W mass measurement at LEP
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  R. Chierici (Torino University)

Abstract:
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The determination of the mass of the W boson at LEP2 will be reviewed.
In its second period of run, LEP has a unique opportunity to study W 
boson pair production from e+e- annihilations; high luminosity and 
energy allow to enter the high precision regime for the determination 
of the W mass, with implications of utmost importance for the 
constraining of the Standard Model.
The techniques for the determination of m_W in all W+W- decay channels
and the preliminary results obtained at LEP2 combining all the data
up to sqrt(s)=189 GeV will be presented and discussed.  
Conclusions and an outlook to the scenario after LEP will follow.