15O-15N,17F-17O库仑移位能

从Paris势和电磁相互作用出发,应用格林函数方法微观地计算了¹⁵O-¹⁵N,¹⁷F-¹⁷O库仑移位能.G矩阵的电荷非对称性的贡献较重要,比通常唯象的核力电荷非对称成分的贡献大一倍左右.     

Study of orientation characteristics of the 11B(5/2?, 4.445 MeV) nucleus in the 13C(d, αγ)11B reaction at Ed = 15.3 MeV

Double differential cross sections of the ¹³C(d, αγ)¹¹B(5/2⁻, 4.445 MeV) reaction were measured at E _d = 15.3 MeV. Angular dependences of the even components of density matrix spin tensors, magnetic sublevel populations, and components of multipole moment orientation tensors of the ¹¹B nucleus in this state were obtained. Experimental results were compared with theoretical data calculated under the assumption of different reaction mechanisms: deuteron pickup, heavy particle stripping, two-step mechanism of sequential cluster transfer, and compound nucleus formation.     

On the spin correlations of muons generated in the annihilation process e + e ? → μ+μ?

Using the technique of helicity amplitudes, the electromagnetic process e ⁺ e ⁻ → μ⁺μ⁻ is theoretically investigated in the one-photon approximation. The structure of the triplet states of the final (μ⁺μ⁻) system is analyzed. It is shown that in the case of unpolarized electron and positron the finalmuons are also unpolarized, but their spins are strongly correlated. Explicit expressions for the components of the correlation tensor of the final (μ⁺μ⁻) system are derived. The formula for the angular correlation at the decays of final muons μ⁺ and μ⁻, produced in the process e ⁺ e ⁻ → μ⁺μ⁻, is obtained. It is demonstrated that spin correlations of muons in the process of electron-positron pair annihilation have the purely quantum character, since one of the incoherence inequalities for the correlation-tensor components is always violated. The additional contribution of the weak interaction of lepton neutral currents through the virtual Z ⁰ boson is considered; it is established that, taking into account the weak interaction, the qualitative character of the muon spin correlations does not change. The text was submitted by the authors in English.     

α-decay study of 218Ac and 221Th in 40Ar+186W reaction

In this study,²¹⁸Ac and ²²¹Th nuclides were produced via the heavy-ion induced fusion evaporation reaction ⁴⁰Ar+¹⁸⁶W.Their decay properties were studied with the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system.The cross section ratio between ²²²Pa and ²¹⁸Ac was extracted experimentally,withmeasured value 0.69(9).Two new possible α decay branches to ²²¹Th are suggested.The valence neutron configurations for the daughter ²¹⁷Ra are discussed in terms of the hindrance factors.     

Investigation of the near-threshold (γ, n) reaction on the 116Cd and 121Sb nuclei

Isomeric yield ratios of ^115m,g Cd and ^120m,g Sb were measured in the (γ, n) reaction in the near-threshold region at γ-ray energies of 9.6, 9.8, 10.0, and 10.5 MeV. Experimental values of the isomeric yield ratios were compared with theoretical values calculated using the TALYS-1.0 program package. The (γ, n) reaction is shown to have a statistical character in the excitation region of residual nuclei 0.3–1.5 MeV.     

15N16O的激光磁共振谱与同位素分子15N17O和15N18O的光谱分析

采用内腔式饱和吸收技术获得Lamb凹陷,使CO激光磁共振谱仪的灵敏度及分辨率大大提高.利用该技术对自然丰度下¹⁵N¹⁶O的X²Π(υ=1)←X²Π(υ=0)塞曼跃迁进行测量,实现了包括Λ双分裂在内的各种精细结构的谱分辨.结合已发表的¹⁵NO同位素分子光谱实验数据进行分析计算,拟合得到迄今最完备、最精确的各相关同位素分子¹⁵N^mO(m=16—18)的结构参 关键词：     

Forbidden lines of the ν3 band of 13CH4: Ground-state constants

The ν₃ fundamental vibration-rotation band of carbon-13 enriched methane (¹³CH₄) was recorded using a high-resolution vacuum infrared grating spectrograph. Forbidden transitions of this band are reported for the first time. Of the nearly 900 transitions identified, 560 are forbidden transitions and 347 of the forbidden transitions have 11 ≤ J ≤ 18. Pairs of forbidden and allowed transitions having the same upper-state energy levels were used to calculate 550 independent differences between ground-state term values. From these data, a least-squares analysis was used to calculate the following values for ground-state structure constants and their standard deviations (in cm^?1):

