Quantum Chromodynamics (QCD) is a theory of the strong interaction between quark and gluons. Due to the strong interaction, quarks and gluons are quickly bounded into hadrons, the most common final states in high-energy collider. Precise prediction for their production is one of important topics in colliders to better understand the standard model and to accurately estimate background in new physics search.
In this talk, I will discuss challenges and improvement in our understanding of their productions, specifically focusing on quarkonium production, bound state of heavy quark and anti-quark pair, and on jet production, a group of energetic hadrons. At very low temperatures, neutrons form a strongly interaction quantum gas and this gas is a universal state appearing across different fields of physics including QCD and I will show an interesting phenomenon, a broken scale invariance in the gas predicted by using theoretical tool used for collider predictions.