Mostrando recursos 1 - 20 de 422

  1. Magnetic Hexadecapole γ Transitions and Neutrino-Nuclear Responses in Medium-Heavy Nuclei

    Lotta Jokiniemi; Jouni Suhonen; Hiroyasu Ejiri
    Neutrino-nuclear responses in the form of squares of nuclear matrix elements, NMEs, are crucial for studies of neutrino-induced processes in nuclei. In this work we investigate magnetic hexadecapole (M4) NMEs in medium-heavy nuclei. The experimentally derived NMEs, MEXP(M4), deduced from observed M4 γ transition half-lives are compared with the single-quasiparticle (QP) NMEs, MQP(M4), and the microscopic quasiparticle-phonon model (MQPM) NMEs MMQPM(M4). The experimentally derived M4 NMEs are found to be reduced by a coefficient k≈0.29 with respect to MQP(M4) and by k≈0.33 with respect to MMQPM(M4). The M4 NMEs are reduced a little by the quasiparticle-phonon correlations of the MQPM...

  2. An Optimized Gamma-ray Densitometry Tool for Oil Products Determination

    Amirmohammad Beigzadeh; Hossein Afarideh; Eskandar Asadi Amirabadi; Zahra Soltani; Gholam Reza Etaati
    Gamma-ray densitometry or nucleonic gauges have been widely used in industries to improve the quality of products, optimize processes and save energy and materials. Compared with common time-consuming and expensive chemical analyses, the proposed method is relatively fast and more reliable. Density measurement is normally based on the absorption of gamma radiation as it passes through the process material. The absorption which is proportional to the changes in material density indicates product density as the measuring path is held constant. In this study, a number of Monte Carlo simulations have been performed using the MCNP-4C code to optimize the arrangement...

  3. Mesonic Decay of Charm Hypernuclei Λc+

    Ghosh Sabyasachi; Fontoura Carlos E.; Krein Gastão
    Λc+ hypernuclei are expected to have binding energies and other properties similar to those of strange hypernuclei in view of the similarity between the quark structures of the strange and charmed hyperons, namely Λ(uds) and Λc+(udc). One striking difference however occurs in their mesonic decays, as there is almost no Pauli blocking in the nucleonic decay of a charm hypernucleus because the final-state nucleons leave the nucleus at high energies. The nuclear medium nevertheless affects the mesonic decays of charm hypernucleus because the nuclear mean fields modify the masses of the charm hyperon. In the present communication we present results...

  4. General Description of Fission Observables: GEF Model Code

    Schmidt, Karl-Heinz; Jurado, Beatriz; Amouroux, Charlotte; Schmitt, C.
    The GEF (" GEneral description of Fission observables ") model code is documented. It describes the observables for spontaneous fission, neutron-induced fission and, more generally, for fission of a compound nucleus from any other entrance channel, with given excitation energy and angular momentum. The GEF model is applicable for a wide range of isotopes from Z = 80 to Z = 112 and beyond, up to excitation energies of about 100 MeV. The results of the GEF model are compared with fission barriers, fission probabilities, fission-fragment mass-and nuclide distributions, isomeric ratios, total kinetic energies, and prompt-neutron and prompt-gamma yields and...

  5. Microwold 20. “Spontaneous ” Nuclear Disintegration

    N. N. Leonov
    “Spontaneous ” nuclear disintegration results from increase in the density of ether in the contemporary Universe. Red shift is indicative of increase in the density of ether in the peripheral regions of the Universe. The observable phenomenon of “spontaneous ” nuclear disintegration provides experimental evidence of the fact that increase in the density of ether in the contemporary Universe takes place in the entire Universe rather in its peripheral layers. It is common knowledge that atomic nuclei of a number of chemical elements are capable of being disintegrated by external influence into various fragments from single nucleons to different nucleonic...

  6. Real time processing of neutron monitor data using the edge editor algorithm

    Mavromichalaki Helen; Paschalis Pavlos
    The nucleonic component of the secondary cosmic rays is measured by the worldwide network of neutron monitors (NMs). In most cases, a NM station publishes the measured data in a real time basis in order to be available for instant use from the scientific community. The space weather centers and the online applications such as the ground level enhancement (GLE) alert make use of the online data and are highly dependent on their quality. However, the primary data in some cases are distorted due to unpredictable instrument variations. For this reason, the real time primary data processing of the measured...

  7. Dense nucleonic matter and the renormalization group

    Drews Matthias; Hell Thomas; Klein Bertram; Weise Wolfram
    Fluctuations are included in a chiral nucleon-meson model within the framework of the functional renormalization group. The model, with parameters fitted to reproduce the nuclear liquid-gas phase transition, is used to study the phase diagram of QCD. We find good agreement with results from chiral effective field theory. Moreover, the results show a separation of the chemical freeze-out line and chiral symmetry restoration at large baryon chemical potentials.

