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1.
The ^8Li(p, d)^7 Li reaction plays an important role in the inhomogeneous Big Bang nucleosynthesis and in the seed-nuclide production phase for the r-process. For the first time, its angular distribution at backward angles was measured in inverse kinematics at Ec.m.=4.0 MeV by using an ^8Li secondary beam. The result of measurement includes the contributions of ^8Li(p, d0)^7Li and ^8Li(p, d1)^7Li^*. The ^8Li(p, d0)^7Li component is estimated to be 40%-58% in the mixture angular distribution by analysing the measured result. 相似文献
2.
GUO Xin-Heng KE Hong-Wei LI Xue-Qian LIU Xiang ZHAO Shu-Min 《理论物理通讯》2007,48(3):509-518
The newly observed D^*aj family containing D^*aj(2317), Daj(2460), and Daj(2632) attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model (the harmonic oscillator model) to evaluate the production rate of D^*aj (2317) from the decays of ψ(4415). For a comparison, we a/so employ the widely adopted heavy quark effective theory to repeat the calculation. We lind that the rate is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of Da(1968). Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space. 相似文献
4.
Rotational and Vibrational State Distributions of CsH and Relative Reactivity in Reactions of Cs(6^2D,7^2D) with H2 下载免费PDF全文
By using a pump-probe technique, the nascent rotational and vibrational state distributions of CsH are obtained in the Cs(6^2 D,7^2 D) plus H2 reaction. The nascent CsH molecules are found to populate the lowest two vibrational (v″ = 0 and 1) levels of the ground electronic state. By comparing the spectral intensities of the CsH action spectra with those of pertinent Cs atomic fluorescence excitation spectra, the relative reactivity with 1-12 is in an order of6^2D3/2 〉 6^2D5/2 〉 7^2D3/2 〉 7^2D5/2. The rotational temperatures are found to be slightly below the cell temperature. The relative fractions (〈fV〉, 〈fR〉, 〈fT〉) of average energy disposal are derived as (0.2,0.12,0.68), (0.2,0.12,0.68), (0.07,0.04,0.89) and (0.07,0.04,0.89) for the 6^2D3/2, 6^2D5/2, 7^2D3/2 and 7^2D5/2, respectively. The major available energy is released as translation. These results support that the reaction mechanism of Cs(6^2 D,7^2 D) plus 112 is primarily a eollinear abstraction and not an insertion. 相似文献
5.
We employ a direct capture method to study the influence of D-state in ^4He on S factor for the ^2H(d,γ)^4He reaction, in which the D-state component of the colliding deuterons and D-state component in ^4He ground state are considered. The parameters of Woods-Saxon (WS) potentials are obtained by reproducing the binding energy of d-d (i.e. ^2H-^2H) system, and d-d elastic scattering phase shifts calculated by the resonating group method. The theoretical results are in good agreement with the experimental data at Ec.m〈 3 MeV. The impact of the D state probability in ^4He on the extrapolated value of the astrophysical S factor for ^2H(d, γ)^4He reaction is discussed. 相似文献
6.
7.
Based on the assumption of two-quark structure of the scalar meson K0^*(1430), we calculate the CP-averaged branching ratios for B→K0^*(1430)η(') decays in the framework of the perturbative QCD (pQCD) approach here. We perform the evaluations in two scenarios for the scalar meson spectrum. We find that: (a) the pQCD predictions for Br(B→K0^*(1430)η(')) which are about 10^-5 10^-6, basically agree with the data within large theoretical uncertainty; (b) the agreement between the pQCD predictions and the data in Scenario Ⅰ is better than that in Scenario Ⅱ, which can be tested by the forthcoming LHC experiments; (c) the annihilation contributions play an important role for these considered decays. 相似文献
8.
Low-energy scattering of D ^*+ and D1^0 meson is studied using quenched lattice QCD with improved lattice actions on anisotropic lattices.The threshold scattering parameters,namely the scattering length a 0 and the effective range r 0,for the s-wave scattering in J P = 0 - channel are extracted: a 0 = 2.52(47) fm and r 0 = 0.7(1) fm.It is argued that,albeit the interaction between the two charmed mesons being attractive,it is unlikely that they can form a shallow bound state in this channel.Our calculation provides some useful information on the nature of the newly discovered resonance-like structure Z + (4430) by the Belle Collaboration. 相似文献
9.
The angular distributions of the charge exchange reaction ^1H(^6He,^6Li)n were measured in reverse kinematics with a secondary ^6He beam at the energy of 4.17 A MeV.The data were analysed in the context of a microscopic calculation.It is shown that both the ground state of ^6He and the second excited state of ^6Li(3.563MeV,0^ ) have a halo structure. 相似文献
10.
A Higgs-Yang-Mills monopole scattering spherical symmetrically along light cones is given. The left incoming anti-self-dual α plane fields are holomorphic, but the right outgoing SD β plane fields are antiholomorphic, meanwhile the diffeomorphism symmetry is preserved with mutual inverse afiine rapidity parameters μ and μ^-1. The Dirac wave function scattering in this background also factorized respectively into the (anti)holomorphic amplitudes. The holomorphic anomaly is realized by the center term of a quasi Hopf algebra corresponding to an integrable conformal affine massive field. We find explicit Nahm transformation matrix (Fourier Mukai transformation) between the Higgs YM BPS (fiat) bundles (1) modules) and the affinized blow up ADHMN twistors (perverse sheafs). Thus we establish the algebra for the 't Hooft Hecke operators in the Hecke correspondence of the geometric Langlands program. 相似文献
11.
