Quark model relation for kaon charge radii

We derive the equation r_E²(K⁰)/r_E²(K⁺) = m_s² − m_n²))/(2m_s² + m_n²) relating the kaon electric charge radii and the strange (m_s) and non-strange (m_n) quark masses in the nonrelativistic quark model, and suggest an inequality which we expect to hold in the presence of relativistic corrections. New data for these charge radii are presently being analysed by two experimental groups.     

Quark model for kaon nucleon scattering

Kaon nucleon elastic scattering is studied using chiral SU(3) quark model including antiquarks. Parameters of the present model are essentially based on nucleon–nucleon and nucleon–hyperon interactions. The mass of the scalar meson σ is taken as 635 MeV. Using this model, the phase shifts of the S and P partial waves of the kaon nucleon elastic scattering are investigated for isospins 0 and 1. The results of numerical calculations of different partial waves are in good agreement with experimental data.     

Garvey-Kelson relations for nuclear charge radii

The Garvey-Kelson relations (GKRs) are algebraic expressions originally developed to predict nuclear masses. In this paper we show that the GKRs provide a fruitful framework for the prediction of other physical observables that also display a slowly varying dynamics. Based on this concept, we extend the GKRs to the study of nuclear charge radii. The GKRs are tested on 455 out of the approximately 800 nuclei whose charge radius is experimentally known. We find a rms deviation of 0.01fm between the GK predictions and the experimental values. Predictions are provided for 116 nuclei whose charge radius is presently unknown.     

On the liquid drop model mass formulae and charge radii

An adjustment to 782 ground-state nuclear charge radii for nuclei with N, Z 3 \ge8 leads to R₀ = 1.2257 A^1/3\ensuremath R_0 = 1.2257 A^{1/3} fm and s \sigma = 0.124 fm for the charge radius. Assuming such a Coulomb energy E_c = \frac35 e²Z²/1.2257 A^\frac13\ensuremath E_c = \frac{3}{5} e^2Z^2/1.2257 A^{\frac{1}{3}} , the coefficients of different possible mass formulae derived from the liquid drop model and including the shell and pairing energies have been determined from 2027 masses verifying N, Z 3 \ge8 and a mass uncertainty ￡ \le150 keV. These formulae take into account or do not the diffuseness correction ( Z²/A\ensuremath Z^2/A term), the charge exchange correction term ( Z^4/3/A^1/3\ensuremath Z^{4/3}/A^{1/3} term), the curvature energy, the Wigner terms and different powers of I = (N - Z)/A . The Coulomb diffuseness correction or the charge exchange correction term play the main role to improve the accuracy of the mass formulae. The different fits lead to a surface energy coefficient of around 17-18MeV. A possible more precise formula for the Coulomb radius is R₀ = 1.2332A^1/3 + 2.8961/A^2/3 - 0.18688A^1/3I\ensuremath R_0 = 1.2332A^{1/3} + 2.8961/A^{2/3} - 0.18688A^{1/3}I fm with s \sigma = 0.052 fm.     

Predictions of nuclear charge radii

In this study,we improve the relations of the charge-radius difference of two isotopes by considering a term that relates to the proton number and the parity of the neutron number.The correction reduces the root-meansquared deviation to 0.0041 fm for 651 nuclei with a neutron number larger than 20,in comparison with experimental data compiled in the CR2013 database.The improved relations are combined with local relations consisting of the charge radii of four neighboring nuclei.These combination...     

New nuclear charge radii database

Several large relational databases (DBs) containing various atomic nucleus parameters and nuclear reaction features were produced at the Centre for Photonuclear Experiments Data (Centr Dannyh Fotoyadernykh Eksperimentov (CDFE)) of the Skobeltsyn Institute of Nuclear Physics, Moscow State University). The sources are numerical data founds maintained by International Nuclear Data Centers Network of the International Atomic Energy Agency (IAEA) and produced by CDFE. The original CDFE product is the electronic “Chart of Quadrupole Nuclear Deformations” which includes ∼2000 sets of data on nuclei quadrupole moments Q and quadrupole deformation parameters β₂ for ∼1500 nuclei. At last time, in the frame of joint research with the Joint Institute for Nuclear Research (JINR) that electronic Chart was supplemented with the data on nuclear mean-root-square (MRS) charge radii (∼900 isotopes of 90 elements (Z = 1–96, N = 0–152)) and therefore transformed into the “Chart of Nucleus Shape and Size Parameters”—complete collection of data under discussion. New Chart allows one to investigate the isotopic and isotonic behavior of nuclei quadrupole moments, parameters of quadrupole deformation and charge radii, and study the R(Z, N) surface structure and R(A) dependence of the fine structure. Original Russian Text ? I.N. Boboshin, V.V. Varlamov, Yu.P. Gangrsky, B.S. Ishkhanov, S.Yu. Komarov, K.P. Marinova, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 6, pp. 857–862.     

