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Renata Jora

Syracuse University
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Model for light scalars in QCD

We consider a generalized linear sigma model with two
chiral nonets, one with a quark-antiquark structure,
the other one with "diquark-diantiquark"
structure. The model aims to explain the existence of
a lighter than 1 GeV nonet of scalar mesons.
We investigate in this context the masses and mixings
of the pseudoscalar and scalar states and find that
the lightest pseudoscalar mesons have a large two
quark content and the lightest scalar mesons have a
large four quark content. The pion-pion scattering is
also studied in the limit of massless quarks and for
an SU(3) invariant symmetry breaking term. While the
current algebra results hold for the first case, they
no longer verify for the latter one.

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