Measurement of Z0 decays to hadrons, and a precise determination of the number of neutrino species

We have made a precise measurement of the cross section for e+e--->Z0-->hadrons with the L3 detector at LEP, covering the range from 88.28 to 95.04 GeV. From a fit to the Z0 mass, total width, and the hadronic cross section to be MZ0=91.160 +/- 0.024 (experiment) +/-0.030(LEP) GeV, [Gamma]Z0=2.539+/-0.054 GeV, and [sigma]h(MZ0)=29.5+/-0.7 nb. We also used the fit to the Z0 peak cross section and the width todetermine [Gamma]invisible=0.548+/-0.029 GeV, which corresponds to 3.29+/-0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4[sigma] confidence level.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28683/3/0000500.pd

A measurement of the Z0 leptonic partial widths and the vector and axial vector coupling constants

We have measured the partial widths of the Z0 into lepton pairs, and the forward-backward charge asymmetry for the process e+e--->[mu]+[mu]- using the L3 detector at LEP. We obtain an average [Gamma]ll of 83.0+/-2.1+/-1.1 MeV.From this result and the asymmetry measurement, we extract the values of the vector and axial vector couplings of the Z0 to leptons: grmv=-0.066-0.027+0.046 and grmA= -0.495-0.007+0.007.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28666/3/0000483.pd

Search for neutral MSSM Higgs bosons at LEP.

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of “benchmark” models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter cosβ and, in some scenarios, on the masses of neutral Higgs bosons

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