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1.
Andrzej Adamczak 《Hyperfine Interactions》2001,138(1-4):343-350
Resonant formation of the muonic molecule ddμ in dμ atom scattering in condensed deuterium is considered. In particular, ddμ formation in D2 solid targets containing different ortho-D2 concentration is discussed, and the respective time spectra of the dd fusion products are shown. The results of the first calculation of the resonant ddμ formation rate in liquid deuterium are presented. At large momentum transfers the ddμ formation rate takes the Doppler form, similar to that obtained for a dilute gas target. A condition of validity of this
approximation is also discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
V. R. Bom J. N. Bradbury D. L. Demin C. W. E. van Eijk V. V. Filchenkov N. N. Grafov V. G. Grebinnik K. I. Gritsaj A. D. Konin A. V. Kuryakin V. A. Nazarov V. V. Perevozchikov A. I. Rudenko S. M. Sadetsky Yu. A. Vinogradov A. A. Yukhimchuk S. A. Yukhimchuk V. G. Zinov S. V. Zlatoustovskii 《Hyperfine Interactions》2001,138(1-4):313-319
Muon catalyzed fusion in deuterium was studied by the MCF collaboration at JINR phasotron. The measurements were carried out
with a high-pressure deuterium target at the JINR phasotron in the temperature range 300–800 K at densities ≃0.5 LHD. The
first experimental results for ddμ-molecule formation rate λ
ddμ in the temperature range 400–800 K with deuterium density 0.5 LHD are presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
A. Adamczak M. P. Faifman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):341-345
The kinetics of muon-catalyzed-fusion processes (μCF) in pure D2 gas have been studied by means of Monte Carlo simulations for various target temperatures and densities. In particular, the
role of resonant and non-resonant ddμ formation in μCF has been investigated. It has been shown that non-resonant formation can be directly observed at very short times in the
neutron time spectra from μCF for low-density D2 targets. The time spectra of neutrons from the low-temperature ortho-D2 and para-D2 gas targets have been calculated. These spectra display a strong ortho-para effect, which agrees with experimental results
for the dilute-gas D2 targets. 相似文献
4.
R. Pohl H. Daniel F. J. Hartmann P. Hauser Y. W. Liu F. Kottmann C. Maierl V. E. Markushin M. Mühlbauer C. Petitjean W. Schott D. Taqqu 《Hyperfine Interactions》2001,138(1-4):35-40
Kinetic energy distributions of muonic hydrogen atoms μp(1S) have been obtained by means of a time-of-flight technique for
hydrogen gas pressures between 4 and 64 hPa. A high energy component of ∼900 eV observed in the data is interpreted as the
signature of long-lived μp(2S) atoms, which are quenched in a non-radiative process leading to the observed high energy: the
collision of a thermalized μp(2S) atom with a hydrogen molecule H2 results in the resonant formation of a {[(ppμ)+]*pee}* molecule. Then the (ppμ)+ complex undergoes Coulomb de-excitation and the ∼1.9 keV excitation energy is shared between a μp(1S) atom and one proton.
The preliminary analysis of the time spectra gives a long-lived μp(2S) population of ∼1% of all stopped muons, and a quenching
rate of ∼4⋅1011 s−1.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
T. Matsuzaki K. Nagamine K. Ishida S.N. Nakamura N. Kawamura M. Tanase M. Kato K. Kurosawa M. Hashimoto H. Sugai K. Kudo N. Takeda G.H. Eaton 《Hyperfine Interactions》1999,118(1-4):229-234
X-ray and neutron measurements were carried out for muon catalyzed fusion and related phenomena in solid T2. The X-ray originated from the μ- to α sticking in muon catalyzed fusion; t + t + μ
-
→ (μ
-
α) + 2n was measured for the first time, yielding K
α
X-ray intensity of (μα) atom and the intensity ratio of K
β
to K
α
. Utilizing the phenomena of 3He accumulation in solid T2, the X-ray in the μ- transfer process from (tμ) to 3He was detected, providing a formation rate and radiative decay branching-ratio of (t
3Heμ) molecule. From fusion neutron measurements, estimated values were obtained for (ttμ) molecular formation rate as well as sticking probability ωt in ttμ fusion. A possible new insight in t + t fusion reaction process at a low energy limit is also obtained.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
F. Mulhauser A. Adamczak G. A. Beer V. M. Bystritsky M. Filipowicz M. C. Fujiwara T. M. Huber R. Jacot-Guillarmod P. Kammel S. K. Kim P. Knowles A. R. Kunselman M. Maier V. E. Markushin G. M. Marshall A. Olin C. Petitjean T. A. Porcelli V. A. Stolupin J. Woźniak J. Zmeskal 《Hyperfine Interactions》2001,138(1-4):41-46
The TRIUMF E742 experiment has measured the energy dependence of the scattering cross-sections of muonic deuterium and tritium
on hydrogen molecules for collisions in the energy range 0.1–45 eV. The experimental setup permits the creation of muonic
atom (μd or μt) beams. The multilayered target system gives the possibility to choose the type of interactions to study and to isolate a
particular interaction. The scattering of μd or μt beams on H2 is analyzed via the muon transfer reaction to neon. The time-of-flight method is used to measure the scattering cross section
as a function of the energy of the muonic atom beam. The results are compared, using Monte Carlo simulations, with theoretical
calculations which have been recently performed with high accuracy.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
The influence of resonances on the muon transfer processes from muonic hydrogen to oxygen and neon (pμ)1s + O8+ → p + (μO)nl7+ and (pμ)1s + Ne10+ → p + (μNe)nl9+ is considered using the Smith lifetime matrix formalism. It is shown that the existence of a long lived resonance in the
case of Ne induces a stronger dependence on collision energy of the muon transfer cross-section for this system.
