2014/11/28 by Y. Sumino, Sumino, Y.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1411.7853
openalex publication_date 2014/11/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This lecture note presents a self-contained introduction to the theory of a heavy quark-antiquark (QQ) system in terms of perturbative QCD. The lecture is intended for non-experts, such as graduate course students. The heavy QQ system serves as an ideal laboratory for testing various aspects of QCD: We can examine the nature of renormalons in perturbative series; an effective field theory Potential-NRQCD is constructed, whose derivation from full QCD can be traced stepwise; we see absorption of renormalons by non-perturbative matrix elements in OPE clearly; a systematic short-distance expansion of UV contributions can be performed, which predicts a "Coulomb+linear" potential in perturbative QCD; we can test these theoretical formulations by comparison to lattice computations, where we observe a significant overlap with perturbative regime; finally we can test our microscopic understanding by comparing to experimental data for the bottomonium states. These subjects are covered in a concise and elementary manner. Overall, we provide a microscopic description of the main dynamics of a heavy QQ system, as an example for which theoretical framework, practical computations and qualitative understanding have been most advanced.