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1.
D.?R.?Zinatulina Ch.?Brian?on V.?B.?Brudanin R.?V.?Vasilyev K.?Ya.?Gromov V.?G.?Egorov C.?Petitjean V.?I.?Fominykh V.?G.?Chumin M.?V.?Shirchenko I.?A.?Yutlandov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):825-828
The energy and time spectra of γ rays emitted during negative-muon capture in 150Sm were studied. The total muon lifetime in 150Sm was measured. The yields of several radioactive isotopes in this reaction were determined. The partial γ-ray yield upon muon capture by a 150Sm nucleus were measured. 相似文献
2.
E. N. Elekina A. A. Krutov A. P. Martynenko 《Physics of Particles and Nuclei Letters》2011,8(4):331-336
On the basis of quasi-potential approach to the bound state problem in QED we calculate the vacuum polarization, recoil and
structure corrections of orders α5 and α6 to the fine splitting interval ΔE
fs = E(2P
3/2) − E(2P
1/2) in muonic 24He ion. The resulting value ΔE
fs = 146180.68 μeV provides reliable guideline in performing a comparison with the relevant experimental data. 相似文献
3.
Pushpendra P. Singh Manoj Kumar Sharma Unnati Devendra P. Singh Rakesh Kumar K. S. Golda B. P. Singh R. Prasad 《The European Physical Journal A - Hadrons and Nuclei》2007,34(1):29-39
With a view to study complete- and incomplete-fusion components in 159Tb , 169Tm ( 16O , x reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD
Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides; 168m
Lu , 167Lu , 167Yb , 166Tm produced in the
16O$ + $159Tb
system at ≈ 90 MeV, and 179Re , 177Re , 177W , 178Ta and 177Hf produced in the
16O$ + $169Tm
system at ≈ 87 MeV have been measured. The recoil-catcher activation technique followed by off-line γ -spectrometry has been
employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework
of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations.
Different complete- and incomplete-fusion components, which may be attributed to the fusion of 16O and/or 12C and 8Be transfer from the 16O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage
contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion
contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model
code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given
energies. 相似文献
4.
R. Schumacher 《The European Physical Journal A - Hadrons and Nuclei》2008,35(3):299-305
Multiple polarization observables must be measured to access the amplitude structure of pseudoscalar meson photoproduction
off the proton. The hyperon-producing reactions are especially attractive to study, since the weak decays allow straightforward
measurement of the induced and recoil polarization observables. In this paper we emphasize γ + p → K
+ + Λ , discussing recent measurements of Cx, Cz, and P for this reaction. An empirical constraint on the helicity amplitudes is obtained. A simplified model involving spin-flip
and spin-non-flip amplitudes is presented. Finally, a semi-classical model of how the polarization may arise is presented. 相似文献
5.
I. V. Glavanakov P. Grabmayr Yu. F. Krechetov A. N. Tabachenko 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):747-749
Experimental research on positive-pion photoproduction on the oxygen nucleus in the 16O(γ, π+p) reaction at high recoil momenta of the residual nuclear system was performed. The yield for the 16O(γ, π+p) reaction was analyzed using a model that takes Δ-isobar configurations in nuclei ground states into account, together with
the earlier-measured yield of the12C(γ, π+p) reaction. The estimated number of isobars per nucleon N
Δ = 0.012 ± 0.005 was obtained for the 12C nucleus, and 16O N
Δ = 0.018 ± 0.004 was obtained for the 16O nucleus. 相似文献
6.
H. Kettunen T. Enqvist M. Leino K. Eskola P.T. Greenlees K. Helariutta P. Jones R. Julin S. Juutinen H. Kankaanpää H. Koivisto P. Kuusiniemi M. Muikku P. Nieminen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):457-467
The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by
a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of E
α = 6953(3) keV and a half-life T
1/2 = 328(20) ms. Another state with an alpha-decay energy E
α = 7075(4) keV and a half-life T
1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin and parity of 7/2- were deduced. Consequently, the same 7/2- character was assigned to the initial state at 32(7) keV in 195At on the basis of unhindered alpha-decay. The 9/2- state, being the ground state in heavier odd-mass astatine isotopes, was not observed.
Received: 16 September 2002 / Accepted: 19 December 2002 / Published online: 25 March 2003
RID="a"
ID="a"e-mail: heikki.kettunen@phys.jyu.fi
RID="b"
ID="b"Present address: Laboratory of Radiochemistry, P.O. Box 55, FIN-00014, University of Helsinki, Finland.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki, Finland.
Communicated by W. Henning 相似文献
7.
S. B. Dubovichenko 《Physics of Atomic Nuclei》2011,74(3):358-370
Within the potential cluster model where orbital states are classified according to Young diagrams and isospin, astrophysical
S factors are considered for radiative proton capture by 3H and 7Li nuclei at energies of up to 1 and 10 keV, respectively. It is shown that the approach used, which takes into account only
the E1 transition for the p
3H capture process, makes it possible to describe well the most recent experimental data at c.m. energies in the range from
50 keV to 5MeV. In the case of proton capture by 7Li nuclei, an M1 processwas taken into account in addition to the E1 transition, and a general behavior and the magnitude of the experimental S factor could be correctly reproduced owing to this at astrophysical energies, including the region around the resonance at
0.441 MeV (in the laboratory frame). 相似文献
8.
