The angular distributions of elastic scattering of 12,13C+Zr

To obtain the neutron spectroscopic amplitudes for \begin{document}${}^{90-96}$\end{document}Zr overlaps, experimental data of elastic scattering with small experimental errors and precise optical potentials were analyzed. In this study, the elastic scattering angular distributions of \begin{document}${}^{12,13}$\end{document}C + \begin{document}${}^{A} {\rm{Zr}}$\end{document} (A = 90, 91, 92, 94, 96) were measured using the high-precision Q3D magnetic spectrometer in the Tandem accelerator. The S?o Paulo potential was used for the optical potential. The optical model and coupled channel calculations were compared with the experimental data. The theoretical results were found to be very close to the experimental data. In addition, the possible effects of the couplings to the inelastic channels of the \begin{document}${}^A {\rm{Zr}}$\end{document} targets and \begin{document}${}^{12, 13}$\end{document}C projectiles on the elastic scattering were studied. It was observed that the couplings to the inelastic channels of the \begin{document}${}^{12,13}$\end{document}C projectiles could improve the agreement with the experimental data, while the inelastic couplings to the target states are of minor importance. The effect of the one-neutron stripping in the \begin{document}${}^{13}$\end{document}C+\begin{document}${}^A {\rm{Zr}}$\end{document} elastic scattering was also studied. The one-neutron stripping channel in \begin{document}${}^{13}$\end{document}C + \begin{document}${}^A {\rm{Zr}}$\end{document} was found to be not relevant and did not affect the elastic scattering angular distributions. Our results also show that in the reactions with the considered zirconium isotopes, the presence of the extra neutron in \begin{document}${}^{13}$\end{document}C does not influence the reaction mechanism, which is governed by the collective excitation of the \begin{document}${}^{12}$\end{document}C core.     

6Li与核弹性散射的微观光学势

从基本的Dirac-Brueckner-Hartree-Fock微观理论出发,得到同时包含实部和虚部的核子-核散射的微观光学势,并利用折叠模型直接获得了核-核散射参数无关的整体微观光学势.考虑到核-核散射去弹过程高级项的贡献和⁶Li的碎裂效应,在微观光学势的实部和虚部中引入了修正因子N_R,N_I.系统研究了入射粒子⁶Li与靶核¹²C,²⁸Si,关键词： 弹性散射 Dirac-Brueckner-Hartree-Fock方法 折叠模型 微观光学势     

New measurements of the masses of 15B and 19N

The neutron-rich nuclei ¹⁵B and ¹⁹N have been produced in reactions between ¹⁸O and ⁴⁸Ca. Mass excesses of 28.968 ± 0.025 MeV and 15.872 ± 0.020 MeV respectively were deduced from the reaction Q-values. These results are compared with previous measurements and theoretical predictions. Updated predictions using two different mass formulae are presented.     

The 26Mg(14N, 10B)30Si and 26Mg(14N, 11B)29Si reactions

Reactions induced by ¹⁴N on ²⁶Mg at bombarding energies of 60–95 MeV have been studied. Angular distributions for states populated in ²⁹Si by the (¹⁴N, ¹¹B) reaction and in ³⁰Si by the (¹⁴N, ¹⁰B) reaction have been compared with Hauser-Feshbach and DWBA calculations to determine the reaction mechanism and to deduce spectroscopic information. The cross sections for the states populated in ²⁹Si and ³⁰Si are in poor agreement with statistical model calculations, indicating a non-compound nucleus mechanism.     

Calculation of scattering parameters for ultracold ~6 Li-~7 Li elastic collisions

This paper theoretically studies the elastic scattering properties in a mixture of 6 Li and 7 Li atoms at cold and ultracold temperatures.Based on the constructed accurate interatomic potential of the triplet state for 6 Li 7 Li mixture by the mass scaling method,it calculates the interspecies s-wave scattering lengths and the p-wave scattering lengths by the variable phase method and the semiclassical method,respectively.The scattering length is in good agreement with the experiment.The partial-wave and total cross sections are also calculated and a rich resonance structure is found.     

