Calculation and automation of one-loop corrections to 2 to 2 fermion processes

Complete perturbative one-loop quantum corrections for 2 to 2 fermion processes are presented. They are worked out within the electroweak standard model (EWSM) and quantum electrodynamics (QED) for typical linear collider energies. Special attention is drawn to the organization of a fully automatic calculation of differential and integrated cross sections, where all the masses are exactly treated and soft-photon radiation is also analytically included. The computational strategy and algorithms are outlined according to the operational mode of the programs. The first project in which I worked was an already existing Fortran program for top-quark production, Topfit, which has been upgraded by reconsidering the strategy and programming of the one-loop amplitudes. The extension to generic fermion species ff in the final state has been completed. On a technical level, numerical stabilization and improvement of performance was observed. The second project, aiTALC, has been fully developed as a Linux package designed to automate loop calculations in two-fermion scattering processes.ge with the purpose of evaluating the loop integrals numerically.on that, thanks to the Make environment, brings together the interoperability between the different modules. Finally, numerical applications are studied. For the final state fermion-pair we show production cross sections as well as angular distributions and asymmetries, predicted for the e+e- → tt, cc, bb, τ+τ- reactions within the EWSM. Bhabha scattering (e+e- → e+e-) is considered in more detail due to the increasing interest in supporting precise predictions for luminosity monitoring including necessarily the full electroweak corrections. Other interesting fermion processes with flavour changing neutral currents (e+e- → bs, tc) and Moeller scattering (e-e- → e-e-) are also presented