  8. The detection of solar proton produced 14CO

    P. Jöckel; C. A. M. Brenninkmeijer; M. G. Lawrence; P. Siegmund
    Major solar eruptions (coronal mass ejections) are accompanied by massive ejections of protons. When these charged particles head for the Earth through the interplanetary magnetic field with high flux and energy, a solar proton event (SPE) is recorded. Strong SPEs, in which energetic protons penetrate the atmosphere in large numbers are rare, but do have chemical effects (Crutzen, 1975; Jackman et al., 1990, 2001).  They also have nucleonic effects by which they can almost instantaneously increase the atmospheric production of radio-nuclides, including 14C (radiocarbon), but this has never been demonstrated. We show, using satellite observations and modeling, that the 2nd...

  9. From crystalline to exotic arrangements of matter in neutron star crusts

    Figerou S.; Sébille F.; de la Mota V.; Eudes Ph.
    We investigate the occurrence of exotic structures in the outermost layers of neutron stars within the framework of a microscopic model describing the nucleonic dynamics through a time-dependent mean field approach at around zero temperature. In this model starting from an initial crystalline lattice of nuclei at subnuclear densities the system evolves and self-organizes in various low-lying energy structures without assumption of final shapes. These structures are studied in terms of a density phase diagram. We investigate their sensitivity to the isotopic composition and to the symmetries of the lattice.

  10. Atmospheric electric field effects of cosmic rays detected in Mexico City

    J. F. Valdés-Galicia; L. X. González
    We studied the possible effects of atmospheric electric fields, generated in thunderstorms, on the cosmic ray intensity detected at the Earth’s surface by investigating the variations of the counting rates of the cosmic-ray nucleonic component, obtained from the neutron monitor installed in Mexico City, for thunderstorms during 1996 and 1997. These were years of minimum solar activity. We compare our experimental results with the general theory of cosmic ray meteorological effects by Dorman (1995).The observed intensity variation is about 0.2%. According to Dorman (1995), the effect should be between 0.27% and 0.81% on the counting rate of the neutron monitor...

  11. Electroweak reactions with light nuclei

    Bacca S.
    The investigation of light nuclei with ab-initio methods provides an optimal setting to probe our knowledge on nuclear forces, because the few-nucleon problem can be solved accurately. Nucleons interact not only in pairs but also via many-body forces. Theoretical efforts need to be taken towards the identification of nuclear observables sensitive to the less known many-nucleon forces. Electromagnetic reactions can potentially provide useful information on this. We present results on photo-absorption and electron scattering off light nuclei, emphasizing the role of three-body forces and the comparison with experimental data. On the other hand, reactions induced by weak probes, like neutrino...

  12. Nuclear stopping for heavy-ion induced reactions in the Fermi energy range : from 1-Body to 2-Body dissipation

    Lopez O.; Lehaut G.; Durand D.; Aouadi M.
    We study the stopping in heavy-ion induced reactions around the Fermi energy in central collisions. The stopping is minimal around the Fermi energy and corresponds to the crossover between the Mean-Field and the nucleonic regimes. This is attributed to the change in the energy dissipation going from 1-body (Mean-Field) to 2-body (nucleonnucleon collisions) dissipation. For this latter, a connection to in-medium transport properties of nuclear matter is proposed and comprehensive values of the nucleon mean free path and nucleon-nucleon cross section are extracted.

  13. Nuclear stopping for heavy-ion induced reactions in the Fermi energy range : from 1-Body to 2-Body dissipation

    Lopez O.; Lehaut G.; Durand D.; Aouadi M.
    We study the stopping in heavy-ion induced reactions around the Fermi energy in central collisions. The stopping is minimal around the Fermi energy and corresponds to the crossover between the Mean-Field and the nucleonic regimes. This is attributed to the change in the energy dissipation going from 1-body (Mean-Field) to 2-body (nucleonnucleon collisions) dissipation. For this latter, a connection to in-medium transport properties of nuclear matter is proposed and comprehensive values of the nucleon mean free path and nucleon-nucleon cross section are extracted.

