The DØ experiment is based at the Tevatron, which is currently the world's highest-energy accelerator. The detector comprises three major subsystems: the tracking system, the calorimeter and the muon detector. Jets, seen in the calorimeter, are the most common product of the proton-proton interactions at 2TeV. This thesis is divided into two parts. The first part focuses on jets and describes the derivation of a jet energy scale using pp →(Z + jets) events as a cross-check of the official DØ

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... energy scale (Versions 4.2 and 5.1) which is derived using pp → γ+jets events. Closure tests were also carried out on the jet energy calibration as a further verification. Jets from b-quarks are commonly produced at D O, readily identified and are a useful physics tool. These require a special correction in the case where the b-jet decays via a muon and a neutrino. Thus a semileptonic correction was also derived as an addition to the standard energy correction for jets. The search for the Higgs boson is one of the largest physics programmes at D O. The second part of this thesis describes a search for the Standard Model Higgs boson in the ZH → ννbb channel in 52f b −1 of data. The analysis is based on a sequence of event selection criteria optimised on Monte Carlo event samples that simulate four light Higgs boson masses between 105 GeV and 135GeV and the main backgrounds. For the first time, the data for the analysis are selected using new acoplanarity triggers and the b-quark jets are selected using the DØ neural net b-jet tagging tool. A limit is set for σ(pp → ZH) × Br(H → bb). 3