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SUMMARY:Extended quark models and QCD
DTSTART;VALUE=DATE-TIME:19980507T100000Z
DTEND;VALUE=DATE-TIME:19980507T110000Z
DTSTAMP;VALUE=DATE-TIME:20260617T173205Z
UID:indico-event-1073@indico.ific.uv.es
DESCRIPTION:In the talk the low energy effective action of QCD below the c
 hiral symmetry scale will be discussed\, including operators of higher dim
 ensions which can be built from quark fields and their derivatives\, witho
 ut or with additional chiral fields. The quark effective action prepared i
 n the QCD perturbation theory without explicit separation of chiral fields
  shares the features of the Nambu-Jona-Lasinio models being symmetric unde
 r chiral rotations but possessing the strong coupling constants which indu
 ce the dynamical creation of constituent quark mass and pions. The corresp
 onding effective meson lagrangian represents a generalization of the linea
 r sigma-model. The effective action which takes manifestly into account th
 e dynamical formation of nearly massless pions (chiral fields) represents 
 another way to describe the meson physics at low and intermediate energies
 . It starts from the chiral quark model and leads to a hybrid between the 
 latter one and the NJL like model. In both cases the crucial role plays th
 e matching to QCD with the help of requirement of chiral symmetry restorat
 ion at energies above the CSB scale. Qualitatively\, they bring a differen
 t CSB patterns: in the NJL approach the lightest scalar meson is a partner
  of the pion whereas in the Extended CQM the scalar meson becomes a partne
 r of the heavy pion (pi-prime meson). Two approaches will be compared in t
 he number of parameters derived from the meson phenomenology and in their 
 predictivity.\n\nhttps://indico.ific.uv.es/event/1073/
LOCATION:Dpto. de Fisica Teorica (UVEG) Sala Seminarios
URL:https://indico.ific.uv.es/event/1073/
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