排序方式: 共有72条查询结果,搜索用时 15 毫秒
21.
M.C. Fujiwara J.M. Bailey G.A. Beer J.L. Beveridge J.L. Douglas T.M. Huber R. Jacot‐Guillarmod P. Kammel S.K. Kim P.E. Knowles A.R. Kunselman M. Maier V.E. Markushin G.M. Marshall C.J. Martoff G.R. Mason F. Mulhauser A. Olin C. Petitjean T.A. Porcelli J. Zmeskal 《Hyperfine Interactions》1997,106(1-4):257-264
The emission of muonic tritium atoms from a thin film of hydrogen isotopes into vacuum was observed. The time and position
of the muon decays were measured by tracking the decay electron trajectory. The observations are useful both for testing the
theoretical cross sections for muonic atomic interactions, and producing an atomic beam of slow μ-t with a controllable energy.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
22.
Vorobyov A. A. Balin D. V. Baturin V. N. Grigoriev Yu. S. Maev E. M. Petrov G. E. Semenchuk G. G. Smirenin Yu. V. Voropaev N. I. Deutsch J. Govaerts J. Prieels R. Ackerbauer P. Breunlich W. H. Kammel P. Lauss B. Marton J. Prymas W. Egger J. Petitjean C. Petitjean Th. van den Brandt B. Daniel H. Hartmann F. J. Mühlbauer M. Schott W. von Egidy T. Wojciechowski P. Case T. Crowe K. M. Markushin V. E. Beer G. A. 《Hyperfine Interactions》1996,101(1):413-421
In this article we report the results of an experiment performed in 1993 at PSI. The goal was to determine the absolute rate of nuclear muon capture by3He. In the experiment we used a new technique recently developed at Gatchina. As a preliminary result from this experiment we obtained
c=(1496±3(stat)-3(syst)) s–1. 相似文献
23.
V. E. Markushin E. I. Afanasieva T. Case K. Lou C. Petitjean 《Hyperfine Interactions》1993,82(1-4):373-389
The results of a Monte Carlo simulation of muon catalyzed fusion in H/D/T mixtures at low deuterium and tritium concentrations are presented, and the kinetics of the dt branch of the CF cycle is discussed. It is shown that the epithermal effects in the dt cycle produce a multicomponent structure in the time spectra of dt fusion, in agreement with the recent experimental results obtained by the CF collaboration at PSI. The importance of further studies of the CF reactions in triple mixtures is emphasized. 相似文献
24.
T.S. Jensen V.E. Markushin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):271-283
The atomic cascades in μ- p and p atoms have been studied in detail using new results for the cross-sections of the scattering of highly excited exotic atoms from molecular hydrogen. The cascade calculations have been done with an updated version of the extended standard cascade model that computes the evolution in the kinetic energy from the beginning of the cascade. The resulting X-ray yields, kinetic energy distributions, and cascade times are compared with the experimental data. 相似文献
25.
T.S. Jensen V.E. Markushin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(2):165-181
The differential and total cross-sections for the scattering of muonic, pionic, kaonic and antiprotonic hydrogen in excited
states from atomic hydrogen have been calculated for the purpose of atomic cascade calculations. The scattering problem is
treated in a fully quantum mechanical framework which takes the energy shifts and, in the case of the hadronic atoms, the
widths of the ns states into account. The validity of semiclassical approximations is critically examined.
Received 4 December 2001 and Received in final form 4 February 2002 相似文献
26.
N. I. Voropaev D. V. Balin W. H. Breunlich T. Case K. M. Crowe M. P. Faifman B. Gartner F. J. Hartmann P. Kammel B. Lauss E. M. Maev V. E. Markushin C. Petitjean G. E. Petrov G. N. Schapkin G. G. Semenchuk A. A. Vorobyov J. Zmeskal 《Hyperfine Interactions》2001,138(1-4):331-341
During 1994–1996, a series of μCF experiments were performed at PSI by the PSI-PNPI-IMEP-LBNL-TUM collaboration. These experiments
aimed at high-precision studies of the d–μ–d fusion in D2 and HD gases in a wide temperature range. The Gatchina ionization time projection chamber has been used to detect the dd-fusion
reaction products. The main parameters of the d–μ–d fusion have been measured with high absolute precision. In this report,
we present the results of the final analysis of the experimental data. The obtained results are compared with the calculations
based on a recent μCF-theory.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
27.
