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51.
The DELPHI Collaboration J. Abdallah et al. 《The European Physical Journal C - Particles and Fields》2003,27(2):153-172
A search for sleptons, neutralinos, charginos, sgoldstinos and heavy stable charged sleptons in the context of scenarios
where the lightest supersymmetric particle is the gravitino, is presented. Data collected during 2000 with the DELPHI detector
at centre-of-mass energies from 204 to 208 GeV were analysed and combined with all the data collected from 1995 to 1999 at
lower energies. No evidence for the production of sleptons, neutralinos and charginos has been found, therefore new limits
on the mass of these supersymmetric particles and on the model parameter space are set. The search for heavy stable charged
sleptons also updates the stable sleptons mass limit. The absence of evidence for sgoldstino production allows limits to be
set on its mass and on the scale of supersymmetry breaking.
Received: 6 November 2002 / Published online: 14 February 2003 相似文献
52.
53.
Abstract We study a perturbed anisotropic equation without using the knowledge of the limiting problem. This provides a different method
from that introduced by Brézis and Nirenberg [4]. Our arguments use some tools recently developed in [5, 6].
Keywords: Anisotropic critical exponent, Critical level, Compactness, Nehari manifold
Mathematics Subject Classification (2000): 35J25, 35J60, 35J65 相似文献
54.
M. Serpentini A. Souifi M. Abdallah I. Berbezier G. Bremond 《Journal of luminescence》1998,80(1-4):515-518
In this paper, we present a photoluminescence (PL) study of Si/Ge/SiGe/Si structures grown by gas source molecular beam epitaxy on an (1 1 8) undulated surface with various Ge coverage. Nucleation and growth of Ge films is obtained by the Stranski–Krastanov mechanism. The influence of the substrate orientation on the changeover 2D–3D growth mode is investigated. Furthermore, we show the use of growing an SiGe wetting layer to control the uniformity of the Ge island size. The PL signal related to the Ge islands is found to be highly dependent of the power excitation and is observed up to room temperature. 相似文献
55.
The DELPHI Collaboration J. Abdallah et al. 《The European Physical Journal C - Particles and Fields》2003,26(4):505-525
In some supersymmetric models, the gluino () is predicted to be light and stable. In that case, it would hadronize to form R-hadrons. In these models, the missing energy
signature of the lightest supersymmetric particle is no longer valid, even if R-parity is conserved. Therefore, such a gluino
is not constrained by hadron collider results, which looked for the decay . Data collected by the DELPHI detector in 1994 at 91.2 GeV have been analysed to search for events. No deviation from Standard Model predictions is observed and a gluino mass between 2 and 18 GeV/c2 is excluded at the 95% confidence level in these models. Then, R-hadrons produced in the squark decays were searched for
in the data collected by DELPHI at the centre-of-mass energies of 189 to 208 GeV, corresponding to an overall integrated luminosity
of 609 Pb-1. The observed number of events is in agreement with the Standard Model predictions. Limits at 95% confidence level are derived
on the squark masses from the excluded regions in the plane ()
GeV/c2, and GeV/c2 for purely left squarks.
GeV/c2, and GeV/c2 independent of the mixing angle.
Received: 6 November 2002 / Published online: 15 January 2003 相似文献
56.
S. A. Pikuz T. A. Shelkovenko V. M. Ramanova J. Abdallah Jr. G. Csanak R. E. H. Clark A. Ya. Faenov I. Yu. Skobelev D. A. Hammer 《Journal of Experimental and Theoretical Physics》1997,85(3):484-491
The first experimental studies of an electron beam generated in an X pinch on the XP machine (Cornell University, USA) and the BIN machine (P. N. Lebedev Physical Institute, Russian Academy
of Sciences) are reported. It is shown that it is possible in an X pinch to isolate the effect of a plasma-generated electron beam on the multiply charged ion radiation. The intensities of
the satellite lines corresponding to Li-, Be-, B-, and C-like ions are calculated for the Al spectrum on the basis of a collisional-radiative
model with a non-Maxwellian electron distribution in the plasma. The effect of an electron beam on the multiply charged light
ion radiation in an X-pinch plasma is demonstrated. Comparing our calculations with the experimental spectra, we conclude that the present model
can be used to estimate the electron beam intensity.
Zh. éksp. Teor. Fiz. 112, 894–909 (September 1997) 相似文献
57.
58.
59.
In the atomic absorption spectrometric determination of chromium(III), the interfering effects of different complexing agents can be completely eliminated by addition of excess of cyanide, boric acid or sulphosalicyclic acid. The effect of some complexing agents on the production of chromium atoms is discussed, and the mechanism of cyanide interaction is investigated in detail. 相似文献
60.
The inhibition-release titration method has been used to study interference effects in flame atomic-absorption determination of iron. Interferences from anions, cations and complexing agents with the atomic-absorption of iron when a stoichiometric air-acetylene flame is used, can be obviated by a preliminary treatment of the sample solution with sulphosalicylic acid to convert the iron into the same complex before aspiration, thus giving a constant environment for the iron in the flame processes. 相似文献