Charge Radii and Magnetic Polarizabilities of the Rho and K* Mesons in QCD String Theory

The effective action for light mesons in the external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The approximation of the Nambu-Goto straight-line string is used to simplify the problem. The Coulomb-like short-range contribution which goes from one-gluon exchange is also neglected. We do not take into account spin-orbital and spin-spin interactions of quarks and observe the $\rho$ and $K^*$ mesons. The wave function of the meson ground state is the Airy function. Using the virial theorem we estimate the mean charge radii of mesons in terms of the string tension and the Airy function zero. On the basis of the perturbative theory, in the small external magnetic field we find the diamagnetic polarizabilities of $\rho$ and $K^*$ mesons: $\beta_\rho =-0.8\times 10^{-4} {fm}^3$, $\beta_{K^*}=-0.57\times 10^{-4} {fm}^3$Comment: 22 pages, no figures, in LaTeX 2.09, typos correcte

beta-decay study of Cu-77

A beta-decay study of Cu-77 has been performed at the ISOLDE mass separator with the aim to deduce its beta-decay properties and to obtain spectroscopic information on Zn-77. Neutron-rich copper isotopes were produced by means of proton- or neutron-induced fission reactions on U-238. After the production, Cu-77 was selectively laser ionized, mass separated and sent to different detection systems where beta-gamma and beta-n coincidence data were collected. We report on the deduced half-live, decay scheme, and possible spin assignment of 77Cu

Magnetic moments of 68^{68}Cug,m^{g,m} and 70^{70}Cug,m1,m2^{g,m_{1},m_{2}} nuclei measured by in-source laser spectroscopy

We have obtained information on the atomic hyperfine splitting and, hence, on magnetic moments in neutron rich $^{68, 70}$Cu isotopes by scanning the frequency of the narrow-band laser of the first excitation step in the resonance ionization laser ion source. The deduced magnetic moments are $\mu( ^{68}$Cu$^{g}$, I$^{\pi}$ = 1$^+$) = +2.48(2)(7)$\mu_{N}$ ; $\mu(^{68}$Cu$^{m}$, I$^{\pi}$=6$^{-}$) = +1.24(4)(6)$\mu_{N}$ and $\mu(^{70}$Cu$^{m_{2}}$, I$^{\pi}$=1$^{+}$) = +1.86(4)(6)$\mu_{N}$ ; $\mu(^{70}$Cu$^{g}$, I$^{\pi}$=6$^{-}$) = +1.50(7)(8)$\mu_{N}$. The results of the scans analysis point out on existence of a new isomer in $^{70}$Cu$^{m_{1}}$. It's deduced magnetic moment is (-)3.50(7)(11)$\mu_{N}$ that is in a good agreement with I$^{\pi}$=3$^{-}$ assignment. The method of in-source atomic spectroscopy, as well as the analysis of the obtained data, is described. The results are discussed in terms of single-particle configurations coupled to the $^{68}$Ni core

АНАЛИЗ ПОВЕДЕНИЯ ТРЕХСЛОЙНОЙ ГОФРИРОВАННОЙ КОНСТРУКЦИИ ПРИ ЛИНЕЙНОМ ЗАКОНЕ ПОДАЧИ ДАВЛЕНИЯ

There was considered regime of forming for sandwich construction from titanium alloy that represents corrugated filling, inserted between two shell plates, by means of linear law of neutral gas supply. This gas entered in the area between filling and shells. There was offered simple model of process, based on the use of torque-free shell theory. There was offered numerical procedure of the main parameters of examined process. There was offered example of special calculation for titanium alloy VT6 (Ti–6Al–4V). The results of calculations on approximate formulae are correspond to numerical solution of boundary problem of recovery creep theory, obtained by means of software ANSYS.Рассмотрен режим деформирования трехслойной конструкции из титанового сплава, представляющей собой гофрированный наполнитель, помещенный между двумя листами обшивки, при линейном законе подачи инертного газа, поступающего в область между наполнителем и обшивками. Представлена упрощенная модель процесса, основанная на использовании безмоментной теории оболочек. Предложены алгоритмы расчета основных параметров рассматриваемого процесса. Приведен пример конкретного расчета для титанового сплава ВТ6 (Ti–6Al–4V). Результаты расчетов по приближенным формулам сопоставлены с численным решением краевой задачи теории ползучести, полученным в среде программного комплекса ANSYS

