We report results of searches for neutral supersymmetric Higgs Bosons in up to 2.7 fb−1 of data collected with the D0 detector at the Fermilab Tevatron. The final states include muons, taus, and jets from the decay of b hadrons. The searches observe no significant excess and set upper limits on neutral Higgs production cross sections. The limits are also translated into exclusions of MSSM parameter space.

A search for neutral MSSM Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 inverse picobarns recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the MSSM parameter space.

We have performed a search for neutral Higgs bosons produced in association with bottom quarks in p{bar p} collisions, using 260 pb−1 of data collected with the D0 detector in Run II of the Fermilab Tevatron Collider. The cross sections for these processes are enhanced in many extensions of the standard model (SM), such as in its minimal supersymmetric extension at large tan?. The results of our analysis agree with expectations from the SM, and we use our measurements to set upper limits on the production of neutral Higgs bosons in the mass range of 90 to 150 GeV.

The Higgs mechanism preserves the gauge symmetries of the Standard Model while giving masses to the W, Z bosons. Supersymmetry, which protects the Higgs boson mass scale from quantum corrections, predicts at least 5 Higgs bosons, none of which has been directly observed. This thesis presents a search for neutral Higgs bosons, produced in association with bottom quarks. The production rate is greatly enhanced at large values of the Supersymmetric parameter tan {beta}. High-energy p{bar p} collision data, collected from Run II of the Fermilab Tevatron using the D0 detector, are analyzed. In the absence of a signal, values of tan {beta}> 80-120 are excluded at 95% Confidence Level (C.L.), depending on the (CP-odd) neutral Higgs boson mass (studied from 100 to 150 GeV/c{sup 2}).

A search for the neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM), produced in proton-proton collisions recorded by the ATLAS detector, is presented. The data correspond to an integrated luminosity of 20.3 fb−1, with a center of mass energy of 8 TeV. The search focuses on final states where the Higgs bosons decay into a [tau]+[tau]− pair, with one [tau] lepton decaying leptonically and the other hadronically. Two analyses are performed which separately target low-mass and high-mass Higgs bosons, with the former divided into two sub-channels based on the presence or absence of a b-jet in final state. No evidence of new Higgs bosons is found, and upper limits are set on the cross-section times branching ratio of such Higgs bosons, and on the MSSM parameters m [Alpha] and tan [Beta].

A search for neutral Higgs bosons predicted in the minimal supersymmetric standard model (MSSM) for [mu]+[mu]- decay channels is presented. Our analysis uses data collected by the CMS experiment at the LHC in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.3 fb-1, respectively. The search is sensitive to Higgs bosons produced either through the gluon fusion process or in association with a bb quark pair. No statistically significant excess is observed in the [mu]+[mu]- mass spectrum. Results are interpreted in the framework of several benchmark scenarios, and the data are used to set an upper limit on the MSSM parameter tan [beta] as a function of the mass of the pseudoscalar A boson in the range from 115 to 300 GeV. Furthermore, the model independent upper limits are given for the product of the cross section and branching fraction for gluon fusion and b quark associated production at √s = 8 TeV. As a result, they are the most stringent limits obtained to date in this channel.