A search for neutral Higgs bosons decaying into tau pairs is presented using data in p$\bar{p}$ collisions at √s = 1.96 TeV. One of the tau leptons is identified via its decay into an electron or muon and the other via its decay into a hadronic final state. The data, corresponding to an integrated luminosity of around 1.0 fb-1, were collected with the D0 detector at the Fermilab Tevatron collider between April 2002 and February 2006. No significant excess of events above the background expectation is observed and limits on the cross section times branching ratio for neutral Higgs bosons decaying into tau pairs, p$\bar{p}$ → [Phi] → [tau]+[tau]-, are set. The cross section limits are interpreted as exclusions in the parameter space of the minimal supersymmetric Standard Model, resulting in exclusions in the range 40

A search for the production of neutral Higgs bosons ? decaying into ?+?− final states in p{bar p} collisions at a center-of-mass energy of 1.96 TeV is presented. The data, corresponding to an integrated luminosity of approximately 325 pb−1, were collected by the D0 experiment at the Fermilab Tevatron Collider. Since no excess compared to the expectation from standard model processes is found, limits on the production cross section times branching ratio are set. The results are combined with those obtained from the D0 search for ?b({bar b}) → b{bar b}b({bar b}) and are interpreted in the minimal supersymmetric standard model.

The work presented in this thesis spans a wide range of experimental particle physics subjects, starting from level-1 trigger electronics to the final results of the search for Higgs boson decay and to tau lepton pairs. The thesis describes an innovative reconstruction algorithm for tau decays and details how it was instrumental in providing a measurement of Z decay to tau lepton pairs. The reliability of the analysis is fully established by this measurement before the Higgs boson decay to tau lepton pairs is considered. The work described here continues to serve as a model for analysing CMS Higgs to tau leptons measurements.

We report results from a search for neutral Higgs bosons produced in association with b quarks using data recorded by the D0 experiment at the Fermilab Tevatron Collider and corresponding to an integrated luminosity of 7.3 fb−1. This production mode can be enhanced in several extensions of the standard model (SM) such as in its minimal supersymmetric extension (MSSM) at high tan [beta]. We search for Higgs bosons decaying to tau pairs with one tau decaying to a muon and neutrinos and the other to hadrons. The data are found to be consistent with SM expectations, and we set upper limits on the cross section times branching ratio in the Higgs boson mass range from 90 to 320 GeV/c2. We interpret our result in the MSSM parameter space, excluding tan [beta] values down to 25 for Higgs boson masses below 170 GeV/c2.