Title :
Some topics in hadron spectroscopy

Speaker:
Stephen Lars Olsen, Seoul National University

Abstract :
Searches for hadronic states with a substructure that is more complex than 
the quark-antiquark mesons or three-quark baryons of the original quark model 
is a major focus of recent experimental and theorectical investigations on the 
area of hadron spectroscopy.   Curiously, some of the strongest candidates for 
non-quark-antiquark mesons – e.g., the a0(980) & f0(980) light scalar mesons, 
the X(3872) charmonium-like state, and the recently discovered Z1(10610)+ & Z2(10650)+ 
electrically charged bottomonium-like states – are all very close to meson-antimeson 
thresholds. The proximity of these thresholds can have important  influence on 
the way these particles decay, such as inducing anomalously large isospin violations, 
that may provide clues that help identify their underlying structure.  In this talk 
I will present some experimentally observed properties of non-quark-antiquark 
candidate states and discuss possible ways of characterizing their nature.