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1.
A. V. Klinskikh S. Brianson V. B. Brudanin V. G. Egorov C. Petitjean M. V. Shirchenko 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(6):735-736
The time and energy spectra of γ rays, accompanying negative muon capture in a 40Ar target, have been measured using Ge detectors. The results of measuring the muon lifetime in 40Ar and yields of different Cl and S isotopes at μ capture are reported. 相似文献
2.
The problem of inclusive muon capture in nuclei is studied by calculating the capture rate in asymmetric infinite nuclear matter and using the local density approximation to evaluate the capture rates in nuclei. It is shown that the method is rather reliable and allows one to improve on approximations used in the past. The need for a strong nuclear renormalization is shown, reducing the capture rates by about a factor two in medium and heavy nuclei. By using standard effective interactions in the spin-isospin channel one can account for this renormalization and one finds a remarkable overall agreement with the measured capture rates for a large list of nuclei through the periodic table. 相似文献
3.
C. Boekema 《Hyperfine Interactions》1984,17(1-4):305-320
Muon spin rotation studies on magnetic oxides among which-Fe2O3 and Fe3O4 have shown that at temperatures below approximately 500 K the muons form a muon-oxygen bond, analogous to a hydrogen bond. Generally, the muon hyperfine interactions in magnetic oxides can be explained in terms of supertransfer (hyperfine) and dipole fields. Supertransfer fields result from covalent bonding effects. For the rare earth (R) orthoferrite series (RFeO3) comparison is made with Mössbauer results on covalency effects in hyperfine interactions. Suggestions for next stages of experimentation in solid state research in oxides bySR are mentioned. 相似文献
4.
E. Kolbe K. Langanke K. Riisager 《The European Physical Journal A - Hadrons and Nuclei》2001,11(1):39-45
Future facilities will allow the exploration of extremely neutron-rich nuclei far from the valley of stability. It is discussed
that the strong-neutron excess results in changes in the collective excitations of such nuclei compared to conventional stable
nuclei. We propose muon capture as an experimental tool to explore such changes. We will quantify our discussion by the calculation
of the total and differential muon capture rates on selected calcium isotopes between 40Ca and 60Ca. Our calculations are based on the random phase approximation and agree nicely with the measured rates for 40Ca and 44Ca.
Received: 6 April 2001 / Accepted: 14 May 2001 相似文献
5.
F. Gray 《The European physical journal. Special topics》2008,162(1):231-237
By measuring the lifetime of the negative muon in pure protium (1H), the MuCap experiment determines the rate of muon capture on the proton, from which the proton’s pseudoscalar coupling
g
p
may be inferred. A precision of 15% for g
p
has been published; this is a step along the way to a goal of 7%. This coupling can be calculated precisely from heavy baryon
chiral perturbation theory and therefore permits a test of QCD’s chiral symmetry. Meanwhile, the MuSun experiment is in its
final design stage; it will measure the rate of muon capture on the deuteron using a similar technique. This process can be
related through pionless effective field theory and chiral perturbation theory to other two-nucleon reactions of astrophysical
interest, including proton-proton fusion and deuteron breakup.
for the MuCap [1] and MuSun [2] Collaborations 相似文献
6.
The transition rates for muon capture in deuterium are calculated using the Reid soft-core deuteron, and 1S0 and neutron-neutron wave functions. The validity of the closure approximation and of the Omnés-Muskhelishvili method is studied. The off-shell effects admissible in a class of phase-shift-equivalent potentials by present experimental data are evaluated. 相似文献
7.
J. G. Congleton 《Nuclear Physics A》1994,570(3-4):511-520
The hypertine effect for muon capture by 3He is calculated in a modified closure approximation as a function of gp, the nucleon pseudoscalar form factor. It is found to be very sensitive to gp. 相似文献
8.
D. R. Zinatulina K. Ya. Gromov V. B. Brudanin Ch. Brianćon 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》2008,72(6):737-743
Energy and time spectra of γ rays following nuclear capture of negative muons in natural Se and Cd and isotopically enriched 76Se and 106Cd targets have been measured with HPGe detectors. Total muon lifetimes in Se and Cd isotopes and partial μ capture rates to excited levels of 76As and 106Ag are obtained. These results are necessary for calculation of nuclear matrix elements of the 2β decay of 76Ge and 106Cd respectively. 相似文献
9.
The slowing down and capture of negative muons in solids is discussed on the basis of classical equations of motion where the energy dissipation is described in terms of frictional forces. Transport equations determining the energy distribution of the muons in the target are formulated and solved for various models. Using a statistical model of the atom it is shown that the muons are captured typically at energies of a few tens of electron volts, that the angular momentum distribution of the muons at capture is almost statistical, and that this distribution is not expected to be qualitatively changed by the subsequent cascade to the tightly bound orbits. In mixtures of atoms with atomic numbers Z1 and Z2 the capture ratio is to a good approximation proportional to the atomic concentration and, in the statistical model, proportional to . Calculations are also performed with more accurate atomic models, and it is shown that capture ratios as well as angular momentum distributions are influenced by the ionicity of the atomic bonds and the atomic shell structure. No systematic study of these effects has been made but the few results obtained seem to be in reasonable agreement with experiments. 相似文献
10.