Present address: Chemistry Department, Vancouver University, Vancouver, BC V6T 1Z3, Canada 相似文献
8.
C. Petitjean D.V. Balin W.H. Breunlich T. Case K.M. Crowe H. Daniel M.P. Faifman V.A. Ganzha B. Gartner F.J. Hartmann P. Kammel S. Kozlov B. Lauss E.M. Maev V.E. Markushin Yu.A. Misko M. Mühlbauer G.E. Petrov W. Prymas G.N. Schapkin W. Schott G.G. Semenchuk Yu.V. Smirenin V.A. Trofimov A.A. Vasiliev A.A. Vorobyov N.I. Voropaev J. Zmeskal 《Hyperfine Interactions》1999,118(1-4):127-133
We present the results of an experiment performed at PSI to investigate muon catalyzed fusion in pure deuterium gas of 5%
density (LHD) at temperatures ranging from 28 K to 350 K. Using a new high pressure ionization chamber the reactions dd → n + 3He and dd → p+t were observed with 100% detection efficiency. The rates of dμd formation were measured with the absolute precision of 1% and the μd spin-flip rates with 0.5%. The temperature dependence of molecular formation and spin-flip rates display pronounced resonance
structures. A preliminary fit based on the Vesman mechanism of resonant muonic molecule formation was carried out yielding
a dd fusion rate of 3.5·108 s-1 and a hfs splitting energy
of 24.3 meV, both in good agreement with the theory.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Surprisingly, Np2Rh2Sn does not order magnetically whereas the uranium counterpart U2Rh2Sn orders antiferromagnetically at 24 K with a 5f moment μ
U
≈0.38μ
B
. We have investigated the magnetic and electronic properties of (U1−x
Np
x
)2Rh2Sn solid solutions. For x=0.25 and 0.5, the ordering temperature decreases to 11 K whereas the Np-rich compound (x=0.75) shows the onset of magnetic order around T≈6 K. The average Np magnetic moment amounts to 0.84 μ
B
,0.83μ
B
and 0.25 μ
B
respectively. The isomer shift slightly decreases, from −9.6 mm/s to −10.4 mm/s (versus NpAl2) as x increases. The values of the quadrupole interaction parameter in the ordered and paramagnetic state suggest that Np moments
are parallel to c for x=0.25 and then rotate to the basal plane for higher x.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
10.
G. A. Kozlov 《Physics of Particles and Nuclei》2010,41(6):954-956
A field model for a quark and an antiquark binding is described. Quarks interact via a gauge unparticle (“ungluon”). The model
is formulated in terms of Lagrangian which features the source field S(x) which becomes a local pseudo-Goldstone field of conformal symmetry — the pseudodilaton mode and from which the gauge non-primary
unparticle field is derived by B
μ(x) ∼ ∂μ
S(x). Because the conformal sector is strongly coupled, the mode S(x) may be one of new states accessible at high energies. We have carried out an analysis of the important quantity that enters
in the “ungluon” exchange pattern — the “ungluon” propagator. 相似文献
11.
