The motivation for developing SCET was to control the infrared divergences that occur in quantum chromodynamics (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 (sprays of hadrons that emerge from particle collisions when a quark or gluon is produced). SCET has also been used to calculate electroweak interactions in Higgs boson production.