@misc{10481/40873,
year = {2016},
url = {http://hdl.handle.net/10481/40873},
abstract = {In this thesis we make two investigations in the context of precision physics,
firstly in the multi-leg and secondly in the multi-loop frontier. In the first
part, we approach the problem of making automated NLO phenomenological
studies of gluon fusion driven Higgs production. Here we calculate the
R2 vertices necessary to use the effective theory of Higgs/gluon interactions
at one loop in MadGraph5 aMC@NLO for both a scalar and pseudoscalar
coupling. This has allowed for a study of the CP properties of the
Higgs/top-quark coupling where it is found that correlations between the
di-jet azimuthal angles in Higgs + 2 jets provide valuable CP information.
In the second part we work in the framework of the Four Dimensional Regularization
(FDR) approach, where we develop two-loop translation rules
between FDR and dimensional regularization in massless QCD in the form
of a coupling constant shift. To achieve this we set up a framework for
comparison between the two strategies and develop an algorithm for the
automation of the FDR defining expansion at two loops. During the investigation
we find that a naive global prescription in the scheme breaks
locality and universality in correlation functions with external fermions and
so we introduce a “sub-prescription” to deal with this. In this way we solve
a problem analogous to the breakdown of unitarity at two loops in the four
dimensional helicity method and provide explicit evidence of the consistency
of FDR at two loops. Furthermore we gain insight into the relation between
the FDR approach and a canonical counterterm picture, witnessing a direct
cancellation between FDR sub-vacua and counterterms.},
organization = {Tesis Univ. Granada. Departamento de Física Teórica y del Cosmos},
publisher = {Universidad de Granada},
keywords = {Alta energía},
keywords = {Correcciones radiativas},
keywords = {Aceleradores de haz colisor},
keywords = {Aceleradores de partículas},
keywords = {Gluones},
title = {Precision Physics in High Energy Colliders:  new techniques of calculating radiative corrections},
author = {Page, Benjamin John},
}