$\text{β}{}^{\mathrm{O}}\text{hc}\text{= 5.240820 ± 0.000056}$

,

$\text{λ}{}^{\mathrm{O}}\text{hc}\text{=?(1.0856 ± 0.0015) × 10}{}^{\mathrm{?4}}$

,

$\text{?}{}^{\mathrm{O}}\text{hc}\text{= ?(1.4174 ± 0.0034) × 10}{}^{\mathrm{?4}}$

,

$\text{η}\text{hc}\text{= ?(1.73 ± 0.37) × 10}{}^{\mathrm{?11}}$

. The 550 values for the ground-state combination differences retained for analysis can be reproduced with an overall standard deviation of 0.0155 using the stated values for the structure constants. The note added in proof refines the above constants by including the newly observed microwave data.     

Determination of Astrophysical 13N(p,γ)14O S-factors from the Asymptotic Normalization Coefficient of )14C → 13C + n

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 ¹⁴C →¹³C + n is then derived to be 21.4 ± 5.0fm^-1. The squared ANC and spectroscopic factor (SF) of ¹⁴O → ¹³N + p are extracted to be 30.4 ± 7.1fm^-1 and 1.94 ± 0.45, respectively. The astrophysical S-factors and reaction rates of ¹³N(pγ)¹⁴O are determined from the ANC of ¹⁴O → ¹³N + p using the R-matrix approach.     

Magnetooptics of the 1D2 → 3F4 radiative transition in thulium:yttrium-aluminum garnet Tm3+:YAG

The spectra of luminescence and magnetic circular polarization of luminescence in the ¹ D ₂ → ³ F ₄ emission band in thulium:yttrium-aluminum garnet Tm³⁺:YAG (Tm³⁺:Y₃Al₅O₁₂) have been investigated at temperatures T = 78 and 293 K, respectively. Based on the analysis of the magnetooptical and optical spectra, the optical transitions between the Stark sublevels of the ³ F ₄ and ¹ D ₂ multiplets in Tm³⁺:YAG were identified. It is shown that the symmetry and energies of the Stark sublevels of the ³ F ₄, ¹ D ₂, and ³ H ₆ multiplets, found experimentally from magnetic and magnetooptical studies, confirm the results of theoretical calculations of the energy spectrum of the rare earth Tm³⁺ ion in YAG. Original Russian Text ? U.V. Valiev, J.B. Gruber, I.R. Gapdulkhakov, N.I. Juraeva, A.K. Mukhammadiev, Sh.A. Rakhimov, I.S. édel’man, 2009, published in Optika i Spektroskopiya, 2009, Vol. 106, No. 6, pp. 937–944.     

Isomeric yield ratios of the (γ, n) and (n, 2n) reactions on nuclei of 110Pd, 142Nd, and 144Sm

The isomeric yield ratios of the (γ, n) and (n,2n) reactions on nuclei of ¹¹⁰Pd, ¹⁴²Nd, and ¹⁴⁴Sm are measured by the induced radioactivity method. The energy dependence of the isomeric yield ratios of the photonuclear reactions ¹¹⁰Pd(γ, n)^{109m, g} Pd, and ¹⁴²Nd(γ, n)^{141m, g} Nd, and ¹⁴⁴Sm(γ, n)^{143m, g} Sm is investigated in the energy range 14–35 MeV. The results are compared to other published experimental data.     

Measurement of the hadronic decay current in τ?→π??+vτ

The properties of hadronic Z⁰ decays with final state photons, measured with OPAL at LEP, have been compared with predictions from two different matrix element calculations ofO( _s ). Two calculations, GNJETS and EEPRAD, have been investigated which use different schemes to restrict the phase space around the poles of the cross section. Assuming the E0-JADE jet definition, both calculations describe the data well in large regions of phase space fory _cut values around 0.06. For very large and very small jet-photon masses some deviations from the predictions have been found, indicating the importance of higher order corrections. Significant differences between the calculations are only apparent in the predicted rate of 1-jet plus photon events. The rate is higher in GNJETS which reproduces the data better than EEPRAD.     

