Soft Collinear Effective Theory

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In quantum field theory, soft-collinear effective theory (or SCET) is a theoretical framework for doing calculations in quantum chromodynamics (QCD) that involve interacting particles carrying widely different energies. The motivation for developing SCET was to control the infrared divergences that occur in QCD calculations that involve particles that are soft -- carrying much lower energy or momentum than other particles in the process -- or collinear -- traveling in the same direction as another particle in the process. SCET is an effective theory for highly energetic quarks interacting with collinear and/or soft gluons. It has been used for calculations of the decays of B mesons (quark-antiquark bound states involving a bottom quark) and the properties of jets.