Time & Place: May 24, Friday, 4:00 pm, Room 9409

Speaker: Prof. Wei Chen(陈伟), Sun Yat-sen University  （中山大学）

Title:  Petaquark and tetraquark states

Abstract: The past seventeen years have witnessed tremendous progress on
the experimental and theoretical explorations of the multiquark states.
Especially the LHCb collaboration not only confirmed the existence of
the hidden-charm pentaquarks but also provided strong evidence of the
molecular picture. Besides the well-known $XYZ$ and $P_c$ states, we
will discuss more interesting tetraquark and pentaquark systems either
with one, two, three or even four heavy quarks. Some very intriguing
states include the fully heavy exotic tetraquark states $QQ\bar Q\bar Q$
and doubly heavy tetraquark states $QQ\bar q\bar q$. The $QQ\bar Q\bar
Q$ states may be produced at LHC while the $QQ\bar q\bar q$ system may
be searched for at BelleII and LHCb. In the theoretical aspect, we will
emphasize the model-independent predictions of various models which are
truly/closely related to Quantum Chromodynamics (QCD). There have also
accumulated many lattice QCD simulations through multiple channel
scattering on the lattice in recent years, which provide deep insights
into the underlying structure/dynamics of the XYZ states.