SINGLE TOP PRODUCTION AT NEXT-TO-NEXT-TO-LEADING ORDER IN QCD: AN ANALYTIC APPROACH

In this thesis, I study Next-to-Next-to-Leading order QCD corrections to one of the top quark production mode, the so-called Single Top production mechanism. In partic- ular I concentrate on Single Top production in t-channel in a 5-flavour scheme, where a bottom and a light quark exchange a W boson in t-channel thus producing a top quark, a light quark and, potentially, additional radiation. I first review the basics of Top Physics, with particular emphases on the status of the art of top quark production modes from both an experimental and theoretical point of view. I introduce then the general framework of perturbative QCD, and with that the main ingredients of computations at higher order in the \u3b1s expansion. In particular I focus on the description of Single Top in t-channel as a double Charged-Current Deep-Inelastic Scattering process, and illustrate how QCD corrections to this process are organized in this kind of picture. Thereafter I explain in detail the particular technique that I choose to use in my computation, the so-called Master Integrals technique. Finally, I present the original results achieved in the analytical computation of the QCD corrections at O(\u3b1s ^2) (NNLO) to the inclusive cross-section for Single Top in t-channel. In particular I present the determination and computation of the complete set of Master Integrals which describes the NNLO QCD corrections to massive Form Factors for CC-DIS. This set of Master Integrals is a milestone in the computation of NNLO QCD corrections to inclusive Single Top in t-channel and will make it possible to achieve a complete com- putation of these corrections in the next future