D. F. Anagnostopoulos S. Biri G. Borchert W. Breunlich M. Cargnelli J.-P. Egger H. Fuhrmann D. Gotta M. Giersch A. Gruber M. Hennebach P. Indelicato T. S. Jensen F. Kottmann Y.-W. Liu B. Manil V. M. Markushin J. Marton N. Nelms G. C. Oades G. Rasche P. A. Schmelzbach L. M. Simons J. Zmeskal 《Hyperfine Interactions》2001,138(1-4):131-140
The measurement of the strong-interaction effects in pionic hydrogen gives access to fundamental properties of the pion–nucleon
interaction. Methods developed within the framework of Heavy-Baryon Chiral Perturbation Theory allow calculations with an
accuracy of a few per cent, which should be tested by experiment.
Techniques advanced for recent experiments on the precision spectroscopy of X-rays from antiprotonic and pionic atoms will
be used in a new series of measurements for pionic hydrogen. The aim is to achieve finally an accuracy of 0.2% for the hadronic
shift ∈1s
and most important of about 1% for the broadening Γ1s
.
An essential part of the experimental program is an improved understanding of the atomic cascade. At first, the value of ∈1s
has to be proven not to be influenced by molecular formation. Secondly, a more accurate determination of Γ1s
requires a detailed study of Coulomb deexcitation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
28.
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
29.
P. Kammel V. A. Andreev D. V. Balin R. M. Carey T. Case D. B. Chitwood S. M. Clayton K. M. Crowe J. Deutsch P. T. Debevec P. U. Dick A. Dijksman J. Egger D. Fahrni A. A. Fetisov S. J. Freedman V. A. Ganzha B. Gartner J. Govaerts F. E. Gray F. J. Hartmann W. D. Herold D. W. Hertzog V. I. Jatsoura A. G. Krivshich B. Lauss E. M. Maev O. E. Maev V. E. Markushin C. J. G. Onderwater C. Petitjean G. E. Petrov C. C. Polly R. Prieels S. M. Sadetsky G. N. Schapkin R. Schmidt G. G. Semenchuk M. Soroka A. A. Vorobyov N. I. Voropaev 《Hyperfine Interactions》2001,138(1-4):435-443
The aim of the μCap experiment is a 1% measurement of the singlet capture rate Λ
S
for the basic electro-weak reaction μ + p → n + νμ. This observable is sensitive to the weak form-factors of the nucleon, in particular to the induced pseudoscalar coupling
constant g
P
. It will provide a rigorous test of theoretical predictions based on the Standard Model and effective theories of QCD. The
present method is based on high precision lifetime measurements of μ− in hydrogen gas and the comparison with the free μ+ lifetime. The μ− experiment will be performed in ultra-clean, deuterium-depleted H2 gas at 10 bar. Low density compared to liquid H2 is chosen to avoid uncertainties due to ppμ formation. A time projection chamber acts as a pure hydrogen active target. It defines the muon stop position in 3D and
detects rare background reactions. Decay electrons are tracked in cylindrical wire-chambers and a scintillator array covering
75% of 4π.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
30.
Taqqu D. Brunnhuber A. Daniel H. Hartmann F. J. Hauser P. Kottmann F. Maierl C. Markushin V. Mühlbauer M. Petitjean C. Schott W. Wojciechowski P. 《Hyperfine Interactions》1996,101(1):599-605
Very recent results relevant to the planning of laser spectroscopy of the 2s-2p splitting in the µp atom are presented. An experimental configuration providing a sufficiently small muon stopping volume at the lowest pressures has been tested. The first experimental indications for the existence of a long-lived 2s fraction at low pressure are discussed. 相似文献