We calculate total and differential muon capture rates on nickel and tin isotopes ranging from the proton dripline to the neutron dripline. The total rates decrease as the neutron number increases due to the combined effect of gradual blocking of available final-state neutron levels and of decreased phase space. The ordering of single-particle levels determines when blocking becomes important. We show that the total capture rates thereby are sensitive to the evolution of nuclear structure along an isotope chain.Received: 28 January 2003, Revised: 7 March 2003, Published online: 4 June 2003PACS:
24.30.Cz Giant resonances - 23.40.-s Beta decay; double beta decay; electron and muon capture - 23.40.Hc Relation with nuclear matrix elements and nuclear structure 相似文献
11.
The partial capture rates for the process,μ
− +16O (g·s) →16N (2−, 1−, 0−, 3−) +v
μ
have been calculated using the particle-hole wavefunctions obtained using self-consistent procedure. In deriving these wavefunctions,
the effectiveN-N interaction has been constructed from the bare Hamada-Johnston interaction. The terms in the muon capture Hamiltonian that
depend on the momentum of the capturing proton have been included and their importance in 0+ → 0− transition is exhibited. The agreement with the available experimental data is good. The need to incorporate meson exchange
effects in 0+ → 0− transition is pointed out. 相似文献
12.
13.
V. V. Filchenkov 《Physics of Particles and Nuclei》2016,47(4):591-626
Results of theoretical and experimental research on capture of negative muons in hydrogen are reported with an emphasis on the accompanying phenomenon of muon catalysis in hydrogen and subtleties of the experimental method. A conclusion is drawn that precise determination of the capture rate is important for refining the standard model. 相似文献
14.
P. Kammel 《Few-Body Systems》2008,44(1-4):333-336
We survey a new generation of high precision experiments on muon capture in hydrogen and on the positive muon lifetime, performed at the Paul Scherrer Institute (PSI). First results and plans for the future are presented. 相似文献
15.
《Nuclear Physics A》1987,475(4):630-641
Using the lifetime technique, atomic capture ratios of negative muons have been measured in 41 oxides. The results, though a little different from the earlier TRIUMF findings, are consistent with the mesic X-ray measurements. It has been noticed that the atomic capture ratios have an approximately linear dependence on density, whereas the Z-dependence is periodic. 相似文献
16.
We present a new calculation of the capture rates, polarizations and asymmetry parameters of the final nucleus in the capture of muons by any nucleus in the non-breakup channel. We treat nuclei as elementary particles and give explicitly the transition amplitude for any spin configuration. We apply our formulae to hydrogen and 3He, obtaining agreement with the experimental data. 相似文献
17.
Total lifetime distribution analysis was employed to obtain fluorescence lifetime profiles of the intrinsic fluorescence ofPseudomonas fluorescens, Escherichia coli, Bacillus subtilis, andStaphylococcus epidermidis. The lifetimes were measured using a multiharmonic Fourier transform phase-modulation fluorometer which can simultaneously
measure the phase shift and demodulation at many modulation frequencies. The 364-nm line from an argon-ion laser and the 325-
and 442-nm lines from a helium-cadmium laser were used for sample excitation. Broad emission windows were used to capture
as much of the bacterial emission as possible for the lifetime measurements. The maximum entropy method was used to recover
lifetime profiles from the multifrequency phasemodulation data. At all three excitation wavelengths, the bacteria exhibited
three lifetime components, in the ranges of 0.5-1, 2–3, and 4–8 ns. Using 325-nm excitation, a fourth component, in the range
of 9–14 ns, was recovered in all of the bacteria; using 364-nm excitation, the fourth component was resolved only in the two
Gram-negative bacteria (P. fluorescens andE. coli). Excitation at 364 nm provided the most reproducible lifetime profiles and showed some differences among the four bacteria. 相似文献
18.
Muon capture and radiative pion capture reactions on 16O have been analysed with the aim to extract more information on the importance of higher components of the A = 16 nuclear ground and excited states. Good agreement with the experimental data for both reactions may be achieved if at least 2p2h components of the nuclear wave functions are taken into account. The positive parity excited states in 16N are shown to contribute 43 % to the radiative π− capture but only ≈ 10 % to the muon capture rate. 相似文献
19.
V. Egorov V. Brudanin K. Gromov A. Klinskih M. Shirchenko Ts. Vylov I. Yutlandov D. Zinatulina Ch. Briançon C. Petitjean O. Naviliat-Cuncic 《Czechoslovak Journal of Physics》2006,56(5):453-457
Gamma-rays following nuclear capture of negative muons in enriched 48Ti, 76Se, 106Cd, as well as natural Se and Cd targets were measured. Time evolution of several gamma-lines allowed to deduce the total
μ-capture rates in Ti, Se and Cd isotopes, which are compared to the Primakoff estimate. The data on the partial μ-capture rates will be used for more precise calculation of the 2β-NMEs of 48Ca, 76Se and 106Cd.
Presented by V. Egorov at the Workshop on calculation of double-beta-decay matrix elements (MEDEX’05), Corfu, Greece, September
26–29, 2005.
Partly supported by the Russian Foundation for Basic Research (grant 06-02-16587). 相似文献