排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
M. Nuñez Portela E. A. Dijck A. Mohanty H. Bekker J. E. van den Berg G. S. Giri S. Hoekstra C. J. G. Onderwater S. Schlesser R. G. E. Timmermans O. O. Versolato L. Willmann H. W. Wilschut K. Jungmann 《Applied physics. B, Lasers and optics》2014,114(1-2):173-182
A single Ra+ ion stored in a Paul radio frequency ion trap has excellent potential for a precision measurement of the electroweak mixing angle at low momentum transfer and as the most stable optical clock. The effective transport and cooling of singly charged ions of the isotopes 209Ra to 214Ra in a gas filled radio frequency quadrupole device is reported. The absolute frequencies of the transition 7s2S1/2–7d2D3/2 at wavelength 828 nm have been determined in 212–214Ra+ with ≤19 MHz uncertainty using laser spectroscopy on small samples of ions trapped in a linear Paul trap at the online facility Trapped Radioactive Isotopes: µicrolaboratories for fundamental Physics (TRIµP) of the Kernfysisch Versneller Instituut. 相似文献
2.
Energy spectra for decaying 2D turbulence in a bounded domain 总被引:1,自引:0,他引:1
We use results derived in the framework of the replica approach to study the liquid-glass thermodynamic transition. The main results are derived without using replicas and applied to the study of the Lennard-Jones binary mixture introduced by Kob and Andersen. We find that there is a phase transition due to the entropy crisis. We compute both analytically and numerically the value of the phase transition point T(K) and the specific heat in the low temperature phase. 相似文献
3.
Misiejuk A Papandreou Z Voutier E Bauer TS Blok HP Boersma DJ Den Bok HW Bruins EE Farzanpay F Grüner K Hesselink WH Huber GM Jans E Kalantar-Nayestanaki N Kasdorp WJ Konijn J Laget JM Lapikás L Lolos GJ Onderwater GJ Pellegrino A Schroevers R Spaltro CM Starink R van der Steenhoven G Steiger JJ Visschers JL Willering HW Yeomans DM 《Physical review letters》2002,89(17):172501
The differential cross section for electron-induced neutron knockout in the reaction 4He(e,e(')n)(3)He has been measured for the first time with a statistical accuracy of 11%. The experiment was performed in quasielastic kinematics at a momentum transfer of 300 MeV/c and in the missing-momentum range of 25-70 MeV/c. The comparison of the data with theoretical calculations shows an impressive increase of the cross section resulting from final state interaction effects. Specifically, the p-n charge-exchange process dominates the cross section in this kinematical regime. 相似文献
4.
Bennett GW Bousquet B Brown HN Bunce G Carey RM Cushman P Danby GT Debevec PT Deile M Deng H Deninger W Dhawan SK Druzhinin VP Duong L Efstathiadis E Farley FJ Fedotovich GV Giron S Gray FE Grigoriev D Grosse-Perdekamp M Grossmann A Hare MF Hertzog DW Huang X Hughes VW Iwasaki M Jungmann K Kawall D Khazin BI Kindem J Krienen F Kronkvist I Lam A Larsen R Lee YY Logashenko I McNabb R Meng W Mi J Miller JP Morse WM Nikas D Onderwater CJ Orlov Y Ozben CS Paley JM Peng Q Polly CC Pretz J Prigl R 《Physical review letters》2002,89(10):101804
A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm). 相似文献
5.
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
6.
C. J. G. Onderwater 《Hyperfine Interactions》2012,209(1-3):9-14
Twenty years ago, we published a paper entitled “Discovery of antiproton trapping by long-lived metastable states in liquid helium”. In retrospect, this was the discovery of antiprotonic helium atoms, the study of which is actively being done at CERN’s antiproton decelerator. A brief overview of this interesting exotic atom is given, together with some historical background. 相似文献
7.
