APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Xiaojun Yao ( Massachusetts Institute of Technology)
Title: Quarkonium Transport in Quark-Gluon Plasma: Open Quantum System and Effective Field Theory
Date (JST): Wed, Jun 17, 2020, 10:00 - 11:00
Place: Zoom Seminar
Related File: 2540.pdf
Abstract: The production of heavy quarkonium in heavy ion collisions has been used as an important probe of the quark-gluon plasma. The initial insight was that due to the plasma screening effect, the color attraction between the heavy quark pair is significantly suppressed at high temperature and thus no bound states can exist, i.e., they “melt”. However, in addition to the screening effect, quarkonium dissociation induced dynamically and recombination are also crucial in phenomenology. Semiclassical transport equations that take into account these three physical processes have achieved great success in phenomenology.

In this talk, I will explain why the semiclassical transport equations can be used to describe the quarkonium evolution inside the quark-gluon plasma. I will start with the recent development in applying the open quantum system formalism to study quarkonium in-medium dynamics and show how to derive the semiclassical transport equation in this formalism by using potential nonrelativistic QCD, an effective field theory. Weak coupling and Markovian approximations used in the derivation can be justified from a separation of scales. Then I will introduce a set of coupled Boltzmann equations of open heavy flavors and quarkonia, which are motivated from the open quantum system studies. Finally I will show some phenomenological results on the Upsilon production that are based on the coupled Boltzmann equations.