  We discuss how the lightest scalars, in particular the broad sigma resonance,
can be understood as unitarized (qbar q) states within a unitarized quark model
(UQM). The bare (qbar q) scalars are strongly distorted by hadronic mass
shifts, and the (ubar u+ dbar d) state becomes a very broad resonance, with its
pole at 470-i250 MeV. This is the sigma meson required by models for
spontaneous breaking of chiral symmetry. We also discuss the less well known
phenomenon that with a large coupling there can appear two physical resonance
poles on the second sheet although only one bare quark-antiquark state is put
in. The f_0(980) and f_0(1370) resonance poles can thus be two manifestations
of the same (sbar s) quark state. Both of these are dominant in the E791 Dalitz
plot of D_s-> 3pi, where (sbar s) intermediate states should be dominant.
Recently this light sigma has clearly been observed in D-> sigma pi-> 3pi by
the E791 experiment at Fermilab. We discuss how this decay channel can be
predicted in a Constituent Quark Meson Model (CQM), which incorporates heavy
quark and chiral symmetries.