Webber DM Tishchenko V Peng Q Battu S Carey RM Chitwood DB Crnkovic J Debevec PT Dhamija S Earle W Gafarov A Giovanetti K Gorringe TP Gray FE Hartwig Z Hertzog DW Johnson B Kammel P Kiburg B Kizilgul S Kunkle J Lauss B Logashenko I Lynch KR McNabb R Miller JP Mulhauser F Onderwater CJ Phillips J Rath S Roberts BL Winter P Wolfe B;MuLan Collaboration 《Physical review letters》2011,106(4):041803
We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(μ(+)) (MuLan)=2?196?980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166?378?8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the μ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P). 相似文献
8.
Bennett GW Bousquet B Brown HN Bunce G Carey RM Cushman P Danby GT Debevec PT Deile M Deng H Deninger W Dhawan SK Druzhinin VP Duong L Efstathiadis E Farley FJ Fedotovich GV Giron S Gray FE Grigoriev D Grosse-Perdekamp M Grossmann A Hare MF Hertzog DW Huang X Hughes VW Iwasaki M Jungmann K Kawall D Kawamura M Khazin BI Kindem J Krienen F Kronkvist I Lam A Larsen R Lee YY Logashenko I McNabb R Meng W Mi J Miller JP Mizumachi Y Morse WM Nikas D Onderwater CJ Orlov Y Ozben CS Paley JM Peng Q 《Physical review letters》2008,100(9):091602
The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero delta omega a(=omega a mu+ - omega a mu-) and a sidereal variation of omega a mu+/-). No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ = -(1.0+/-1.1) x 10(-23) GeV; (m mu dZ0 + HXY)=(1.8+/-6.0) x 10(-23) GeV; and the 95% confidence level limits b perpendicular mu+ <1.4 x 10(-24) GeV and b perpendicular mu- <2.6 x 10(-24) GeV. 相似文献
9.
W.-J. Kasdorp W. H. A. Hesselink D. Groep E. Jans N. Kalantar-Nayestanaki L. Lapikás J. J. van Leeuwe A. Misiejuk G. J. L. Nooren C. J. G. Onderwater A. R. Pellegrino C. M. Spaltro R. Starink G. van der Steenhoven J. J. M. Steijger J. A. Templon 《Few-Body Systems》1998,25(1-3):115-132
The reaction H(e, e
p) has been studied at an invariant mass of 1050 MeV, i.e. well below the (1232) resonance. Cross sections have been obtained at values of , the four-momentum transfer squared, of 0.10, 0.20, and 0.28 (GeV/c), covering a missing-momentum range from 150 to 700 MeV/c. The data are compared to the results of covariant calculations of Tjon, and the results of calculations based on a Schr?dinger
formalism due to Laget and the Mainz group, respectively. The data are well described by the calculations of the Mainz group,
whereas they are underestimated by Tjon's calculations at high missing momenta. The calculations of Laget, on the other hand,
overestimate the data at low missing momenta, but give a good account of the data at high missing momenta. More detailed considerations
reveal that the (1232) contributions are dominant at high missing momenta. However, the lacking (1232) contribution in Tjon's calculations is not enough to explain the large discrepancy between his calculation and the
present H(e, ) data at high missing momentum. Probably the deuteron wave function employed in the covariant calculations has a -state contribution that is too small.
Received August 19, 1997; revised January 28, 1998; accepted for publication February 17, 1998 相似文献
10.
Morozov VS Chao AW Krisch AD Leonova MA Raymond RS Sivers DW Wong VK Garishvili A Gebel R Lehrach A Lorentz B Maier R Prasuhn D Stockhorst H Welsch D Hinterberger F Ulbrich K Schnase A Stephenson EJ Brantjes NP Onderwater CJ da Silva M 《Physical review letters》2008,100(5):054801
The Chao matrix formalism allows analytic calculations of a beam's polarization behavior inside a spin resonance. We recently tested its prediction of polarization oscillations occurring in a stored beam of polarized particles near a spin resonance. Using a 1.85 GeV/c polarized deuteron beam stored in the COoler SYnchrotron, we swept a new rf solenoid's frequency rather rapidly through 400 Hz during 100 ms, while varying the distance between the sweep's end frequency and the central frequency of an rf-induced spin resonance. Our measurements of the deuteron's polarization near and inside the resonance agree with the Chao formalism's predicted oscillations. 相似文献