COLORTTH · The Higgs: A colored View from the Top at ATLAS

With the ground-breaking discovery of a new, Higgs-like boson on July 4th, 2012, by the CMS and ATLAS collaborations at CERN, a new era of particle physics has begun. The discovery is the first step in answering an unsolved problem in particle physics, the question how fundamental bosons and fermions acquire their mass. One of the major goals in collider physics in the next few years will be the deeper insight into the nature of the new particle, its connection to the known fundamental particles and possible extensions beyond the standard model (SM) of particle physics.My project aims at a particular interesting field to study, the relation of the new particle with the heaviest known elementary particle, the top quark. I aim to develop new, innovative techniques and beyond state-of-the-art methods to extract the Yukawa coupling between the top quark and the Higgs boson, which is expected to be of the order of one - much higher than that of any other quark. I will analyse the only process where the top-Higgs Yukawa coupling can be measured, in associated production of top quark pairs and a Higgs boson. The Higgs boson mainly decays into a pair of b-quarks. This is one of the most challenging channels at the LHC, as huge background processes from gluon splitting contribute. In particular, I will develop and study color flow variables, which provide a unique, powerful technique to distinguish color singlet Higgs bosons from the main background, color octet gluons.The ultimate goal of the project is the first measurement of the top-Higgs Yukawa coupling and its confrontation with SM and beyond SM Higgs boson models, resulting in an unprecedented insight into the fundamental laws of nature.The LHC will soon reach a new energy frontier of 13 TeV starting in 2014. This new environment will provide never seen opportunities to study hints of new physics and precisely measure properties of the newly found particle. This sets the stage for the project.""