共查询到20条相似文献,搜索用时 15 毫秒
1.
LI Yang-Guo 《中国物理C(英文版)》1989,13(2):148-155
The Lorentz invariant relativistic optical potential have been discussed at energies below 300MeV.The Dirac equation with scalar and vector potential is solved by exact partial wave method.The calculated results of proton 40Ca at energy region 300—65MeV are presented and compared with the experimental data of differential cross section dσ/dΩ,analyzing power Ay(θ) and spin rotation function Q(θ).It is shown that the impoved relativistic optical potential fits the data well. 相似文献
2.
WU Cui-E YE Yan-Lin JIANG Dong-Xing ZHENG Tao HUA Hui LI Zhi-Huan LI Xiang-Qing CHEN Zhi-Qiang HU Qing-Yuan ZHANG Gao-Long PANG Dan-Yang WANG Jia 《中国物理C(英文版)》2005,29(11):1052-1056
The reaction cross section, together with the one-, two- and three neutron removal cross sections, of 17C with the energy of 79A MeV on carbon target were measured using the radioactive beam line RIPS of RIKEN. The reaction cross section and the one-neutron removal cross section were analyzed within the frame of Glauber model. Both the analyses favor the dominant configuration of a 16C core (2+) plus a d5/2 valence neutron for 17C. The work for the neutron-rich carbon isotope on the reaction cross section σR and the interaction cross section σI on 12C target are summarized. 相似文献
3.
An Investigation of Relativistic Microscopic Optical Potential in Terms of Relativistic Brueckner-Bethe-Goldstone Equation
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Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation.The complex effective mass of a nucleon is determined by a fit to 200MeV p-40Ca scattering data.The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p-16O,40Ca,90Zr and 208Pb scattering in energy range from 160 to 180MeV.The microscopic optical potential is used to study the proton-40Ca scattering problem at 200MeV.The results,such as defferential cross section,analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential. 相似文献
4.
We have measured the reaction cross section σR of 17C on the carbon target at the intermediate energy of 97A MeV by using transmission method.finite-range Glauber model has been employed to investigate the density distribution of 17C by fitting the present result and the previous result of interaction cross section σI.By contrast with the result from the analysis of σI,a tail in the neutron density distribution of 17C is found necessary to interpret the present result.Considering the configuration of the valence neutron,a dominant 1d5/2(77±21%)occupancy is found,which is in agreement with results of momentum distribution measurements. 相似文献
5.
应用Dirac Brückner-Hartree-Fock方法, 采用新的G矩阵分解方式研究了核子在核介质中的同位旋相关的相对论微观光学势,采用定域密度近似得到有限核的相对论微观光学 势.讨论了有限核的相对论微观光学势及其Schrdinger等价势与入射质子能量的关系,计 算了200MeV以下质子入射4040Ca和208208Pb核的弹性散射角分布 和分析本领,得到了与实验相一致的结果,并将这种方法推广用于不稳定核的研究.通过对C a同位素的计算可以看出,在相
关键词:
相对论微观光学势
Dirac Brückner-Hartree-Fock
不对称核物质
定域密度近似 相似文献
6.
《Nuclear Physics A》1988,490(3):619-642
The relativistic microscopic optical potentials (RMOP) at E < 300 MeV have been derived and investigated based on Walecka's meson-nucleon model. An effective lagrangian including nucleon, σ- and ω-mesons, which is required to reproduce the nuclear matter saturation properties, has been introduced and used to calculate the self-energy of a nucleon in the nuclear medium. Systematical analyses of the scattering data are performed with the RMOP. Finally, several effects, such as the meson-nucleon vertex form factor, isovector meson exchanges, non-linear σ-model are studied. 相似文献
7.
We discuss the contributions of PGBs (technipions and top-pious) to the top quark production in TC2 theory at the high energy e+e- linear collider (LC) experiments. We find that the corrections to the production cross section σtt mathly come from top-pious. The corrections of the charged top-pious are significantly large in most of the parameter space. With reasonable value of the parameters, the correction to σtt can reach about 8% which may be detected at LC experiments. 相似文献
8.