  14. CONTROL OF ACTIVATORS OF SHARP INTESTINAL INFECTIONS OVER BASIS PCR-RT Контроль возбудителей острых кишечных инфекций на основе ПЦР-РТ

    Brovkina A. N.
    The "multiplex" PCR technique in a combination with automatic extraction of nucleonic acids allows to carry out the control of activators of sharp intestinal infections of the bacterial and virus nature over objects of an environment with high speed, specificity and sensitivity

  15. CONTROL OF ACTIVATORS OF SHARP INTESTINAL INFECTIONS OVER BASIS PCR-RT Контроль возбудителей острых кишечных инфекций на основе ПЦР-РТ

    Brovkina A. N.
    The "multiplex" PCR technique in a combination with automatic extraction of nucleonic acids allows to carry out the control of activators of sharp intestinal infections of the bacterial and virus nature over objects of an environment with high speed, specificity and sensitivity

  16. Neutron spectroscopic factors of 55Ni hole-states from (p,d) transfer reactions

    A. Sanetullaev; M.B. Tsang; W.G. Lynch; Jenny Lee; D. Bazin; K.P. Chan; D. Coupland; V. Henzl; D. Henzlova; M. Kilburn; A.M. Rogers; Z.Y. Sun; M. Youngs; R.J. Charity; L.G. Sobotka; M. Famiano; S. Hudan; D. Shapira; W.A. Peters; C. Barbieri; M. Hjorth-Jensen; M. Horoi; T. Otsuka; T. Suzuki; Y. Utsuno
    Spectroscopic information has been extracted on the hole-states of 55Ni, the least known of the quartet of nuclei (55Ni, 57Ni, 55Co and 57Cu), one nucleon away from 56Ni, the N=Z=28 double magic nucleus. Using the H1(Ni56,d)Ni55 transfer reaction in inverse kinematics, neutron spectroscopic factors, spins and parities have been extracted for the f7/2, p3/2 and the s1/2 hole-states of 55Ni. These new data provide a benchmark for large basis calculations that include nucleonic orbits in both the sd and pf shells. State of the art calculations have been performed to describe the excitation energies and spectroscopic factors of the s1/2...

  17. Neutron–proton effective mass splitting in neutron-rich matter at normal density from analyzing nucleon–nucleus scattering data within an isospin dependent optical model

    Xiao-Hua Li; Wen-Jun Guo; Bao-An Li; Lie-Wen Chen; Farrukh J. Fattoyev; William G. Newton
    The neutron–proton effective mass splitting in asymmetric nucleonic matter of isospin asymmetry δ and normal density is found to be mn−p⁎≡(mn⁎−mp⁎)/m=(0.41±0.15)δ from analyzing globally 1088 sets of reaction and angular differential cross sections of proton elastic scattering on 130 targets with beam energies from 0.783 MeV to 200 MeV, and 1161 sets of data of neutron elastic scattering on 104 targets with beam energies from 0.05 MeV to 200 MeV within an isospin dependent non-relativistic optical potential model. It sets a useful reference for testing model predictions on the momentum dependence of the nucleon isovector potential necessary for understanding novel...

  18. Quantum Physics Status

    N. N. Leonov
    Quantum physics is an approximate theory of the microworld. Its application is limited due to refusal to consider ether resistance to motion of microobjects and negligence of magnetic interactions among the same. Quantum physics is considered to be an unprecedentedly revolutionary and extremely effective means of the material world perception. It seems to be confirmed by the practical results it achieved. But the year 1979 saw publication [l] of findings meaning that nuclei of all chemical elements have quasicrystalline structures. In other words the nucleonic systems of such nuclei feature stable statically equilibrium configurations. The findings imply that ħ=0 in...

  19. Exclusive Study of Deuteron Electrodisintegration near Threshold

    G. D. Cates; R. Lindgren; N. Liyanage; V. Nelyubin; B. E. Norum; K. Paschke; L. C. Smith; K. Wang; X. Zheng; M. Schwamb; B. Sawatzky; R. Igarashi; R. Pywell; G. Rosner; D. Watt; X. Jiang; J. Calarco; Y. Jiang; H. Lu; J. Shen; X. Yan; Y. Ye; Z. Yin; P. Zhu; J. P. Chen; O. Hansen; D. W. Higinbotham; J. Lerose
    Elastic electron scattering from the deuteron and near-threshold electro-disintegration have long provided benchmarks against which models of the nucleon-nucleon interaction are evaluated. Recent measurements of T20 in elastic scattering have tightened the constraints but still leave room for ambi-guity. We propose to make similar improvements in the constraints imposed by electrodisintegration with an exclusive study of the reaction d(~e; e0p)n at Q2 = 12 fm2 and Enp = 2, 4, 6, 8 MeV. Under these kinematics, non-nucleonic as well as nucleonic degrees of freedom and relativistic eects are expected to play major roles. The experiment will be conducted in Hall...

  20. Microwold 20. “Spontaneous ” Nuclear Disintegration

    N. N. Leonov
    “Spontaneous ” nuclear disintegration results from increase in the density of ether in the contemporary Universe. Red shift is indicative of increase in the density of ether in the peripheral regions of the Universe. The observable phenomenon of “spontaneous ” nuclear disintegration provides experimental evidence of the fact that increase in the density of ether in the contemporary Universe takes place in the entire Universe rather in its peripheral layers. It is common knowledge that atomic nuclei of a number of chemical elements are capable of being disintegrated by external influence into various fragments from single nucleons to different nucleonic...

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