Thursday, 20 January 2005 - h. 15:00 

Auditorium B. Touschek

  L. Maiani
 (U. Roma, La Sapienza)

"Scalar mesons, new narrow states with charm, and exotic charmonium states: the begining of a new spectroscopy ?" 


The properties of the scalar mesons a(980) and f(980) do not fit the usual quark-antiquark picture. The recent confirmation of sigma(480) and kappa(800), at FermiLab and Frascati, supports the idea that these mesons are diquark - antidiquark bound states. This would signal the existence of a new spectroscopy, which is particularly interesting in the cases when one or more light quarks are replaced by heavy quarks. Belle (KEK) and BaBar (SLAC), have recently observed few charmonium states, like X(3872) that also do not fit the usual scheme and that we propose to be diquark-antidiquark states.
I will discuss the light mesons and then illustrate the interesting properties one can predict for the heavy states, with particular attention to the case of the X(3872).


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MCD, 14/1/05