DSpace@MIT

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 193-203).Introduction: Over the centuries we have been studying the world around us, discovering new physics at new length scales. Starting from our everyday experience which ranges from scales of about 10[superscript 3] to 10[superscript -3] meters (m), we encounter phenomena like gravity, contact forces, fluid dynamics and light. When we move on to the smaller scales of cells at 10[superscript -5] m or molecules and atoms around 10[superscript -10] m, we pass entire fields of science such as biology and chemistry. It is surprising that the underlying physics that leads to this rich variety of phenomena is simply (quantum) electrodynamics. The nucleus of the atom at scales of 10[superscript -15] m is made of protons and neutrons and is held together by the nuclear force. This is a residual force coming from the strong force, also known as Quantum Chromodynamics (QCD). QCD is responsible for confining the quarks to protons and neutrons. The remaining force that is part of the well established Standard Model of particle physics is the weak force, which for example plays a role in some hadron decays. With the Large Hadron Collider (LHC) at CERN starting to take data, we will be probing nature at smaller length scales than before and hope to discover new physics. In order to reconstruct new short distance physics from the measured leptons and QCD radiation, one typically looks for a signal with a certain number of jets of energetic hadrons. This thesis explores the effect of such restrictions on the hadronic final state in theoretical calculations, with an emphasis on the 0-jet case which allows us to study initial-state radiation. An introduction to the work in this thesis can be found in the next section ...