The thrust of these phenomena can be calculated with soft-collinear effective theory, or SCET. For 10 points each:
[10m] Name these phenomena whose fragmentation is described by the Lund string model. These phenomena are created by hadronization and often follow parton showers.
ANSWER: particle jets [accept jet fragmentation]
[10h] In the expression for thrust in SCET, this function appears outside the integral. This function describes dynamics at a scale where the virtuality is roughly equal to the four-momentum.
ANSWER: hard part [or hard function, accept hard scale; prompt on H]
[10e] SCET was developed to suppress infrared divergences in this theory. This theory describes how the color charge of quarks and gluons gives rise to the strong force.
ANSWER: quantum chromodynamics [or QCD]
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