Upsilon Photo-Production off Proton in QCD Inspired Model

Based on the generalized vector meson dominance model in QCD, we study photoproduction of vector meson T off the proton by use of the QCD inspired model in which the contributions from quark-quark, gluon-gluon, and quark-gluon interference term to observable are taken into consideration. Calculations are performed for total cross section σtot, differential cross section dσ/dt, ratio of the real part to imaginary part of forward scattering amplitude ρ, and nuclear slop parameter function β. The mediators of interactions between projectiles （the quark and antiquark pair fluctuated from the real the photon） and the proton target （three-quark system） are the tensor Glueball and Odderon instead of using the usual Pomeron exchange. The theoretical predictions for σtot （s） are consistent with the experimental data within error bars of the data. The data for dσ/dt, ρ, and β are urgently needed.     

中子俘获瞬发γ活化分析数据库

简要地介绍了热中子俘获瞬发γ射线数据的测量、评价、检验及其中子俘获瞬发γ射线活化分析数据库的研制、结构和基本数据内容等. The evaluation, measurement, and check of prompt γ-ray data for neutron capture are presented. The development of the database of prompt γ-ray activation analysis for neutron capture, and its structure and basical data are also described in the text.     

用直接中子法测量（n, 2n）反应截面的实验方法研究

在中国原子能科学研究院HI-13 串列加速器上的非常规多探测器快中子飞行时间谱仪上,采用直接中子法测量了14.3 MeV 中子与169Tm作用的(n,2n) 反应截面。用蒙特卡罗方法模拟了次级中子的产生,以对实验数据进行中子注量率衰减、多次散射和有限几何修正,同时结合SUNF 方法得到的评价能谱,给出了(n,2n) 反应截面的实验测量结果。测量截面以中子弹性散射微分截面作为标准截面来归一,并用反冲质子望远镜测量n-p 反应的反冲质子,以监视中子注量率。用直接中子法测量得到的结果与评价数据进行了比较,讨论了采用这种方法测量(n,2n) 反应截面的可行性。(n,2n) reaction cross section from 169Tm at 14.3 MeV was measured with the direct emittedneutron coincidence detecting method, using abnormal fast neutron TOF spectrometer on the HI-13 Tandem Accelerator at CIAE. Monte-Carlo method was used to simulate the generation of secondary neutron and correct the experimental data considering neutron flux attenuation, multiple scattering and finite geometry correction. Combining with evaluated spectra given by SUNF program, the experimental measurement results of the (n,2n) reaction cross sections were given. Cross sections of measurements were normalized by using neutron elastic scattering differential cross section as a standard section, and a recoil proton telescope was used to measure recoiling proton from the n-p reaction to monitor neutron flux rate. After comparing the experimental results with evaluated data, the feasibility of the direct emitted-neutron coincidence detecting method is discussed.     

Measurement of(n,α)and(n,2n)reaction cross sections at a neutron energy of 14.92±0.02 MeV for potassium and copper with uncertainty propagation

Experimentally measured neutron activation cross sections are presented for the ⁶⁵Cu(n,0)^62mCu,⁴¹ K(n,a)^38Cl,and ⁶⁵Cu(n.2n)⁶⁴Cu reactions with detailed uncertainty propagation.The neutron cross secions were measured at an incident energy of 14.92±0.02 MeV,and the neutrons were based on the(d,n)a fusion reaction.The ²⁷ Al(n,a)²⁴Na reaction was used as a reference reaction for the normalization of the neutron flux.The pre-calib-rated lead-shielded HPGe detector was used to detect the residues'γ-ray spetra.The data from the measured cross sections are compared to the previously measured cross sections from the EXFOR database,theoretically calculated cross sections using the TALYS and EMPIRE codes,and evaluated nuclear data.     

Cross Section of Heavy Ion Reaction （14.5 MeV/u） ^132Xe ＋ Bi

We investigate the cross section of the heavy ion reaction （14.5 MeV/u） ^132Xe ＋ Bi by using a CR-39 plastic track detector. The target-detector assembly is exposed at UNILAC beam facility of GSI, Germany. After etching under appropriate etching conditions, the detector is scanned for multipronged events produced as a result of interactions of projectile ions with target atoms. The elastic events are separated from binary events and used for the determination of the quarter-point angle. The quarter-point angle obtained is used to determine the total reaction cross section. The total experimental reaction cross section is determined by using statistics of inelastic events of two-pronged and higher multiplicity events. The experimental reaction cross sections determined by using elastic and inelastic data observed in the reaction under study are found to be in good agreement with the theoretically calculated value of reaction cross section using a sharp cutoff model.     