Using a aerogel sample with introduced oxygen gas as a variable energy positronium source,the triplet to singlet conversion of positronium in the elastic and inelastic collisions between positronium atoms and oxygen molecules has been investigated with a time selecting energy spectrometer.We have found that the conversion cross section σ0—p is proportional to 1/v for slow positronium in the elastic collisons,where v is the mean velocity of positronium,and for the inelastic processes,the cross sections are estimated to be σ0—p=2.1×10-17cm2 and 6.6×10-18cm2 respectively at kinetic energies of positronium near two thresholds. 相似文献
9.
The fission cross sections and the evaporation residue cross sections for 12C+209Bi and 14N+Pb reactions were measured with the gold surface barrier silicon detectors and the mica nuclear track detectors.The critical angular momentum ler was deduced from the measured evaporation residue cross section σer on the basis of the sharp-off model.The fission barrier with the particular angular momentum i derived from the condition Γf/Γn=1 at l=le The angular momentum effect of the fission barrier was studied experimentally. 相似文献
10.
Initial State Interactions and J/ψ Production-Rate Suppression in High Energy P-A Collisions
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The influence of the initial state intcractions on the J/ψ production-rate supression in p-A collisions is studied. The incident proton energies decrease due to the inelastic interactions with the target nucleus. Considering energy loss of the incident proton,the data are well reproduced by using the final state interaction cross section σfabs=2.1mb. 相似文献
11.
CHEN Bao-Qiu 《中国物理C(英文版)》1993,17(4):345-352
In Dirac-Brueckner calculations for nuclear matter,the average binding energy per nucleon versus density curve is not uniquely defined if coupling to anti-particle is neglected.According to the Hugenholtz-Van Hove theorem,a constraint requires that the nucleon separation energy equals to the fermi energy at saturation density.Choosing saturation energy as empirical value EB/A=-15.8MeV,the self-consistent calculation leads to the saturation density kf=1.41fm-1 and effective mass m*=0.52m,in compressive coefficient k=208MeV.Applying the first law of thermodynamics,self-consistent effective mass (real scalar potential) and the binding energy per nucleon as function of the nuclear density can be obtained.With the realistic nucleon-nucleon interaction (Bonn potential),the vector potential can be obtained from solving the RBBG equation,which weakly depends on the momentum.The cross section and spin observables of the nucleon-nucleus scattering are studied with this new self-consistent relativistic microscopic optical potential. 相似文献
12.
We introduced an extended Glauber theory for a halo nucleus scattering, where the halo nucleons and the nuclear core were treated separately. Expressions of reaction and interaction cross sections of the halo nucleus scattering were derived. We took the halo structure of the projectile nucleus into account and adopted an improved optical limit approximation. In the framework of the extended Glauber theory, we studied the reaction cross section for the halo nucleus 14Be scattering on a target 12C. For comparison, the reaction cross sections of 12Be+12C were calculated as well. The density distribution of target 12C is taken from experiments, and those of the projectiles 12Be and 14Be were obtained by two methods. One is that the harmonic oscillator wave functions for 12Be and 14Be are used. The length of harmonic oscillator is adjusted to reproduce the reaction cross section of 12Be+12C at the high energy E=790MeV/u . The density distribution of 14Be was also calculated self-consistently in the relativistic mean field (RMF) theory, with a long tail wave functions for the two neutrons in 14Be. It was found that the calculated reaction cross sections for 12Be+12C at E=790MeV/u and E=56.5MeV/u were in good agreement with the experimental data no matter harmonic oscillator or RMF wave functions were used. In contrast, the experiments of the reaction cross sections for 14Be+ 12C could only be reproduced when the wave functions of two 2s1/2 neutrons spreaded over with a long tail. It comes to a conclusion that two outside neutrons in 14Be form a halo structure. 相似文献
13.
D. Jaque J. Capmany J. García Solé A. Brenier G. Boulon 《Applied physics. B, Lasers and optics》2000,70(1):11-14
This work reports for the first time continuous-wave laser action at room temperature around 1.3 7m in Nd3+ doped LiNbO3:ZnO. Optical spectroscopy has been used to determine the main laser characteristics of 4F3/24I13/2 channel, such as emission cross section and excited-state absorption cross section at laser wavelengths. Internal optical losses have been estimated from laser gain experiments. Under non-optimal conditions laser slope efficiencies of 30% have been obtained. 相似文献
14.
