What are the building blocks of correlation functions in CFT?

Primary fields are the fundamental building blocks of correlation functions in Two-Dimensional Conformal Field Theory (CFT). Correlation functions describe the statistical relationships between observables in a quantum field theory, and primary fields are the operators that create excitations in the theory. These fields play a central role in CFT, as they determine the behavior of correlation functions and encode information about the underlying symmetries and dynamics of the theory.