We investigate the high resolution absorption spectroscopy of P2 radical, generated in ac glow discharge of PC13 buffered with helium, using optical heterodyne magnetic rotation enhanced concentration modulation spectroscopy in the visible region. The (1, 2), (1, 3) and (2, 3) bands of c^3Ⅱu- b^3Ⅱg in the range 16620-17860cm^-1 are observed and their 3II2 3II2 subbands are rotationally analysed. A set of effective molecular constants for the Ω= 2 component of the states involved are determined. 相似文献
12.
The spectra of light nuclei provide the first test of nuclear interaction models. The reaction amount determines the relative abundance of most elements in red giant stars, neutron stars, and black holes. Due to the fact that this reaction occurs at low energies, the experimental measurement is very difficult and perhaps impossible. In this work, the radiative capture of the ^12C(α, γ)^16O reaction at very low-energies is taken as a case study. Using the M3Y potential we calculate the astrophysical Factor for transition E1 and E2. In comparison with other theoretical methods and available recent experimental data, excellent agreement is achieved for the astrophysical S-factor of this process. 相似文献
13.
Quasi-classical trajectory theory is used to study the reaction of O(3p) with H2 (D2) based on the ground 3A″ potential energy surface (PES). The reaction cross section of the reaction O+H2→+OH+H is in excellent agreement with the previous result. Vector correlations, product rotational alignment parameters (P2(j′. k)) and several polarizeddependent differential cross sections are further calculated for the reaction. The product polarization distribution exhibits different characteristics that can be ascribed to different motion paths on the PES, arising from various collision energies or mass factors. 相似文献
14.
Analysis of prompt fission neutron spectrum and multiplicity for 237Np(n,f) in the frame of multi-modal Los Alamos model 下载免费PDF全文
The improved version of Los Alamos model with the multi-modal fission approach is used to analyse the prompt fission neutron spectrum and multiplicity for the neutron-induced fission of 237Np. The spectra of neutrons emitted from fragments for the three most dominant fission modes (standard Ⅰ, standard Ⅱ and superlong) are calculated separately and the total spectrum is synthesized. The multi-modal parameters contained in the spectrum model are determined on the basis of experimental data of fission fragment mass distributions. The calculated total prompt fission neutron spectrum and multiplicity are better agreement with the experimental data than those obtained from the conventional treatment of the Los Alamos model. 相似文献
15.
Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e + e  ̄ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K (*) l + l ̄ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K* l + l ̄ decay,we also measure the K* longitudinal polarization fraction and the di-lepton forwardbackward asymmetry. 相似文献
16.
The γ-rays and protons from an Ed = 20 keV deuteron beam incident on a D-Ti target were measured. A branching ratio of the 2H(d,γ)^4He reaction versus the ^2H(d,p)^3H reaction of Гγ/Гp = (1.061 0.34) x 10.7 has been obtained, and the astrophysical S factor of the ^2H(d,γ)He reaction at the center of mass energy Ecm ≈ 7 keV of (6.0±2.4) ×10^6 keV.b was deduced. 相似文献
17.
Determination of Astrophysical 13N(p,γ)^14O S-factors from the Asymptotic Normalization Coefficient of ^14C→^13C + n 下载免费PDF全文
The angular distribution of the ^13C(d,p)^14C reaction is reanalysed using the Johnson-Soper approach. The squared asymptotic normalization coefficient (ANC) of virtual decay ^14 C →^13 C^14+ n is then derived to be 21.4±5.0 fm^-1. The squared ANC and spectroscopic factor (SF) of ^14O→^13N +p are extracted to be 30.4± 7.1 fm^-1 and 1.94 ± 0.45, respectively. The astrophysical S-factors and reaction rates of ^13N(p, γ)140 are determined from the ANC of ^14O → ^13N + P using the R-matrix approach. 相似文献
18.
Temperature dependence of Cu20 orientations in the oxidation of Cu (111)/ZnO (0001) by oxygen plasma 下载免费PDF全文
The role of temperature on the oxidation dynamics of Cu20 on ZnO (0001) was investigated during the oxidation of Cu (111)/ZnO (0001) by using oxygen plasma as the oxidant. A transition from single crystalline Cu20 (111) orientation to micro-zone phase separation with multiple orientations was revealed when the oxidation temperature increased above 300 ~ C. The experimental results clearly show the effect of the oxidation temperature with the assistance of oxygen plasma on changing the morphology of Cu (111) film and enhancing the lateral nucleation and migration abilities of cuprous oxides. A vertical top-down oxidation mode and a lateral migration model were proposed to explain the different nucleation and growth dynamics of the temperature-dependent oxidation process in the oxidation of Cu (lll)/ZnO (0001). 相似文献
19.
The stereodynamics and reaction mechanism of the H′(^2S) + NH (X^3∑^-) → N(^4S) + H2 reaction are thoroughly studied at collision energies in the 0.1 eV-1.0 eV range using the quasiclassical trajectory (QCT) on the ground 4A″ potential energy surface (PES). The distributions of vector correlations between products and reagents P(φr), P(φr) and P(φr,φr) are presented and discussed. The results indicate that product rotational angular momentum j′ is not only aligned, but also oriented along the direction perpendicular to the scattering plane; further, the product H2 presents different rotational polarization behaviors for different collision energies. Furthermore, four polarization-dependent differential cross sections (PDDCSs) of the product He are also calculated at different collision energies. The reaction mechanism is analyzed based on the stereodynamics properties. It is found that the abstraction mechanism is appropriate for the title reaction. 相似文献