The excitation functions of ~(187)Re(n,2n)~(186m,g)Re reactions

A new value for the emission probability of 137.144 keV γ-rays from ~(186g)Re decay is recommended to be(9.47±0.03)/%.Using this value the measured cross sections for ~(187)Re(n,2n)~(186m)Re and ~(187)Re(n,2n)~(186g)Re reactions around 14 MeV are analyzed,and the cross section for ~(187)Re(n,2n)~(186+g)Re reaction at 14.8 MeV is(2213±116)mb.The UNF code was adopted to calculate the cross sections for the ~(187)Re(n,2n)~(186+g)Re reaction below 20 MeV,fitting to the value(2213±116) mb at 14.8 MeV using a set of optimum neutron optical potential parameters which were obtained based on the relevant experimental data of rhenium.The isomeric cross section ratio for the~(187)Re(n,2n)~(186,g)Re reaction was analyzed using the V-H method based on nuclear statistical theory.Combining these calculated results,the excitation functions for the ~(187)Re(n,2n)~(186m)Re and ~(187)Re(n,2n)~(186g)Re reactions were obtained.The obtained results are in good agreement with the available experimental data.     

Z′particles and e~+ e~- → τ~+ μ~-

We analyze the cross section of e + e-→τ + μ-within the frameworks of SM and its Z extension.The theoretical prediction of the SM on the total cross section is suppressed by the tiny neutrino masses.On the other hand,the contributions from Z to the cross section are enhanced drastically because of the tree level FCNC couplings among Z and leptons.     

14MeV中子引起的核反应截面测量中监督反应的研究

讨论了14MeV中子引起的核反应截面测量中监督反应对测量结果的影响,同时列出了常用的一些监督反应及参数,利用截面的评价值给出了一些监督反应的截面随中子能量变化的关系曲线,并对^27Al（n,p）^27Mg反应做了定性分析,说明了监督反应的选取对反应截面测量的重要性。 It was discussed in this article that the effects of different monitors in the cross section measurements of nuclear reactions induced by 14 MeV neutrons, at the same time some monitors and correlative parameters were listed. The excitation functions of monitors are taken from the evaluatied cross sections, and a qualitative analysis has been performed for ^27Al（n,p） ^27Mg reaction. It indicates that the choice of monitor is very important for cross section measurements     

Theoretical prediction of energy dependence for D+BrO→DBr+O reaction:The rate constant and product rotational polarization

A quasi-classical trajectory(QCT) calculation is used to investigate the vector and scalar properties of the D + Br O → DBr + O reaction based on an ab initio potential energy surface(X1A state) with collision energy ranging from 0.1 kcal/mol to 6 kcal/mol. The reaction probability, the cross section, and the rate constant are studied. The probability and the cross section show decreasing behaviors as the collision energy increases. The distribution of the rate constant indicates that the reaction favorably occurs in a relatively low-temperature region(T 100 K). Meanwhile, three product angular distributions P(θr), P(φr), and P(θr, φr) are presented, which reflect the positive effect on the rotational angular momentum j' polarization of the DBr product molecule. In addition, two of the polarization-dependent generalized differential cross sections(PDDCSs), PDDCS00 and PDDCS20, are computed as well. Our results demonstrate that both vector and scalar properties have strong energy dependence.     

Positron total cross sections for collisions with N2 and CO2 at 30-3000 eV

The total (elastic plus inelastic) cross sections for positron scattering from N2 and CO2 over the incident energy range from 30 to 3000eV are calculated using the additivity rule model at Hartree-Fock level.A complex optical model potential modified by incorporating the concept of bonded atom, which takes into account the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross section of positron-molecule scattering. The calculated total cross sections are in good agreement with those reported by experiments and other theories over a wide energy range.     

晕核6He（25 MeV/u）的单、双中子转移截面测量

实验测量了25 MeV/u 的6He+9Be反应中的单、双中子转移微分截面. 利用反应耦合道模型初步分析了实验数据, 计算大体重现截面值. 转移反应对末态有相当的选择性, 并且双中子转移截面主要来自到基态的一步过程. 后角度截面的上升可能与连续态的耦合有关. Differential cross sections for quasi elastic scattering at forward angles and for 1n and 2n transfer reaction at backward angles induced by 6He at 25 MeV/u from 9Be target were measured. The experimental data were analyzed in the framework of the CRC model. The raise at backward angle of the 1n and 2n transfer cross section can not reproduced by the current calculation.     

Positron total cross sections for collisions with N_2 and CO_2 at 30-3000 eV

The total (elastic plus inelastic) cross sections for positron scattering from N2 and CO2 over the incident energy range from 30 to 3000eV are calculated using the additivity rule model at Hartree-Fock level. A complex optical model potential modified by incorporating the concept of bonded atom, which takes into account the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross section of positron-molecule scattering. The calculated total cross sections are in good agreement with those reported by experiments and other theories over a wide energy range.     

Absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence

By using the partial wave method,we investigate the absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence.We obtained the expression of absorption cross section σabs(ω)=π/ω2sum from l=0 to ∞(2l+1)|Tωl(ω)|2=π/ω2sum from l=0 to ∞(2l+1)Γωl(ω).Then we numerically carry out the absorption cross section and we find that the larger the angular momentum quantum number l is,the smaller the corresponding maximum value of the partial absorption cross section is,and that the total absorption cross section tends to the geometric-optical limit σ hf abs ≈πb 2 c.We also find that higher value of ω q(state parameter of quintessence) corresponds to the higher value of absorption cross section σ abs.     