A one parameter quantum deformationS
μ
L(2,ℂ) ofSL(2,ℂ) is introduced and investigated. An analog of the Iwasawa decomposition is proved. The compact part of this decomposition
coincides withS
μ
U(2), whereas the solvable part is identified as a Pontryagin dual ofS
μ
U(2). It shows thatS
μ
L(2,ℂ) is the result of the dual version of Drinfeld's double group construction applied toS
μ
U(2). The same construction applied to any compact quantum groupG
c
is discussed in detail. In particular the explicit formulae for the Haar measures on the Pontryagin dualG
d
ofG
c
and on the double groupG are given. We show that there exists remarkable 1-1 correspondence between representations ofG and bicovariant bimodules (“tensor bundles”) overG
c
. The theory of smooth representations ofS
μ
L(2,ℂ) is the same as that ofSL(2,ℂ) (Clebsh-Gordon coefficients are however modified). The corresponding “tame” bicovariant bimodules onS
μ
U(2) are classified. An application to 4D
+ differential calculus is presented. The nonsmooth case is also discussed. 相似文献
12.
On page 905, the second sentence after Eq. (18) should read: “If here the surface t=0 is taken as the surface of integration and the fact that the modes R
μ=0 for z<0 and are functionally the same as the Fulling modes (3) for z>0 is taken into account, then after making the change of variables (8) it might seem that (R
μ,φ)M=(Φμ, φ)R.”
The online version of the original article can be found at 相似文献
13.
The results of an experiment on muon catalyzed dd-fussion in HD gas are presented. The experiment was performed at the muon beam of PSI using a high-pressure ionization chamber
filled with pure HD-gas of low D2 concentration on the level 1%, at temperatures 50, 150 and 300 K. The non-resonant character of ddμ-molecule formation on HD molecules was confirmed by measuring the ratio of yields of the two ddμ-fusion channels, R=Y(3He,n)/Y(3H,p), which proved to be close to unity. The ddμ formation rate was found to vary from λddμ-HD=0.05· 106 s-1 at T=50 K to λddμ-HD=0.12· 106 s-1 at T=300 K, in agreement with the theoretical prediction. A prominent peak at t<60 ns was observed in the time spectrum of fusion neutrons indicating a resonant contribution of ddμ formation from epithermal dμ atoms.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
W. Schwarz E. H. Brandt K. -P. Döring U. Essmann K. Fürderer M. Gladisch D. Herlach G. Majer H. -J. Mundinger H. Orth A. Seeger M. Schmolz 《Hyperfine Interactions》1986,31(1-4):247-253
The diffusivityD
μ of positive muons (μ+) in the mixed state of superconducting high-purity, high-perfection niobium single crystals is investigated by measurements
of the relaxation of the transverse muon spin polarization (μ+SR). The method makes use of the strong magnetic field gradients existing in the mixed state of Type-II superconductors and
monitorsD
μ through the variation of the magnetic field felt by the μ+ during their diffusion through the crystals. For μ+ near the centres of the flux lines inNb it givesD
μ(4.6 K)=(8±2)·10−11m2S−1. The positive temperature coefficient ofD
μ indicates that at liquid-helium temperatures the diffusivity of μ+ inNb is mainly due to phonon-assisted tunnelling processes. 相似文献
15.
V. V. Skobelev 《Journal of Experimental and Theoretical Physics》1997,85(1):13-16
We consider axion formation processes in the synchrotron (e
−→e
−
a) and annihilation (e
−
e
+→a) channels in a constant crossed field F
μν
Fμν=Fμν*F
μν
=0, which approximates constant fields of other configurations in the ultrarelativistic asymptotic limit. The probability
and intensity of axion emission are obtained, and we analyze the energy and field asymptotics. A comparison with the characteristic
neutrino channel
yields the constraints on the axion mass and the energy scale for Peccei-Quinn symmetry breaking. Possible astrophysical
applications are discussed.
Zh. éksp. Teor. Fiz. 112, 25–31 (July 1997) 相似文献
16.
The field dependence of the vibrational contribution to the dynamic magnetic permeability μ
V(H) is calculated for a thin (of thickness d∼λ) high-T
c superconducting wafer in a magnetic field parallel to the surface. The resulting curves are plotted on the basis of an exact
numerical analysis of the vortex structures both for the thermodynamic-equilibrium vortex lattice and in the presence of pinning
forces and the Bean-Livingston surface barrier. It is shown that the μ
V(H) curves are highly sensitive to the size factor (d/λ) and exhibit abrupt changes corresponding to a change in the number of vortex rows. The equilibrium μ
V(H) curve is found to be similar in its general behavior and absolute value (obtained with allowance for the distribution of
grain sizes and with appropriate values of λ and ϰ) to the experimental μ
V(H) curve plotted at nitrogen temperature for fine-grained YBa2Cu3Ox with grain diameters 〈D〉∼λ in an increasing magnetic field. It is established that the main cause of the experimentally observed irreversible behavior
of the μ
V(H) curves during cyclic variation of the applied magnetic field is the existence of a surface barrier to the exit of vortices
from the superconductor. The lower limit H
min(B) of stability of the mixed state in the presence of an ideal surface barrier in a thin, high-T
c superconducting wafer (d∼λ) is determined, along with the range of the vortex state (H
max-H
min) for a fixed number of vortices in micrometer-size grains of the investigated YBaCuO samples.
