Poszukiwanie bozonow Higgsa w akceleratorach LEP i LHC. A search for the Higgs bosons with LEP and LHC colliders

This thesis contains two analyzes which are contributions to experimental studies onthe Higgs sector in physics of fundamental interactions.The first one was performed using the data collected by the DELPHI detector at theelectron-positron collider LEP at CERN. This analysis is a search for the Higgs bosonwithin generalized non-minimal Higgs sector. It is based on the high number of b-quarksamong products of decays of Higgs boson.The analysis was performed using the data collected with energies near the Z 0 boson mass(LEP1 data) corresponding to an integrated luminosity of L = 71.4 pb −1 and the datacollected with highest energies of the LEP accelerator (LEP2 data) i.e. at the center-ofmass energies 189−208 GeV corresponding to an integrated luminosity of L = 611.2 pb −1 .It allowed to obtain the limits on production cross-sections of the neutral Higgs bosondecaying into final states with b-quarks.This analysis is a part of a project aiming at the exploitation of the DELPHI data forHiggs bosons search within the generalized non-minimal Higgs sector models.The second analysis is a study on the possibility of measurement of CP parity of theHiggs boson using the data which will be collected by the CMS detector. This detectorshould start to operate at the proton-proton collider LHC in the year 2007. This study isbased on samples obtained with the Monte Carlo technique using algorithms for triggerand events reconstruction which will be used by the real experiment.In the CMS data angle correlations in Φ → ZZ → 2e2µ process (,,golden channel” for Higgsboson searches in LHC) were studied. A precision of future measurement of parameterdescribing a ΦZZ coupling which determines CP -parity of the Higgs boson was evaluatedon this analysis.