核子-核子碰撞截面的参数化公式

核子-核子碰撞截面(σ_NN)是描述原子核反应模型中的重要物理量。 核子-核子碰撞截面包括质子-质子碰撞截面（σ_pp）、中子-中子碰撞截面（σ_NN）和中子 质子碰撞截面（σ_np）, 它们随着核子能量与核物质密度的改变而变化。人们在目前研究中提出了多种核子-核子碰撞截面关于能量和核物质密度的参数化公式,通过计算12C+12C的完全反应截面,比较了不同入射能量下使用各种核子-核子碰撞截面参数化公式对12C完全反应截面的影响。 The nucleus-nucleus cross sections(σ_NN) include the proton-proton cross section, neutron-neutron cross section, and neutron-proton cross section. σ_NN change with the variations of the incident energies and the densities. Some parameterizations of σ_NNas a function of incident energy and density have been proposed in the theoretical and experimental study of nuclear reactions. Through the calculation of reaction cross sections of 12C+12C at different energies, the effect of different σ_NN parameterizations in the reaction cross sections of 12 are studied.      

Elastic scattering of two ground-state N atoms

An interaction potential for an N₂(X¹σ_g⁺) molecule is constructed by using the highly accurate valence internally contracted multireference configuration interaction method and the largest basis set, aug-cc-pV6Z, in the valence range. The potential is used to investigate the elastic scattering of two N atoms at energies from 1.0× 10^-11 to 1.0× 10^-4 a.u. The derived total elastic cross sections are very large and almost constant at ultralow temperatures, and the shape of total elastic cross section curve is mainly dominated by the s-partial wave at very low collision energies. Three shape resonances are found in the total elastic cross sections. Concretely, the first one is very sharp and strong. It results from the g-partial-wave contribution and the resonant energy is 3.645× 10^-6 a.u. The second one is contributed by the h-partial wave and the resonant energy is 1.752× 10^-5 a.u. This resonance is broadened by those from the d- and f-partial waves. The third one comes from the l = 6 partial wave contribution and the resonant energy is 3.522× 10^-5 a.u. This resonance is broadened by those from the g- and h-partial waves. The N₂(X¹σ_g⁺) molecular parameters, which are determined at the current theoretical level, achieve very high accuracy due to the employment of the largest correlation-consistent basis set in the valence range.     

Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction

Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering.     

Measurement of 59Co(ai,x)reaction cross sections with the fast neutrons based on the 9Be(p,n)reaction

The cross sections of the ⁵⁹Co(n,x)reaction in the average energy range of 15.2-37.2 MeV were meas-ured using activation and an off-line γ-ray spectrometric technique.The neutrons were generated from the ⁹Be(p,n)reaction with proton beam energies of 25-45 MeV at the MC-50 Cyclotron facility of the Korean Institute of Radi-ological and Medical Sciences(KIRAMS).Theoretical cal lculations of neutron-induced reactions on ⁵⁹Co were per-formed using the nuclear model code TALYS-1.9.The results for the ⁵⁹Co(n,x)reactions were compared with the theoretical values obtained using TALYS-1.9 and the literature data provided in EXFOR and the TENDL 2019 nuc-lear data library.The theoretical values obtained using TALYS-1.9 with adjusted parameters are comparable to the experimental data.The measured reaction cross sections of a few radionuclides are new,and the others are compar-able to the literature data,and thus,they can strengthen the database.The present study on cross sections leads to useful insight into the mechanisms of ⁵⁹Co(n,x)reactions.     

Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar^16＋ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization （SI） to single capture （SC） is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u..     

Multiple ionization of Ne induced by 10keV/u-500keV/u C~(q+)(q=13)ions

The values of cross-section ratio Rk1 of direct k-fold ionization cross section(σk) to direct single ionization cross section(qσ1) of Ne impacted by C+(q = 1–3) ions in an energy range of 10 ke V/u–500 ke V/u are measured in this work.The experimental data are compared with the results from our multi-electron classical over-barrier ionization(ME-COBI)model,showing that the model can give a good estimate to the experimental data.     

Theoretical study of stereodynamics for the D'+ DS(v=0,j=0) → D'D + S abstraction reaction

Quasiclassical trajectory (QCT) calculations have been performed for the abstraction reaction, D'+ DS(v = 0, j = 0) → D'D + S on a new LZHH potential energy surface (PES) of the adiabatic 3 A electronic state [Lü et al. 2012 J. Chem. Phys. 136 094308]. The collision energy effect on the integral cross section and product polarization are studied over a wide collision energy range from 0.1 to 2.0 eV. The cross sections calculated by the QCT procedure are in good accordance with previous quantum wave packet results. The three angular distribution functions, P(θr), P(φr), and P(θr,φr), together with the four commonly used polarization-dependent differential cross sections ((2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21/dωt)) are obtained to gain insight into the chemical stereodynamics of the title reaction. Influences of the collision energy on the product polarization are exhibited and discussed.