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SUMMARY:Pion pion interactions and the size of the sigma meson
DTSTART;VALUE=DATE-TIME:20130312T110000Z
DTEND;VALUE=DATE-TIME:20130312T120000Z
DTSTAMP;VALUE=DATE-TIME:20260629T035329Z
UID:indico-event-1901@indico.ific.uv.es
DESCRIPTION:We explore the nature of the sigma meson by studying its size\
 , that we determine from its quadratic scalar radius. This is deduced from
  the scalar form factor\, that we calculate from SU(2) O(p^4) chiral lagra
 ngians\, without any ad-hoc free parameter\, given the dynamically generat
 ed nature of the sigma meson in the pion pion interactions. A small value 
 for the size of the sigma meson is found\, which points to a four-quark na
 ture of the latter\, rather than to a pion molecule picture. We also calcu
 late the dependence of the sigma meson pole and the quadratic scalar radiu
 s on the pion mass\, in order to give further meaning to our results. We a
 lso study pion pion interactions in a finite volume within two different f
 rameworks that implement chiral dynamics and unitarity\, namely\, the IAM 
 and the N/D method. We include in the chiral amplitudes the O(p^4) terms\,
  which are explicitly volume dependent\, in order to quantify the contribu
 tion of these terms\, that are exponentially supressed in Luscher's formal
 ism.\n\nhttps://indico.ific.uv.es/event/1901/
LOCATION:Edf. Institutos de Investigación Sala Seminarios IFIC
URL:https://indico.ific.uv.es/event/1901/
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