Friday 6 December, 11:00h, at Nikhef in H331
Speaker: Soeren Lange (Giessen University)
Title: “Observation of new particle states with the Belle experiment”
Abstract:
Observations of new charmonium(-like) and bottomonium(-like) states (sometimes refered to as "XYZ" states) at e+e- colliders have changed our picture of quarkonia systems as QCD bound states. Potential models, which were able to predict many conventional states with an accuracy of ~1 MeV, absolutely fail in describing many of the new states. Some of the new narrow states even seem to be charged, therefore cannot represent conventional quarkonium and may be discussed as states of possibly exotic nature (e.g. molecules, tetraquarks, hybrids). Recent results will be presented, with emphasis on the Belle experiment. At the end, an outlook to the upgrade project Belle II will be given.
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