关于原子核电荷半径的研究

结合原子核电荷半径实验数据, 对885个中子数N≥8和质子数Z≥8的核电荷半径做了系统的研究. 对于单参数核电荷半径公式, Z^1/3律公式计算的结果优于A^1/3律的结果, 而对于两参数和三参数公式, Z^1/3律和A^1/3律的结果基本相当. 考虑到壳效应及奇偶摆动现象, 在原有的三参数公式基础上提出了加入Casten因子项和δ项的核电荷半径新公式. 利用该公式计算得到的核电荷半径理论值和实验值符合得非常好, 均方根偏差仅为σ=0.0266 fm, 此值比常用的三参数公式的结果下降了近50%, 理论计算值能更好地反映出壳效应及核电荷半径奇偶摆动的变化趋势.     

Barrett moments and rms charge radii

An empirical relation is established between Barrett equivalent radii R _k,α and rms charge radii < r ² >^1/2 based on the results of model-independent and Fermi model analyses of 2p → 1s transitions in muonic atoms. This relation follows simple Z dependence, and can be usefully applied to derive rms radii < r ² >^1/2 or differences δ ^AA ′ < r ² >^1/2 in cases where only R _k,α data or isotope shifts δ ^AA ′ R _k,α are published. The atomic number dependence of the Barrett parameters k(Z) and α(Z) is also given by empirical formulae. It is shown that the Barrett moment can be expanded in a sum of integer moments < r ^m > (m ≥ 2) using an effective exponential parameter α _eff(Z). The moments < r ^m > and isotopic differences δ < r ^m > of the two-parameter Fermi distribution expressed in terms of the parameters c and a are given in the Appendix for m = 1 – 10.     

Nuclear charge radii from optical spectroscopy

The changes of the mean-square nuclear charge radii have been re-evaluated [3] on an equivalent basis, using all available data from optical spectroscopy. The steps of evaluation are discussed and the results are presented in a number of diagrams, showing the course of 〈r ²〉 fromN=20 toN=152 and showing details of δ〈r ²〉     

Nuclear charge radii of molybdenum fission fragments

Radioisotopes of molybdenum have been studied using laser spectroscopy techniques at the IGISOL facility, University of Jyväskylä. Differences in nuclear charge radii have been determined for neutron deficient isotopes ^90,91Mo and neutron rich isotopes ^{102–106,108}Mo (and all stable isotopes). A smooth transition in the mean square charge radii is observed as the neutron number increases with no sudden shape change observed in the region around N=60$N=60$. As N   increases, the nuclear deformation appears to go beyond a maximum and a fall off at N=66$N=66$ is observed. The magnetic moments of the odd isotopes ^91,103,105Mo are also determined.     

New model of kaon regeneration

It is shown that in the standard model of K_S~0 regeneration a system of non-coupled equations of motion is used instead of the coupled ones. A model alternative to the standard one is proposed. A calculation performed by means of the diagram technique agrees with that based on exact solution of the equations of motion.     

Charge radii from lattice relative charge distributions

Electromagnetic charge radii values are extracted from relative charge distribution data for pseudoscalars using lattice QCD techniques. This is done with Wilson fermions and SU(2) color at five values of the hopping parameter.     

带电导体椭球的面电荷密度与主曲率半径的关系

求出了带电导体椭球的面电荷密度与主曲率半径的关系.     

Quark cluster model

The quark-meson hybrid model, in which the quark cluster model for baryon- baryon interactions is supplemented with meson-exchange contributions, is briefly reviewed. Some arguments are given that such a hybrid picture provides us with a simple and efficient way of describing single- and two- baryon systems.     

The charge radii of198Pt-183Pt

The reactions⁵⁸Ni+¹⁰²Pd→¹⁶⁰W and⁵⁸Ni+¹⁰⁶Cd→¹⁶⁴Os were investigated to search for new decay data of neutron deficient nuclei. Excitation energies of the compound nuclei covered a range from 47 to 89 MeV. Velocity separation of the evaporation residues and position time correlations with the a decays of the implanted nuclei were used. The following new decay data were measured:¹⁶²Os (E_α=(6611 ±30) keV, T_1/2=(1.9±0.7) ms);¹⁵⁸W (T_1/2=(0.9±0.3) ms);¹⁵⁸m_W (E=1.88 MeV, E_α=(8280±30) keV, T_1/2=(0.01-1) ms);^155mLu (E_α=(5575±10) keV); β decay of¹⁵⁶Ta (T_1/2 > 10 ms) to the 8⁺ yrast isomer in¹⁵⁶Hf. A cross section of 5μb was measured for the new isotope¹⁵⁶Ta produced in a p3n evaporation channel from¹⁶⁰W at 64 MeV excitation energy.     

Calculations of electric quadrupole moments and charge radii for high-K isomers

Configuration-constrained potential-energy-surface calculations are performed to investigate high-K isomers in ⁹⁷Y, ¹³⁰Ba, ¹⁷⁶Yb, ¹⁷⁷Lu, and ¹⁷⁸Hf that were observed to have increased electric quadrupole moments but decreased charge radii relative to the states on which they are built. Taking into account the effects of deformation change and unpaired protons, our calculations can reproduce the enhancement of electric quadrupole moments for the isomers in ⁹⁷Y, ¹³⁰Ba, ¹⁷⁶Yb, ¹⁷⁷Lu and the K ^π = 8^? isomer in ¹⁷⁸Hf, and can reproduce the reduction of charge radii for the K ^π = 27/2^? isomer in ⁹⁷Y and the K ^π = 16⁺ isomer in ¹⁷⁸Hf.