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.
The motivation for creating SCET was to address infrared divergences in quantum chromodynamics (QCD) calculations involving particles that are either soft—carrying low energy or momentum—or collinear—traveling in the same direction as other particles. SCET is a theoretical approach suitable for highly energetic quarks interacting with gluons that share similar characteristics.