Participation in the DELPHI experiment at LEP collider of CERN

This dissertation presents the author's works he contributed with to the B hadron physics research in the frame of DELPHI collaboration, as well as, his recent studies in the field of supersymmetric particles carried out in the frame of MSSM with R-parity breaking. He also exposes planned studies as well as his technical contributions in the VFT (Very Forward Tracker) silicon detector project. New resonances are reported at the explored energies, namely for √s≅ 183 to 208 GeV. Upper bounds were derived for two couplings λ₁₂₁ and λ₁₃₁ of the order of a few 10^-3, breaking the R-parity at crossing the lepton number, when the sneutrino mass is very close to the COM energy available, irrespective of the tan β value and λ₁₂₁ and λ₁₃₁ couplings. These upper bounds are much accurate than those obtained via the precision indirect measurements. As shown on the curves giving the bounds as a function of sneutrino mass, it can be observed without being located on the resonance. This appears rather a promising process and it will be studied in the future by means of e⁺e^- linear collider or μ⁺μ^- collider, or even with a hadron collider (Tevatron and LHC). In conclusion the program exposed by the author is rich and diverse and probably will constitutes the basis of the future research on basic interaction for at least next 15 years. The contents of the Habilitation dissertation is as fallows: 1. Introduction; 2. Research on supersymmetric particles at DELPHI; 2.1. MSSM, R-parity and bachelor gauginos; 2.2. Studies of bachelor gauginos at √s = 183 to 208 GeV; 2.2.1. DELPHI; 2.2.2. Data batches; 2.2.3. Signal simulation; 2.2.4. Background generating processes; 2.2.5. Criteria of selection; 2.2.6. Results from real data processing; 2.2.7. Interpretation; 2.3. Conclusions; 3. Prospects; 3.1. B hadron decay; 3.2. Supersymmetries at LHC; 3.3. Conclusions; Appendix. VFT; 4.1. The significance of the review; 4.2. Data; 4.3. Analysis tools; 4.4. Results