Quantum Chromodynamics 2026, 09 - Drell-Yan Process

Deep inelastic scattering experiments can show the internal structure of hadrons, if the reactions are hard. The process of quark-antiquark annihilation is the most similar to these experiments. It's called the Drell-Yan Process. Because the creation of quark-antiquark pairs works analogously with a time-reversed graph, this process can be used to understand hadron generation by dissociating quarks (p. 387). Drell-Yan cross sections depend partially on the Compton cross section q + G → γ* + q → μ⁺μ^- + q, which usually dominates. There are also complications associated with the infrared divergence, though its contributions will end up canceled by diverging radiative corrections as per Bloch-Nordsieck (391). The K-factor of the resummed QCD correction improves the agreement of the calculations with empirical data. It's always larger than 1, and primarily affects the total cross section R (405).

Calculations of elementary QCD processes in perturbations are calculated to quadratic order. Hardonizations are calculated using several specially developed computer codes, which function off basic assumptions about creation and decay of color strings between quarks, and finally one determines 3-jet events experimentally. There are no competing model to QCD at the time, so the specificity of QCD is unclear.