Global optical model potential describing 12C-nucleus elastic scattering

We construct a new global optical model potential to describe the elastic scattering of ¹²C. The experimental data of elastic-scattering angular distributions and total reaction cross sections for targets from ²⁴Mg to ²⁰⁹Bi are considered below 200 MeV within the framework of the optical model. The results calculated using the derived global optical potential are then compared with the existing experimental data. The reliability of the global optical potential is further tested by predicting the elastic scattering data out of the mass and energy ranges, within which the global potential parameters are determined, and reasonable results are also obtained.     

Polarization of 12B in deep-inelastic heavy-ion reaction 100Mo(14N, 12B)

Spin polarization of ¹²B was measured for ¹⁰⁰Mo(¹⁴N, ¹²B) at $\text{E}{}_{\mathrm{<mtext>i</mtext>}}\text{(}{}^{14}\text{N}\text{) ? 200}\text{MeV}$ as a function of $\text{Q}$ value down to $\text{Q ? ?150}\text{MeV}$, and was found anti-parallel to $\text{k}{}_{\mathrm{f}}\text{×}\text{k}{}_{\mathrm{i}}$ in the deep-inelastic region. The data together with those at lower incident energies show a systematic trend in $\text{Q}$-value dependence of the polarization.     

Study of ~3He inelastic scattering on 13C and 14C at 37.9 MeV

The differential cross sections of elastic and inelastic scattering of ~3He ions on ~（13）C and ~（14）C have been studied at an energy of 37.9 MeV with a double folding model based on M3Y-Reid effective nucleon-nucleon interaction.The resulted parameters have been used for the standard Distorted Wave Born Approximation calculations of angular distributions corresponding to different excitations levels of ~（13）C and ~（14）C and deformation parameters have been deduced.     

Structure study of 12B from the elastic scattering of neutrons from 11B

Differential cross sections for neutrons scattered from ¹¹B have been measured for 2.2 MeV < E_n < 4.5 MeV. The differential cross section σ(θ) is fitted reasonably well by R-matrix parameters for broad states in ¹²B with assignments 1 ^? and (1) ⁺ at excitation energies E_x = 5.8 and 6.8 MeV respectively. The broad 1 ^? state has not been previously observed and is believed to be the 1 ^? member of the $\text{1}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{1}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ particle-hole multiplet predicted to exist by earlier shell model calculations. Its existence completes the identification of all of the levels of this multiplet (3 ^?, 2 ^?, 4 ^?, 1 ^?). The broad (1)⁺ level at E_x = 6.8 MeV has not been previously observed. States at excitation energies E_x = 5.61, 5.73 and 6.6 MeV have been assigned spins and parities of 3⁺, 3^? and (1)⁺ respectively. These states had previously been assigned spins of 2, 3 and $\text{≧ 1}$ respectively. Work on T = 1 states in ¹²C¹ has been compared with the present work.     

Simulation of 12C+12C elastic scattering at high energy by using the Monte Carlo method

The Monte Carlo method is used to simulate the ¹²C+¹²C reaction process. Taking into account the size of the incident ¹²C beam spot and the thickness of the ¹²C target, the distributions of scattered ¹²C on the MWPC and the CsI detectors at a detective distance have been simulated. In order to separate elastic scattering from the inelastic scattering with 4.4 MeV excited energy, we set several variables: the kinetic energy of incident ¹²C, the thickness of the ¹²C target, the ratio of the excited state, the wire spacing of the MWPC, the energy resolution of the CsI detector and the time resolution of the plastic scintillator. From the simulation results, the preliminary establishment of the experiment system can be determined to be that the beam size of the incident ¹²C is φ 5 mm, the incident kinetic energy is 200-400 A MeV, the target thickness is 2 mm, the ratio of the excited state is 20%, the ight distance of scattered ¹²C is 3 m, the energy resolution of the CsI detectors is 1%, the time resolution of the plastic scintillator is 0.5%, and the size of the CsI detectors is 7 cm×7 cm, and we need at least 16 CsI detectors to cover a 0° to 5° angular distribution.     