Study of hot bands in the B2Σ+u-X2Σ+g system of C-2 anion

Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy was employed to observe the visible absorption spectra of the B^2Σ^+_u-X^2Σ^+_g electronic transition of C^-_2. Four hot bands (0,1), (1,2), (2,3) and (3,4) have been observed and the band (3,4) is measured directly for the first time, so far as we know, by absorption. A rotational analysis was carried out to obtain molecular constants. With the Franck－Condon principle and the vibrational Boltzmann distribution, we have estimated the vibrational temperature of C^-_2 to be about 3000K.     

Resonance states in 16O+16O, 12C+16O, α+16O and α+12C with modified Morse potentials

The resonance states in ¹⁶O+¹⁶O, ¹²C+¹⁶O, α+¹⁶O and α+¹²C are described using modified Morse potential proposed earlier whose success has already been demonstrated in the case of ¹²C+¹²C system. The general validity of such a potential with long range, shallow depth and repulsive soft core determined from the resonance data itself is being examined through the present study of the resonances in the above four systems. In each system, the experimental data of a large number of states have been successfully described with a modified Morse potential. The success points out a common mechanism of the origin of these states, and reaffirms authentically the diatomic-like rotational and vibrational picture of the nuclear molecular resonances proposed previously. The close resemblance between the physics of diatomic molecules and nuclear molecular resonances extending to the level of potential which is Morse type in both the cases — although belong to two different areas of physics — is further strengthened through the present study.      

Equation of State of 20Ne gas in the temperature-range 27–36 K

The many-body phase shifts for ²⁰Ne gas are calculated for low number densities in the temperature-range 27–36?K, using the Galitskii-Migdal-Feynman formalism. These phase shifts are inserted in the Beth-Uhlenbeck formula to determine the quantum second virial coefficient. This is compared to the classical coefficient as well as to the experimental values and other theoretical results. It is used to investigate the pressure-volume-temperature behavior of the gas and to compute other thermodynamic properties – the Helmholtz free energy, total internal energy, entropy, and specific heat capacity – for a number density of 1×?10²⁷ atoms/m³. Our results show that, in cooling and compressing the system, vapor-liquid condensation always occurs.     

Cross sections for monitor reactions 27Al((p, x)24Na, 27Al(p, x)22Na, and 27Al(p, x)7Be at proton energies in the range 0.04–2.6 GeV

The cross sections for the monitor reactions ²⁷Al(p, x)²⁴Na, ²⁷Al(p, x)²²Na, and ²⁷Al(p, x)⁷Be at 12 proton energies, 2605, 1598, 1199, 799, 600, 400, 249, 147.6, 97.2, 66.0, 44.6, and 40.8 MeV, have been determined with 72 × 72-mm square and 10.5-mm-diameter round aluminum foils. The rates of the reactions of the production of ²⁴Na, ²²Na, and ⁷Be in the foils in each irradiation run have been determined by γ spectrometry, whereas the number of protons transmitted through these foils has been determined using calibrated fast current transformers. The cross sections have been determined as the ratios of the corresponding reaction to the average proton fluence.     

11Li,14Be,17B的一个三体模型

假定¹¹Li,¹⁴Be和¹⁷B是由N=2Z核芯和两个外层中子组成的三体系统,核芯-中子和中子-中子间的作用为弱吸引指数势,不足以形成核芯-中子和中子-中子二体束缚态.本文的计算表明,核芯-中子-中子三体系统可形成束缚态,计算结果基本上解释了¹¹Li,¹⁴Be,¹⁷B的基态能量和异常大核半径的实验结果.     

Signals of α clusters in 16O+16O collisions at the LHC from relativistic hydrodynamic simulations

In relativistic heavy ion collisions, the fluctuations of initial entropy density convert to the correlations of final state hadrons in momentum space through the collective expansion of strongly interacting QCD matter. Using a (3+1)D viscous hydrodynamic program, CLVisc, we consider whether the nuclear structure, which provides initial state fluctuations as well as correlations, can affect the final state of heavy ion collisions, and whether one can find signals of α cluster structures in oxygen using final state observables in \begin{document}$ ^{16}\text{O}+{}^{16}\text{O} $\end{document} collisions at the CERN Large Hadron Collider. For the initial nucleon distributions in oxygen nuclei, we compare three different configurations, a tetrahedral structure with four-α clusters, the deformed Woods-Saxon distribution, and a spherical symmetric Woods-Saxon distribution. Our results show that the charged multiplicity as a function of centrality and the elliptic flow at the most central collisions using the four-α structure differs from those with the Woods-Saxon and deformed Woods-Saxon distributions, which may help to identify α clustering structures in oxygen nuclei.