A. A. Krutov A. P. Martynenko 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,62(2):163-175
On the basis of the perturbation theory in the fine structure constant α and the ratio of the electron to muon masses we calculate one-loop vacuum polarisation and electron vertex corrections and
the nuclear structure corrections to the hyperfine splitting of the ground state of the muonic helium atom (μ e
3
2He). We obtain total results for the ground state hyperfine splitting Δ
ν
hfs
= 4166.648 MHz which improves the previous calculation of Lakdawala and Mohr due to new corrections of orders α
5 and α
6. The remaining differences between our theoretical result and experimental value of the hyperfine splitting lie in the range
of theoretical and experimental errors and require the subsequent investigation of higher order corrections. 相似文献
9.
Stanislaw Ciechanowicz Nicolai Popov 《Zeitschrift fur Physik C Particles and Fields》1993,57(4):623-629
Multipole expansion of the partial transition amplitude in the nuclear muon capture with massive lefthanded Dirac neutrino has been derived. The multipole amplitudes for the partial nuclear transitions are given as the explicit functions of the neutrino mass parameter. As an example, the capture rate, the recoil asymmetry and the neutrino polarization are investigated in terms of these multipole amplitudes. The transversal neutrino polarization provides a connection between theT-violation and the neutrino mass: ifT-odd component in the neutrino polarization is observed, then neutrino must be a massive particle. It turns out that in the capture rate and recoil polarization, the effects due to very small neutrino mass can be proportional to the square ratio of the neutrino mass to its momentum, while the neutrino transversal polarization is proportional to this ratio only. Under the recent limits on the muon neutrino mass, the observable effects inthe partial transition may be below the order of ?10?3. 相似文献
10.
S. Kumari S. N. Chatterjee L. K. Jha B. N. Roy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(2):355-363
H+ impact single and He2+ impact single and double electron
capture cross sections of magnesium atoms have been calculated in the
modified binary encounter approximation (BEA). The accurate expressions of
ion impact sDE\sigma _{\Delta {E}} (cross section for energy transfer
DE\Delta E) and Hartree-Fock momentum distributions of the target
electrons have been used throughout the calculations. On the basis of the
present work it is concluded that inner shell captures by H+ and
He2+ ions incident on magnesium atoms contribute partly to single
electron capture and partly to transfer ionization cross sections. The
calculated He2+ impact double electron capture cross sections of
magnesium are in reasonably good agreement with the experimental
observations. This indicates the success of the present theoretical approach
in study of charge transfer cross sections of atoms as indirect mechanisms do
not interfere with double electron capture processes in this case. 相似文献
11.
Nuclear spin dynamics of the 129Xe and 131Xe isotopes in an external magnetic field B 0 is considered. Nuclear spin is pumped by the laser through 87Rb, which transfers the electron spin to the 129Xe and 131Xe nuclei in the spin-exchange interaction. The nuclear spin dynamics is controlled with a transverse magnetic field that causes nuclear magnetic resonance in both 129Xe and 131Xe isotopes. Numerical calculations are performed to find conditions at which the transverse component of the nuclear spin in the established motion is of maximum and the slope angle relative to the vector of the constant magnetic field B 0 is 45°. This regime is taken to be optimal for simulation of practical applications. It is also found that the pump of the nuclear spin of xenon is strongly attenuated when the rubidium polarization vector is turned to the plane perpendicular to the external magnetic field vector B 0. 相似文献
12.
On the basis of quasipotential approach to the bound state problem in QED we calculate the vacuum polarization, relativistic,
recoil, structure corrections of orders α
5 and α
6 to the fine structure interval ΔE
fs = E(2P
3/2) − E(2P
1/2) and to the hyperfine structure of the energy levels 2P
1/2 and 2P
3/2 in muonic 23He ion. The resulting values ΔE
fs = 144 803.15 μeV, Δ$
\tilde E
$
\tilde E
hfs(2P
1/2) = −58 712.90 μeV, Δ$
\tilde E
$
\tilde E
hfs(2P
3/2) = −24 290.69 μeV provide reliable guidelines in performing a comparison with the relevant experimental data. 相似文献
13.
We consider three-loop radiative recoil corrections to hyperfine splitting in muonium due to insertions of the one-loop polarization
operator in the electron factor. The contribution generated by electron polarization insertions is a cubic polynomial in the
large logarithm of the electron—muon mass ratio. The leading logarithm cubed and logarithm squared terms are well known for
some time. We calculate all single-logarithmic and nonlogarithmic radiative recoil corrections of the order α3
(m/M)EF generated by diagrams with the electron and muon polarization insertions. 相似文献
14.