Semiclassical analysis of the spin polarization of 12B in the 100Mo(14N, 12B)102Ru reaction

Polarization of ¹²B in the ¹⁰⁰Mo(¹⁴N, ¹²B)¹⁰²Ru reaction at 90 MeV incident energy is studied on the basis of the semiclassical theory of transfer reactions proposed by Brink. Gross behaviors of both the polarization and the cross section as functions of product kinetic energy can be predicted successfully by the theory. But disagreement in the numerical values of the polarization is found for low-energy ¹²B.     

Accurate calculation of the elastic scattering properties of ^7Li atoms at ultralow temperatures

The elastic scattering properties for collisions between two ^7Li atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybrid potentials for the singlet X^1 ∑g^＋ and triplet a^3 ∑u^＋ ground states of the Li2, Our calculated values for the scattering lengths α and the effective ranges re are compared with previous ones, and found them to be in good agreement. The scattering lengths are 34.6α0 for the singlet state and -27.6α0 for the triplet state. Shape resonances occur in the collisions at low energies. We also calculate the total cross sections and the energy positions of shape resonances for both X^1 ∑g^＋ and a^3 ∑u^＋ states.     

Study of ~3He inelastic scattering on ~(13)C and ~(14)C at 37.9 MeV

The differential cross sections of elastic and inelastic scattering of ³He ions on ¹³C and ¹⁴C have been studied at an energy of 37.9 MeV with a double folding model based on M3Y-Reid effective nucleon-nucleon interaction. The resulted parameters have been used for the standard Distorted Wave Born Approximation calculations of angular distributions corresponding to different excitations levels of ¹³C and ¹⁴C and deformation parameters have been deduced.     

Angular distributions of neutron polarization from the 14C(p,n)14N and 11B(α, n)14N reactions and R-matrix analysis oF 15N in the excitation-energy range between 11.5 and 12.5 MeV

Angular distributions of neutron polarization from the ¹⁴C(p, n)¹⁴N and ¹¹B(α, n)¹⁴N reactions have been studied for the particle energies E_p = 1.788, 2.025, 2.272 and 2.450 MeV, and E_α = 2.049 MeV. The polarization was derived from the left-right asymmetry induced by elastic scattering from ⁴He. Together with existing measurements of angular distributions and total cross sections for several reaction channels leading to ¹⁵N with an excitation energy between 11.5 and 12.5 MeV, these data were used to deduce from R-matrix analysis a set of resonance parameters for the ¹⁵N levels in this energy range.     

Beta-ray spectra of 12B and 12N and conserved vector current

In order to investigate spectral shape factors of ¹²B and ¹²N, we make a new formalism of β-decay theory, where the radial wave functions of leptons are treated with no approximation and, therefore, the nuclear matrix elements are electron-energy dependent. With this formalism we can show strong support for the conserved vector current hypothesis in analyzing the experimental data which were given by Wu, Lee and Mo in 1963 and revised by them in 1977 using the latest experimental results on the end-point energies and branching ratios of the inner β-groups, in addition to the correct Fermi functions for the positron. In fact, the average slopes of the spectral shape factors for ¹²B and ¹²N are in excellent agreement with those in our theory. Recent experimental data given by the Heidelberg group are also in good agreement with the theory if we analyze the difference of the average slopes for ¹²B and ¹²N. There are, however, small discrepancies with the theory in their individual values. The relation of the present formalism with traditional theories of β-decay is discussed.     

Effects of relativistic kinematics in heavy ion elastic scattering

Relativistic corrections to the reaction kinematic parameters were made for elastic scattering of ⁶Li, ¹²C and ⁴⁰Ar from ⁴⁰Ca, ⁹⁰Zr and ²⁰⁸Pb targets at incident energies between 20 and 100 MeV/nucleon. The results of optical model calculations show that the effects of such corrections are important when describing the angular distributions of elastic scattering cross sections for heavy ion scattering at incident energies as low as around 40 MeV/nucleon. The effects on the total reaction cross sections on the other hand, were found to be small within the energy range studied when the optical model potential is fixed.     