Fiz. Tverd. Tela (St. Petersburg) 39, 1943–1947 (November 1997) 相似文献
17.
E. Leber S. Barsotti I.I. Fabrikant J.M. Weber M.-W. Ruf H. Hotop 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):125-131
Using a high resolution ( meV) laser photoelectron attachment method, we have studied the formation of (CO 2)
q
− ions (q = 4−22) in collisions of low energy electrons (1−180 meV) with (CO2)
N
() clusters. The previously reported “zero energy resonance”, observed at much larger electron bandwidths, actually consists
of several narrow vibrational Feshbach resonances of the type [(CO 2)
N
−1CO which involve a vibrationally-excited molecular constituent ( denotes vibrational mode) and a diffuse electron weakly bound to the cluster by long range forces. The resonances occur at
energies below those of the vibrational excitation energies of the neutral clusters [(CO 2)
N
−1CO ]; the redshift rises with increasing cluster ion size q by about 12 meV per unit; these findings are recovered by a simple model calculation for the size dependent binding energies.
The size distribution in the cluster anion mass spectrum, resulting from attachment of very slow electrons, mainly reflects
the amount of overlap of solvation-shifted vibrational resonances with zero energy; the cluster anion size q is identical with or close to that of the attaching neutral cluster.
Received 11 January 2000 and Received in final form 10 April 2000 相似文献
18.
Nariyuki Minami 《Communications in Mathematical Physics》2000,213(1):203-247
Let f(ϕ) be a positive continuous function on 0 ≤ϕ≤Θ, where Θ≤ 2 π, and let ξ be the number of two-dimensional lattice points in
the domain Π
R
(f) between the curves r=(R+c
1/R)f(ϕ) and r=(R+c
2/R)f(ϕ), where c
1<c
2 are fixed. Randomizing the function f according to a probability law P, and the parameter R according to the uniform distribution μ
L
on the interval [a
1
L,a
2
L], Sinai showed that the distribution of ξ under P×μ
L
converges to a mixture of the Poisson distributions as L→∞. Later Major showed that for P-almost all f, the distribution of ξ under μ
L
converges to a Poisson distribution as L→∞. In this note, we shall give shorter and more transparent proofs to these interesting theorems, at the same time extending
the class of P and strengthening the statement of Sinai.
Received: 15 June 1999 / Accepted: 11 February 2000 相似文献
19.
The Born model is used as a method to assess the ionicity and the extent of covalent contribution to the binding in lead chloride.
In the process, the Madelung constant (11·2429 with respect to cube root of unit cell volume) and cohesive energy (W
L) (484 kcal/mole) are evaluated. The theoreticalW
L, when compared with that derived from a thermochemical cycle indicates that PbCl2 can be considered to be ‘predominantly ionic’. 相似文献
20.
M. Wolf J. Ahrens R. Beck V. Hejny J.D. Kellie M. Kotulla B. Krusche V. Kuhr R. Leukel V. Metag J.C. Nacher R. Novotny V. Olmos de León R.O. Owens F. Rambo A. Schmidt M. Schumacher U. Siodlaczek H. Ströher J. Weiß F. Wissmann 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):5-8
Double neutral pion photoproduction from the proton has been measured at MAMI for photon energies between threshold and 820
MeV. The reaction was identified by an invariant mass and missing mass analysis. From threshold up to 370 MeV the total cross-section
does not exceed 30 nb. For higher energies it shows a smooth rise until it reaches a maximum of about 10 μb at E
γ = 740 MeV. Dalitz plots of m
2(π0π0) versus
m
2(p,π0) for seven bins of incident photon energy have been analysed. For E
γ > 610 MeV, a strong contribution of a sequential decay is observed with the Δ(1232)-resonance as intermediate state. A comparison
to model calculations shows that these sequential decays presumably originate from the D
13(1520) and also the P
11(1440)-resonance.
Received: 6 June 2000 / Accepted: 18 August 2000 相似文献