An introduction to the quark model
An introduction to the quark model
An introduction to the quark model
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Few-charge systems His<strong>to</strong>ry of <strong>the</strong> <strong>quark</strong> <strong>model</strong> Mesons Baryons Multi<strong>quark</strong>s and o<strong>the</strong>r exotics Outlook<br />
Improvements: loop corrections<br />
¯D (∗)<br />
(c¯c) (c¯c)<br />
D (∗)<br />
Provide <strong>the</strong> state above threshold a width,<br />
Can be calculated using <strong>the</strong> 3 P0 <strong>model</strong>, and an overall of initial<br />
and final wave functions<br />
Give a mass-shift (dispersive part)<br />
One expects many cancellations. For instance, if D = D ∗ , all 3 PJ<br />
states receive <strong>the</strong> same shift. But if D ∗ > D, <strong>the</strong>n differential shift<br />
in addition, thus mimicking spin-orbit and tensor forces.<br />
Should be more pronounced near a threshold,<br />
see below ψ ′ − η ′ c<br />
If <strong>to</strong>o large an effect, back <strong>to</strong> <strong>the</strong> bootstrap?<br />
¯c<br />
c<br />
JMR Quark Model<br />
q<br />
¯q<br />
¯c<br />
c