Abstract:

In High Energy Physics, calculation of scattering cross section can be casted as series expansion over the strong coupling. Only the first term, i.e., the Leading Order (LO) term of such perturbation series is generally considered to be sufficient to study phenomenological aspects of a process of interest. However, when the necessity arises to compare theoretical prediction with the experimental outcome (say, from hadron colliders), we need to be more precise and therefore it becomes essential to consider next terms of such series which are of higher orders in strong coupling. The act of taking into account the immediate next term to the LO is known as Next-to-Leading Order (NLO) correction whose analytical calculation appears to be more involved compared to the LO. In this talk, I would focus on the techniques associated to the NLO calculation, describe the singularities that arise at intermediate steps and explain how to group together bits and pieces of them so that the complete NLO computation can be performed numerically.