LI Yang-Guo 《中国物理C(英文版)》1992,16(2):137-144
If the antiproton optical potential is inclusive of the spin orbit interaction term,the A(p,p)A* inelastic scattering not only can excited the normal parity states,but also can excited the abnormal parity states.There are also induced the polarization Pf(θ) at the inelastic scattering.In the framework of DWIA,we derived the inelastic scattering cross section (dσ/dΩ)f,i,and polarization Pf(θ),and calculated the (dσ/dΩ)f,i, and Pf(θ) for 12C(p,p)12C* with 2+,3- and 1+ states at antiproton energies of 46.8 and 179.7MeV.They fited experiment data quite well.Due to the abnormal partity states in the inelastic process have been measured,the spin orbit term can not be neglect. 相似文献
15.
LIU Guan-Hua ZHAN Wen-Long ZHU Yong-Tai GUO Zhong-Yan HU Xiao-Qing XI Hong-Fei ZHOU Jian-Qun YIN Shu-Zhi FENG En-Pu ZHAO You-Xiong WEI Zhi-Yong FAN En-Jie 《中国物理C(英文版)》1993,17(2):166-172
The projectile-like fragments emittd from 46.7MeV/u 12C induced reactions have been measured.The most probable energies of the PLFs due to the projectile fragmentation can be reproduced within the Abrasion picture.Their parallel momentum distribution widths are found to fulfill the Goldhaber relation and the extraced reduced parallel momentum distribution width σ0 is 80±10MeV/c,which is close to the value obtained in the relativistic energy region.Futhermore,the values of σ0 are the same for different reaction systems in our experiment. 相似文献
16.
LU Zhao-Hui WU He-Yu HU Rong-Jiang ZHU Yong-Tai ZHANG Bao-Guo LI Zu-Yu WEI Zhi-Yong DUAN Li-Min WANG Hong-Wei XIAO Zhi-Gang WANG Su-Fang JIN Gen-Ming GUO Zh 《中国物理C(英文版)》2002,26(6):594-599
Under reverse kinematics, elastic scattering of 17F and 18Ne on proton is studied. The experimental differential cross sections were measured. A kind of global optical potential with the CH89 parameters is used to describe the radioactive nucleus as an initial optical potential parameters. The experimental differential cross section data are analyzed by using the theoretical calculation code DWUCK4 with the distorted wave Born approximation and parameter search subroutine ABOD which automatically searches the suitable parameters. Then the optical potential parameters of scattering 17F and 18Ne on proton are obtained. From the analyses of the optimized parameters, the real central potential mean square radii of 17F and 18Ne, 3.239fm and 3.317fm are deduced, respectively. 相似文献
17.
18.
LI Yang-Guo 《中国物理C(英文版)》1989,13(6):539-543
Elastic antiproton-nucleus scattering is analysed by a phenomenological optical model potential with spin orbit interaction.The elastic scattering differential cross section dσ/dΩ,polarization P(θ) and spin rotation function Q(θ) can be discribed by this potential.From the comparison with 12C nucleus experiment data of differential cross section and polarization,we obtain a more realistic antiproton optical potential. 相似文献
19.
V. Hejny P. Achenbach J. Ahrens R. Beck S.J. Hall M. Kotulla B. Krusche V. Kuhr R. Leukel V. Metag R. Novotny V. Olmos de León R.O. Owens F. Rambo A. Schmidt M. Schumacher U. Siodlaczek H. Ströher F. Wissmann J. Weiß M. Wolf 《The European Physical Journal A - Hadrons and Nuclei》1999,6(1):83-89
Photoproduction of - mesons from 4He has been measured for the first time. The experiment was performed at the Mainz Microtron (MAMI) using the TAPS photon spectrometer and the Glasgow/Mainz tagged photon facility. - mesons were identified in coincidence with recoil nucleons. Total and differential cross sections are presented in the photon energy range between threshold and 818 MeV. The exclusive data are used to determine the ratio of the elementary production cross sections on bound neutrons and protons, Cn/Cp = 0.68 - 0.02 - 0.09. In addition, upper limits for the total coherent cross section have been derived. 相似文献
20.
The η photon production reaction on nuclei is studied by employing N*(1535) resonance model. The parameters of the model are extracted by using experimental data of N* decay channels and fitting γp→ηp reaction cross section. The result shows that the theoretical values are in good agreement with experimental data if MN*=1550MeV. The total cross section of the η photoproduction on 12C is calculated. We find that the width of N*(1535) in nuclei increases because of corrections of many-body effects, and the interaction between N* and nuclei has the feature of repulsion. 相似文献