Search for neutralino pair production at √s = 189 GeV

A search for pair-production of neutralinos at a LEP centre-of-mass energy of 189 GeV gave no evidence for a signal. This limits the neutralino production cross-section and excludes regions in the parameter space of the Minimal Supersymmetric Standard Model (MSSM)

The reaction e+e−→γγ(γ)e^+e^- \rightarrow \gamma\gamma(\gamma) at Z0^0 energies

Many different approaches to the geometric and statistical analysis of document layouts have been proposed in the literature. The development of practical branchand- bound algorithms for solving geometric matching problems under noise and uncertainty has enabled the formulation of new classes of geometric layout analysis methods based on globally optimal maximum likelihood interpretations for well-defined models of the spatial statistics of document images. I review this approach to geometric layout analysis using text line finding and column finding in the presence of noise and uncertainty as examples and compare the approach with selected other statistical and geometric layout analysis methods

Measurement of trilinear gauge boson couplings WWV, (V = Z, gamma) in e+ e- collisions at 189-GeV

Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identified lepton and X missing four-momentum. The observations are consistent with the predictions of the Standard Model.Comment: 20 pages, 4 figures, Accepted by Phys. Lett.

Strange Baryon Production in Z Hadronic Decays

A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the ∑± average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models. © 1995 Springer-Verlag.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Search for R-parity violation with a UˉDˉDˉ\bar{U} \bar{D} \bar{D} coupling at s\sqrt{s} = 189 GeV

Searches for pair production of gauginos and squarks in $e^{+} e^{-}$ collisions at a centre-of-mass energy of 189 GeV have been performed on data corresponding to an integrated luminosity of 158 pb$^{-1}$ collected by the DELPHI detector at LEP. The data were analyzed under the assumption of non-conservation of \mbox{$R$-parity} through a single dominant $\bar{U} \bar{D} \bar{D}$~coupling between squarks and quarks. Typical final states contain between 4 and 10 jets with or without additional leptons. No excess of data above Standard Model expectations was observed. The results were used to constrain domains of the MSSM parameter space and derive limits on the masses of supersymmetric particles. The following mass limits at 95\% CL were obtained from these searches: \begin{itemize} \item neutralino mass: $m_{\tilde{\chi^0_{1}}} \ge 32$ GeV \item chargino mass: $m_{\tilde{\chi^+_{1}}} \ge 94$ GeV \item stop and sbottom mass (indirect decay) with $\Delta M 5$ GeV: $m_{\tilde{t_{1}}} \ge 74$ GeV, for $\Phi_{mix}=0$ rad $m_{\tilde{t_{1}}} \ge 59$ GeV, for $\Phi_{mix}=0.98$ rad $m_{\tilde{b_{1}}} \ge 72$ GeV, for $\Phi_{mix}=0$ rad. \end{itemize} The angle $\phi_{mix}$ is the mixing angle between left and right handed quarks

Measurement of the mass of the Z boson and the energy calibration of LEP

In 1985 the French government created a unique circuit for the dissemination of doctoral theses: References went to a national database “Téléthèses” whereas the documents were distributed to the university libraries in microform. In the era of the electronic document this French network of deposit of and access to doctoral theses is changing. How do you discover and locate a French thesis today, how do you get hold of a paper copy and how do you access the full electronic text? What are the catalogues and databases referencing theses since the disappearance of “Téléthèses”? Where are the archives, and are they open? What is the legal environment that rules the emerging structures and tools? This paper presents national plans on referencing and archiving doctoral theses coordinated by the government as well as some initiatives for creating full text archives. These initiatives come from universities as well as from research institutions and learned societies. “Téléthèses” records have been integrated in a union catalogue of French university libraries SUDOC. University of Lyon-2 and INSA Lyon developed procedures and tools covering the entire production chain from writing to the final access in an archive: “Cyberthèses” and “Cither”. The CNRS Centre for Direct Scientific Communication at Lyon (CCSD) maintains an archive (“TEL”) with about 2000 theses in all disciplines. Another repository for theses in engineering, economics and management called “Pastel” is proposed by the Paris Institute of Technology (ParisTech), a consortium of 10 engineering and commercial schools of the Paris region