Standard Higgs boson searches at LEP 2 Original Research Article

The process e+e− → bb−− with − = v or − = charged lepton or − = u, d the range of LEP 2 energies. In the near future LEP 2 will represent a unique opportunity for a direct search of a Higgs boson of mass > 65 GeV. The whole emphasis has been put on a selfconsistent study of the standard Higgs boson properties. Indeed there is the actual possibility of testing a calculation which uses the full matrix elements for e+e−- annihilation into four fermions with the experimental data, beyond the usual approximation of computing production cross section times branching ratios of Higgs into decay products. Of course, given the fact that the number of collected events at LEP 2 will be limited and because of the low statistics one could proceed with a different strategy: for discovery physics elaborated tools are unnecessary. However, the precise theoretical calculation is at our disposal already now, thanks to the combined effort of several groups, and it is extremely interesting and appealing to apply the corresponding machinery to an analysis - as complete as possible - of standard Higgs boson physics. Calculation of the total cross sections and of different kinds of differential distributions at the partonic level are made available to access the widest information for choosing cuts, for discussing the physics of a standard Higgs boson with a mass around 90 GeV where the Higgs and the Z signal become degenerate and for a comprehensive analysis of the various background components.