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The sigma and f_0(980) from Ke4 + pi-pi scatterings data
Mennessier G., Narison S., Wang X.-G.
Physics Letters B 688, 1 (2010) 59-66 - http://hal.archives-ouvertes.fr/hal-00457346
Physique/Physique des Hautes Energies - Phénoménologie
Physique/Physique des Hautes Energies - Expérience
Physique/Physique des Hautes Energies - Réseau
Physique/Physique Nucléaire Théorique
The sigma and f_0(980) from Ke4 + pi-pi scatterings data
Gerard Mennessier ()1, Stephan Narison ()1, X. -G. Wang
1 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
CNRS : UMR5207 – IN2P3 – Université Montpellier II - Sciences et techniques
Bât 13- 1er Et. - CC 070 Place Eugène Bataillon 34095 MONTPELLIER CEDEX 5
We systematically reconsider, within an improved "analytic K-matrix model", the extraction of the sigma = f_0(600) and f_0(980) masses, widths and hadronic couplings using new Ke4 = K-->pi-pi e nu_e data on pi-pi phase shift below 390 MeV and different sets of pi-pi--> pi-pi / K-K scatterings data from 400 MeV to 1.4 GeV. Our results are summarized in Tables 1, 2 and 5. In units of MeV, the complex poles are: M_sigma=452(12) - i 260(15) and M_f=981(34) -i 18(11), which are comparable with some recent high-precision determinations and with PDG values. Besides some other results, we find: |g_{sigma K+K-}|/|g_{sigma pi+pi-}|=0.37(6) which confirms a sizeable g_{sigma K+K-} coupling found earlier, and which disfavours a large pi-pi molecule or four-quark component of the sigma, while its broad pi-pi width (relative to the one of the rho-meson) cannot be explained within a \bar qq scenario. The narrow pi-pi width of the f_0(980) and the large value: |g_{f K+K-}|/|g_{f pi+pi-}|=2.59(1.34), excludes its pure (\bar uu+\bar dd) content. A significant gluonium component eventually mixed with \bar qq appears to be necessary for evading the previous difficulties.

Physics Letters B (Phys. Lett. B)
Publisher Elsevier
ISSN 0370-2693 
Articles dans des revues avec comité de lecture

Meson properties – Meson–meson interactions – S-matrix – Non-perturbative calculations

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