Threshold Resummation in Pair Production

Abstract

In performing perturbative calculations in Quantum Chromodynamics, large logarithmic corrections can arise from processes involving soft and collinear quanta. These corrections can be resummed to all orders, allowing us to improve our control over cross section calculations associated with exclusive and inclusive processes. In this thesis, we show how such logarithmic corrections can appear in perturbative calculations in Quantum Chromodynamics. We then proceed to apply these resummation methods at next-to-leading logarithmic accuracy to heavy quark pair production and light hadron pair production. We show how to incorporate consistently cuts in rapidity and transverse momentum of the observed particles, together with resummation. This allows us to compare our next-to-leading logarithmic calculations directly to experiments by placing the precise experimental cuts associated with the measurements of these processes. We will also examine the phenomenological features associated with the logarithmic corrections. Specifically, we will look how we can apply this to the study jet mass distributions.We will compare jet mass distribution from jets initiated from light quarks to those initiated by top quarks. This will then allow us to build jet shape observables that will let us distinguish between the two.