122~125Sn中子谱因子的实验研究

多个Sn同位素位于慢速中子俘获（s-）过程路径上,其中子谱因子可用于计算ASn（n,γ） A+1Sn直接辐射俘获的天体物理反应率,并可研究Sn同位素对s-过程核合成的贡献。本工作在中国原子能科学研究院HI-13串列加速器Q3D磁谱仪上,对实验室系下8°~66°范围内的122,124Sn（d,p）和（p,d）单中子转移反应角分布进行了测量。利用DWBA理论计算了转移反应角分布,并提取了122-125Sn的基态以及123,125Sn第一激发态的中子谱因子。其中,122Sn和124Sn的基态中子谱因子是首次从实验上获得。由于本工作成功鉴别开了123,125Sn的基态和第一激发态的效应,因此给出的谱因子比前人的结果更可信。Several Tin isotopes are on the path of slow neutron capture (s-) process, and the direct components of (n, γ) reactions can be derived from their neutron spectroscopic factors. In the present work, the angular distributions of 122,124Sn(p, d) and (d, p) reactions are obtained using the high-precision Q3D magnetic spectrograph in Beijing HI-13 tandem accelerator in China Institute of Atomic Energy. The distorted-wave Born approximation (DWBA) calculations are performed to extract the neutron spectroscopic factors of the ground state of 122-125Sn and the first excited state of 123,125Sn. The neutron spectroscopic factors of the ground state of 122Sn and 124Sn are firstly obtained in this work. As the events of the ground state and first excited state of 123,125Sn can be distinguished clearly by our experiment, the neutron spectroscopic factories of 123,125Sn are more reliable.     

Ab initio calculations on the α^3∑u^＋ state properties of dimer ^7Li2

The comparison between single-point energy scanning （SPES） and geometry optimization （OPT） in determining the equilibrium geometry of the α^3∑u^＋ state for ^7Li2 is made at numerous basis sets such as 6-311＋＋G（2df）, cc-PVTZ, 6-311＋＋G（2df, p）, 6-311G（3df,3pd）, 6-311＋＋G（2df,2pd）, D95（3df,3pd）, 6-311＋＋G, DGDZVP, 6-311＋＋G（3df,2pd）, 6-311G（2df,2pd）, D95V＋＋, CEP-121G, 6-311＋＋G（d,p）, 6-311＋＋G（2df, pd） and 6-311＋＋G（3df,3pd） in full active space using a symmetry-adapted-cluster/ symmetry-adapted-cluster configuration-interaction （SAC/SAC=CI） method presented in Gaussian03 program package. The difference of the equilibrium geometries obtained by SPES and by OPT is reported. Analyses show that the results obtained by SPES are more reasonable than those obtained by OPT. We have calculated the complete potential energy curves at those sets over a wide internuclear distance range from about 3.0α0 to 37.0α0, and the conclusion is that the basis set cc-PVTZ is the most suitable one. With the potential obtained at ccopVTZ, the spectroscopic data （Te, De, D0, ωe,ωeХe, αe and Be） are computed and they are 1.006 eV, 338.71 cm^-1, 307.12 cm^-1, 64.88 cm^-1, 3.41 cm^-1, 0.0187 cm^-1 and 0.279 cm^-1, respectively, which are in good agreement with recent measurements. The total 11 vibrational states are found at J=0. Their corresponding vibrational levels and classical turning points are computed and compared with available RKR data, and good agreement is found. One inertial rotation constant （By） and six centrifugal distortion constants （Dr Hv, Lv, My, Nv, and Ov） are calculated. The scattering length is calculated to be -27.138α0, which is in good accord with the experimental data.     

Pion-proton elastic scattering at 200 GeV/c

Recent measurements of differential and elastic cross-sections, slope parameters and ratios of the real and imaginary parts of the forward scattering amplitudes for pion-proton elastic scattering at 200 GeV/c have been fitted by using a simple Regge pole model with phenomenological residue functions. The computed results for total cross-sections have also been compared with the experimental data.     

Proton radii determinations from the ratio of π+ elastic scattering from 11B and 12C

A new method using low energy π⁺ elastic scattering is employed to determine the proton matter distribution of a nucleus relative to an adjacent nucleus differing by one proton. The difference in the rms charge radii of ¹²C and ¹¹B was determined to be 0.072 ± 0.021 fm with π⁺ beam energies of 38.6 and 47.7 MeV.