МЕТОДЫ РАСЧЕТА ПРОДОЛЖИТЕЛЬНОСТИ ПРОЦЕССА СВЕРХПЛАСТИЧЕСКОЙ ФОРМОВКИ КРУГЛОЙ МЕМБРАНЫ

The process of superplastic forming of a circular membrane under constant pressure is analyzed. The analytical process model is built based on principal assumptions of the thin shell theory, and two simplified approaches known from the literature and based on the hypothesis on the uniform thickness of a shell along its profile, and the uniform stretching of a meridian passing the dome apex. The methods of calculating the duration of superplastic forming of a circular membrane are considered. The finite element modeling of the process considered is made using the educational version of ANSYS software. The paper considers two boundary value problems stated in terms of superplasticity mechanics – the theory of creep and the theory of viscoplasticity. The results of analytical formula calculations are compared with the solutions of boundary value problems in terms of the creep and viscoplasticity theories obtained in the ANSYS software environment. The material constant values are determined from the results of uniaxial tests and test forming of Ti–6Al–4V titanium alloy. It is shown that test forming used to identify the material model provides much more appropriate results with the evaluation error reduced from ~20 % (when identifying the model based on the results of standard uniaxial mechanical tests) to ~3 %.Исследован режим сверхпластической формовки круглой мембраны при постоянном давлении. Математическая модель технологического процесса построена в рамках основных предположений безмоментной теории оболочек, а также двух известных из литературы упрощенных подходов, основанных на гипотезе о равнотолщинности оболочки по ее профилю и равнорастянутости меридиана, проходящего через полюс купола. Проанализированы методы расчета продолжительности процесса сверхпластической формовки круглой мембраны. Проведено конечно-элементное моделирование рассматриваемого процесса с использованием учебной версии программного комплекса ANSYS 10ED. В данной работе рассмотрены два варианта постановки краевой задачи механики сверхпластичности – теории ползучести и вязкопластичности. Результаты вычислений по аналитическим формулам сопоставлены с решениями краевых задач теории ползучести и вязкопластичности, полученными в среде программного комплекса ANSYS. Значения материальных постоянных были определены по данным одноосных испытаний и тестовых формовок титанового сплава ВТ6 (Ti–6Al–4V). Показано, что в том случае, если для идентификации модели материала используются тестовые формовки, результаты расчетов оказываются намного более корректными, а погрешность оценки снижается с уровня ~20 % (при идентификации модели по результатам стандартных одноосных механических испытаний) до ~3 %

On-line yields obtained with the ISOLDE RILIS

The ISOLDE resonance ionization laser ion source (RILIS) allows to ionize efficiently and selectively many metallic elements. In recent yield surveys and on-line experiments with the ISOLDE RILIS we observed $^{23-34}$Mg , $^{26-34}\!$Al , $^{98-132}$Cd , $^{149}$Tb , $^{155-177}\!$Yb , $^{179-200}$Tl , $^{183-215}$Pb and $^{188-218}$Bi. The obtained yields are presented together with measured release parameters which allow to extrapolate the release efficiency towards more exotic (short-lived) nuclides of the same elements

Forward K+ production in subthreshold pA collisions at 1.0 GeV

K+ meson production in pA (A = C, Cu, Au) collisions has been studied using the ANKE spectrometer at an internal target position of the COSY-Juelich accelerator. The complete momentum spectrum of kaons emitted at forward angles, theta < 12 degrees, has been measured for a beam energy of T(p)=1.0 GeV, far below the free NN threshold of 1.58 GeV. The spectrum does not follow a thermal distribution at low kaon momenta and the larger momenta reflect a high degree of collectivity in the target nucleus.Comment: 4 pages, 3 figure

Measurements of 12C(&#8594;γ,pp) photon asymmetries for Eγ= 200–450 MeV

The 12C (&#8594;γ ,pp) reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry Σ has been measured over a wider Eγ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the difference in azimuthal angles of the two ejected protons increased the magnitude of the observed asymmetries. At low missing energies the Σ data exhibit a strong angular dependence, similar to deuteron photodisintegration

REX-ISOLDE: post-accelerated radioactive BEAMS at CERN-ISOLDE

The ISOLDE RIB-facility at CERN has today been producing a vast range of radioactive beams since more than 30 years. The low-energy beams of ISOLDE will be complemented by a post-accelerator, REX-ISOLDE, currently being assembled. In order to convert the pseudo-DC, singly-charged beam from the ISOLDE mass separators into a cooled and bunched beam at higher charge states a novel scheme of trapping, cooling and charge-state breeding has been devised, using a linear Penning trap and an Electron Beam Ion Source (EBIS). This allows for subsequent acceleration by a short, cost-effective LINAC consisting of an RFQ, an IH-structure and three seven-gap resonators, reaching 0.8 - 2.2 MeV/u. The installation of REX-ISOLDE is well underway and the first post-accelerated radioactive beams are expected to be obtained during late 2000