A. Korzenev 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):606-609
New results on the longitudinal inclusive spin asymmetry A
1
d in the range 1 < Q
2 < 100(GeV/c)^2 and 0.004 < x < 0.7 are presented. From these results we derive the spin-dependent structure function g
1
d which we use to evaluate the scale-invariant flavor-singlet axial charge
. The contribution of the measured region is evaluated by a QCD fit of the world data. The data were obtained by the COMPASS
experiment at CERN using a 160GeV polarized muon beam scattered off a large double-cell polarized 6LiD target. The results are in agreement with those from previous experiments and improve considerably the statistical accuracy
in the region x < 0.03. 相似文献
15.
V. V. Afrosimov A. A. Basalaev Yu. G. Morozov M. N. Panov O. V. Smirnov E. A. Tropp 《Technical Physics》2011,56(5):597-604
Time-of-flight mass spectroscopy methods are employed for studying processes occurring during capture of electrons by 3He2+ and Ar6+ multiply charged ions with energy 6z keV (z is the ion charge) from C2H
n
molecules (n = 2, 4, 6) with different multiplicities of C-C bonds. Fragmentation schemes of the molecular ions formed in such processes
are established from analysis of correlations of recording times for all fragment ions. The absolute values of the cross sections
of capture of an electron and capture with ionization are measured, as well as the cross sections of formation of fragment
ions in these processes. The absolute values of total capture cross sections for several electrons are determined. 相似文献
16.
The effect of polarization of the 6Li and 3H clusters on the parameters of states of the 7Li nucleus and on the cross section for the reaction 6Li(n,3H)4He was studied. The 4He + d + n three-cluster configuration was invoked for this purpose, and cluster dynamics was determined within a microscopic model
where the relative motion of the clusters was described in terms of Faddeev amplitudes. The 4He + d + n three-cluster configuration made it possible to consider the 4He + 3H and 6Li + n binary channels, which are dominant in 7Li, and to take simultaneously into account the cluster polarization of 6Li as a two-cluster subsystemin the 4He + d representation and the cluster polarization of 3Has a two-cluster subsystem in the d + n representation. 相似文献
17.
Mass distribution and evaporation residue measurements have been carried out in the reaction 19F + 197Au using the recoil catcher technique followed by off-line γ-ray spectrometry. The random neck rupture model (RNRM) has been
used to compute the variance of the mass distribution ( σ2A) and the average kinetic energy ( ˉ) of the fission fragments for the present system. The results of model calculations have
been found to be in good agreement with the experimental observations. Measured evaporation residue cross-sections have been
compared with the statistical model calculations. 相似文献
18.
Differential cross sections and polarization observables for the elastic and inelastic scattering of 800-MeV protons on 16O and 20Ne nuclei are calculated on the basis of the theory of multiple diffractive scattering and the α-cluster model involving dispersion. The single-particle nucleon-density distributions obtained within the α-cluster model involving dispersion are used in the calculations. The differential cross sections and polarization calculated for elastic and inelastic p16O and p20Ne scattering are compatible with available experimental data. The spin-rotation functions calculated for elastic p16O and p20Ne scattering within the independent-nucleon model differ qualitatively from their counterparts calculated within the α-cluster model involving dispersion. 相似文献
19.
B. V. Zhuravlev A. A. Lychagin N. N. Titarenko V. G. Demenkov V. I. Trykova 《Physics of Atomic Nuclei》2011,74(3):335-340
The spectra of neutrons from the (p, n) reactions on 47Ti, 48Ti, 49Ti, 53Cr, and 54Cr nuclei were measured in the proton-energy range 7–11 MeV. The measurements were performed with the aid of a fast-neutron
spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and
Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used,
low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured
data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations
were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model
of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level
density. The nuclear level densities for 47V, 48V, 49V, 53Mn, and 54Mn were determined along with their energy dependences and model parameters. The results are discussed together with available
experimental data and recommendations of model systematics. 相似文献
20.
V. K. Kalevich A. Yu. Shiryaev E. L. Ivchenko A. Yu. Egorov L. Lombez D. Lagarde X. Marie T. Amand 《JETP Letters》2007,85(3):174-178
Conduction-electron spin polarization dynamics achieved by pulsed optical pumping at room temperature in GaAs1−x
N
x
alloys with a small nitrogen content (x = 2.1, 2.7, and 3.4%) is studied both experimentally and theoretically. It is found that the photoluminescence circular polarization
determined by the mean spin of free electrons reaches 40–45% and this giant value persists within 2 ns. Simultaneously, the
total free-electron spin decays rapidly with the characteristic time ≈ 150 ps. The results are explained by spin-dependent
capture of free conduction electrons on deep paramagnetic centers resulting in the dynamical polarization of bound electrons.
A nonlinear theory of spin dynamics in the coupled system of spin-polarized free and localized carriers has been developed
which describes the experimental dependencies, in particular, the electron spin quantum beats observed in a transverse magnetic
field.
The text was submitted by the authors in English. 相似文献