2015
Exotic states of matter: Have we finally found the 4-quark and 5-quark states ?, Dr Peter Kim (SLAC)
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Pacific/Honolulu
112 (Watanabe)
112
Watanabe
Description
Quantum chromodynamics (QCD) in the Standard Model is a pure gauge field theory of the Strong Nuclear Force. QCD has been successful in describing the Strong Interaction processes at different energy scales all the way up to 1 TeV at the LHC. However, our understanding of the QCD's role in nucleons (protons and neutrons) where the quark model and QCD were conceived in the first place is rather poor due to the inapplicability of perturbative calculations. Recent progress in non-perturbative QCD, notably Lattice QCD, promises to enlighten us on the nature of QCD at the fundamental level.
QCD predicts exotic states (glueballs, hybrids, multi-quark states) beyond the nominal 3-quark and quark-antiquark combinations of baryons and mesons. Searches for these exotic states for the last 40 years have been unfruitful until the hints of 4-quarks states, namely X Y Z state, were first observed by the Belle experiment. We will present a review of latest status of the X Y Z states and the recent claim of a pentaquark state by the LHCb experiment, and their implications on the QCD theory of confinement and spectroscopy.
This talk is intended to be accessible to UH physicists in all subfields.