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171.
L. Adiels G. Backenstoss I. Bergström S. Carius S. Charalambous M. D. Cooper Ch. Findeisen D. Hatzifotiadou M. Hugi A. Kerek H. O. Meyer P. Pavlopoulos J. Repond L. Tauscher D. Troester M. C. S. Williams K. Zioutas 《Zeitschrift fur Physik C Particles and Fields》1989,42(1):49-58
The inclusive η-momentum spectrum from \(\bar p\) annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for $$\begin{gathered} p\bar p \to \eta \omega \left( {1.04_{ - 0.10}^{ + 0.09} } \right)\% ,\eta \rho ^0 \left( {0.53_{ - 0.08}^{ + 0.20} } \right)\% , \hfill \\ \pi a_2 \left( {8.49_{ - 1.10}^{ + 1.05} } \right)\% ,\eta \pi ^0 \left( {1.33 \pm 0.27} \right) \times 10^{ - 4} , \hfill \\ \end{gathered} $$ , and ηη(8.1±3.1)×10?5. An upper limit for \(p\bar p \to \eta \eta '\) of 1.8×10?4 at 95% CL was found. The ratio of the branching ratios is BR(η?)/BR(ηω)=0.51 ?0.06 +0.20 . For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηπ0)/BR(π0π0)=0.65±0.14, BR(ηη)/BR(π0π0), BR(η η ′ )/BR(π0π0) at 95% CL, and BR(ηη)/BR(ηπ0). 相似文献
172.
173.
T.G.V.M. RaoA. Rupesh Kumar Ch. Kalyan ChakravarthiM. Rami Reddy N. Veeraiah 《Physica B: Condensed Matter》2012,407(4):593-597
Homogeneous 40.0 MgO-(10-x) PbF2-50.0 SiO2: x CuO glasses were prepared using melt-quenching technique under controlled conditions. Spectroscopic studies (UV-vis absorption, ESR, FT-IR) are carried out for these glasses. One broad characteristic visible absorption band is observed around 700-850 nm in these glasses, the optical band gap decreases as the content of the CuO increases in the glass network up to 0.7 mol % then reversal trend is observed. ESR spectra of all these glasses show resonance peaks characteristic of Cu2+ ions and hyperfine splitting is resolved with increasing the CuO content in the glass network. From the observed ESR spectra, the spin-Hamiltonian parameters have been evaluated and indicate that Cu2+ ions have octahedral coordination with a strong tetragonal distortion in these glasses. By correlating ESR and optical absorption data, the molecular orbital coefficients have been evaluated. FT-IR spectra give important information about the nature of bonds in the glass matrix. The density of the glasses is also measured and is found to decrease with the increase CuO contents in the glass matrix. The physical parameters along with spectroscopic parameters are measured. 相似文献
174.
X. J. Cheng B. X. Jiang L. Li J. L. Wang Zh. G. Yang W. B. Cheng X. Ch. Shi Y. B. Pan 《Laser Physics》2012,22(4):652-655
Lasers from Yb:YAG ceramic at different temperature were reported in this paper. The Yb:YAG ceramic laser with active-mirror structure was end-pumped by a laser diode whose central wavelength was 940 nm. At 80 K, with doping concentration of 5 at % Yb:YAG ceramic slab, output energy of 0.68 J at 10 Hz repetition rate was obtained under the pump energy of 2.49 J, corresponding to a slope efficiency of 40% and a conversion efficiency of 27.3%, respectively. 相似文献
175.
Fink D Barea J Beck D Blaum K Böhm Ch Borgmann Ch Breitenfeldt M Herfurth F Herlert A Kotila J Kowalska M Kreim S Lunney D Naimi S Rosenbusch M Schwarz S Schweikhard L Simkovic F Stanja J Zuber K 《Physical review letters》2012,108(6):062502
The 110Pd double-β decay Q value was measured with the Penning-trap mass spectrometer ISOLTRAP to be Q=2017.85(64) keV. This value shifted by 14 keV compared with the literature value and is 17 times more precise, resulting in new phase-space factors for the two-neutrino and neutrinoless decay modes. In addition a new set of the relevant matrix elements has been calculated. The expected half-life of the two-neutrino mode was reevaluated as 1.5(6)×10(20) yr. With its high natural abundance, the new results reveal 110Pd to be an excellent candidate for double-β decay studies. 相似文献
176.
177.
We report scanning tunneling microscope measurements showing a substantial decrease of the current, almost to zero, on the Si(111)-(7x7) reconstruction in the near-to-contact region under low bias conditions. First principles simulations for the tip-sample interaction and transport calculations show that this effect is driven by the substantial local modification of the atomic and electronic structure of the surface. The chemical reactivity of the adatom dangling bond states that dominate the electronic density of states close to the Fermi level and their spatial localization result in a strong modification of the electronic current. 相似文献
178.
A novel apparatus for a sensitive test of the independence of the speed of optical waves from the propagation direction has been developed. It employs a monolithic ULE glass structure containing two orthogonal, crossing Fabry-Perot cavities which enable common mode rejection of certain disturbances. Highly accurate locking and cavity frequency read-out are achieved using laser frequency modulation at audio frequencies. Several systematic effects were characterized. Without rotation the root Allan variance (RAV) of the beat frequency reaches a minimum of 0.5 Hz (2 × 10−15) close to the thermal noise floor of the cavities. The performance of the apparatus under rotation is demonstrated by determining with improved accuracy one parameter of the standard model extension test theory, = (−1.0 ± 2.3) × 10−15, under simplifying assumptions. 相似文献
179.
The relaxation of director fields in freely suspended smectic films is studied experimentally by means of polarizing microscopy,
and analyzed by solving the torque balance equation under appropriate initial and boundary conditions. We consider in particular
the role of anchoring conditions of the c-director at particles and defects in the film. The structure of regular relaxation
patterns allows to determine the elastic anisotropy of smectic materials. The splay elastic constant can exceed the bend constant
by a factor of two and more. A remarkable consequence of this anisotropy is the stick-slip-like relaxation around a central
defect of topological strength s = + 1. 相似文献
180.