Perturbative Quantum Chromodynamics (pQCD) is a theoretical framework used to study interactions between quarks and gluons, the fundamental constituents of protons, neutrons, and other hadrons. In pQCD, these interactions are treated as a series of calculations that can be approximated through perturbation theory, allowing for the prediction of various observable quantities such as cross sections and decay rates. This approach is particularly useful for studying high-energy processes in particle physics, where the strong coupling between quarks and gluons can be treated perturbatively. By combining pQCD with experimental data, researchers can gain a deeper understanding of the strong nuclear force and test the predictions of the Standard Model of particle physics.