Time & Place: Sep. 13 (Thursday), 10:00am, Room 9409

Title: “Quark-Gluon Plasma” at the Smallest Scales

Speaker: Dr. Zhenyu Chen, Stonybrook University, US


 Abstract: In ultra-relativistic collisions of large, heavy nuclei
 (e.g. Au or Pb), a new state of nuclear matter consisting of liberated
 quarks and gluons is formed at a temperature of trillion Kelvins,
commonly referred to as Quark Gluon Plasma (QGP). The QGP was found to
exhibit collective behavior and flow as a nearly “perfect” fluid. The
elementary collision systems such as proton-proton (pp) or
proton-nucleus (pA), which were thought to be too small and dilute to
form a QGP, were treated as references in understanding the perfect
fluidity in large heavy ion systems. Surprisingly, Recent years,
evidence for collective effects has been revealed in pp and pPb
collisions when looking at events releasing large number of particles.
The experimental observations lead to a debate of the formation of QGP
in those small collision systems. In this talk, I will go over key
findings related to the possible QGP formation in pp and pA systems.
Their implications to the paradigm of heavy ion physics, as well as
future opportunities, will also be discussed.