Search for the Higgs boson in the ZH → νν-bar bb-bar channel with the D0 experiment at the TeVatron

The origin of the electroweak symmetry breaking is one the pending questions at the beginning of the 21. century. Imagined in the 1960's, the Higgs mechanism offers a theoretical solution to this problem, while predicting a new particle, the Higgs boson, undiscovered up to now. This particle has been searched with the DO detector at the Tevatron hadronic collider, with a center of mass energy of 1,96 TeV. The analysis channel is ZH → νν-bar bb-bar. For this search, an optimization of the trigger conditions specific to signals with jets plus missing transverse energy final states has been performed. Moreover, a tool was designed to measure the corresponding efficiencies. A precise determination of the jet energies is also an essential ingredient for this analysis. A method was developed in order to correct the simulated jets for the differences observed in jet energy scale, energy resolution and reconstruction efficiency between data and simulation. The data analysis, performed with an integrated luminosity of 2.1 fb-1, did not reveal any excess. For a Higgs boson mass of 115 GeV, a limit has been set at 95% C.L. on the cross section times branching fraction of (pp-barb → H(Z/W)) x (H → bar bb-bar), which is 7.5 times larger than the standard model value. (author)