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Quarkonium: New Developments

Chris Quigg
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Abstract

To illustrate the campaign to understand heavy quarkonium systems, I focus on a puzzling new state, $X(3872) \to π^+π^- J/ψ$. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium spectroscopy: additional discrete charmonium levels that can be discovered as narrow resonances of charmed and anticharmed mesons. I recall some expectations for a new spectroscopy of mesons with beauty and charm, the $B_c$ ($b\bar{c}$) system. Throughout, I call attention to open issues for theory and experiment.

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Chris Quigg. 2004-04-22. Quarkonium: New Developments. https://arxiv.org/abs/hep-ph/0403187

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