. The previous simple EC/β+ decay scheme of 140Tb was revised, and the spin-parity of its groundstate was assigned to be 7+. 相似文献
6.
7.
Strongly damped reactions of 238U+238U, at Ecm= 680—1880 MeV have been studied based on the improved quantum molecular dynamics model. We find that at a certain energy region the entrance channel potential is weakly repulsive and the dissipation is very strong after touching configuration, these two effects make the time delay of re-separation for colliding system. The single particle potential well of the transiently formed composite system has Coulomb barrier about 15—20 MeV high at the surface, which makes the excited unbound protons being still embedded in the potential well and moving in a common mono-single particle potential for a period of time and thus restrains from quick decay of the composite system. 相似文献
8.
9.
We analyze the decay amplitudes of the process a2(1320)→π+π+π- using the tensor analysis method and show how to obtain three body amplitudes. 相似文献
10.
11.
BES Collaboration 《中国物理C(英文版)》2002,26(1):8-16
The decay mode of J/ψ→π03(π+π-) was studied very little before. There are no informations except branching ratios for this channel in PDG book which based on less than 0.2×106J/ψ events of MARKⅠ. Now, BESⅠ has a data sample of 7.8×106J/ψ events, we can make more accurate results than MARKⅠ. Total of 3290±43 J/ψ→π03(π+π-) events including 1275±86 J/ψ→ω2(π+π-) events are selected. J/ψ→π03(π+π-) and J/ψ→ω2(π+π-) events have been generated with MC simulition for calculating events selection efficiency. BESⅠ result is: Br(J/ψ→π03(π+π-))=(2.52±0.06±0.43)% and Br(J/ψ→π03(π+π-))=(1.31±0.09±0.21)%. Meanwhile, we studied the invariant mass of 4π and ωππ to find interesting signals. It seems that there is a peak at about 1.74GeV in the invarianat mass spectrum of 4π, and a enhancement was also found at about 1.9GeV in the invariant mass spectrum of ωππ. It is not clear whether they are from resonances or background. Therefore, more work in detail is still going on. 相似文献
12.
13.
Previous experimental results of (EC+β+) decay for the medium-heavy nuclei reported by our group since 1996, including 153Er, 157Yb, 209Fr, 128Ce, 130Ce, and 128Pr have been briefly summarized. The observed low-lying states in their daughter nuclei have been reviewed in a systematic way and compared with different model calculations. Finally, some questions have been put forward for further study and discussion. 相似文献
14.
In the framework of the projected shell model, we investigate the competition between the two-quasineutron and two-quasiproton Kπ=6+ states in the ytterbium isotopes and N =104 isotones adjacent to 174Yb. The 174Yb results are compared with the experimental data.The Kπ =6+ isomer observed in 174 Yb is assigned as an admixture of the ν7/2-[514] ν5/2-[512] and π7/2+ [404]π5/2+ [402] intrinsic structure, which explains the experimental |g K-g R | value. Similar mixing would appear in 174 Yb, 176 Hf,and 178 W. The low-lying Kπ=6+ states are also predicted in 170-178 Yb. 相似文献
15.
16.
Franck--Condon factors and r-Centroids for the A 1∑+u-X1∑+g Band System of 107,109Ag2: Comparison of the Observed and Calculated Absorption Band Strengths 下载免费PDF全文
A.Antic-Jovanovic M.Kuzmanovic V.Bojovic Murtadha A.Khakoo Russ R.Laher 《中国物理快报》2007,24(9):2566-2568
Franck-Condon factors and r-centrolds for the, A^1 ∑^+ u-X^1∑^+ 9 band system of ^107,109Ag2 are computed using Morse and Rydberg-Klein-Rees potentials for both lower and upper electronic states. The differences between the two sets of results are typically in the third decimal place for transitions involving vibrational levels with ν' and ν" up to about 15. Somewhat larger deviations appear for higher vibrational levels, but both sets of results follow the same pattern, which is to match well with the relative absorption band strength distribution in our experimental spectrum. The relative absorption band strengths are calculated by assuming that the electronic transition moment has only a weak dependence on the internuclear distance r. Good agreement between our measured and calculated absorption band strength ratios is found, which provides an excellent test of the calculated Franck- Condon factors and relative absorption band strengths. The r-centrold value for the (ν' = 0, ν" = 0) band is found to be approximately equal to the average value of r' and r''e , indicating that the potentials of both states are not significantly aaharmonic around their minimum regions. 相似文献
17.
本文主要介绍了入射离子能量为64和67MeV时,12C+197Au反应中出射的α粒子的能谱和角分布,以及能量为71.5MeV时该反应中出射的α、Be和B等粒子的能谱和角分布。给出了6Li粒子的产额和使用α-α粒子符合技术,在相对于东流方向成90°处测得的反应中出射的8Be分裂开的α粒子的能谱和产额。反应中出射的各种粒子的最可几能量,随着入射离子能量的降低而降低,角分布都是大约在擦边角附近出现峰值,当入射离子能量从71.5MeV降到64MeV时,其峰位大约从80°移到120°,显示出转移反应的特征。我们对实验结果作了一些简要的分析讨论。 相似文献
18.
BES Collaboration 《中国物理C(英文版)》1997,21(2):97-103
Using the BES data collected at √S=4.03GeV.the QED processes of e+e-→e+e-,μ+μ- have been studied. Our measurements agree with the QED prediction,and luminosities obtained from these two final states are compatible at a level of 4%.The total integrated luminosity of 23.1pb-1 was given for all data collected at this energy region from the calculation. 相似文献
19.
Xie Yuanxiang Xu Shuwei Guo Yingxiang Ma Ruichang Ge Yuanxiu Li Zhankui Wang Chunfang Guo Bin Xing Jianping Zhang Tianmei Zhu Shaofei Xu Wang 《中国物理C(英文版)》1997,21(4):289-291
209Fr has been produced by irradiation of 197Au with 16O from SFC accelarator uia the fusion-evaporation 4n channel.The(EC+β+)decay of 209Fr has been studied by a He-jet tape transport system.The decay scheme is proposed for the first time based on γ-t,X-γ-t,γ-γ-t coincidece and γ-γ delay coincidence measurements,which takes account of 20 observed γ ray.Five members of low-lying states in 209Rn can be explained by the multi-plet [(210Rn2+)(νf5/2)-1].The branching ratio for(EC+β+) decay of 209Fr has been estimated experimentaly to be(3.0±1.5)%. 相似文献
20.
In the structure function approach,we calculate the threshold behaviours for e++e-→τ++τ-,which including QED radiative corrections from initial correction,vacuum polarization effect,Coulomb effect and final state correction.This theoretical prediction for threshold behaviours of τ-pair production is useful for BES new measurement of lepton τ mass. 相似文献