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HK: Fachverband Hadronen und Kerne
HK 80: Hadron Structure and Spectroscopy I
HK 80.6: Talk
Friday, March 20, 2009, 12:15–12:30, H-ZO 20
pp→ΛΛ production cross section in a constituent quark model — •Pablo Garcia, David R. Entem, and Francisco Fernandez — Universidad de Salamanca, E-37008, Salamanca Spain
In recent years the interest in the NN system has been renewed due to the observation of a near threshold enhancement in the J/ψ→γ pp decay which was interpreted as a possible NN bound state or as a FSI effect in the NN system. Also the construction of the antiproton facility FAIR and its low energy facility FLAIR will provide new and precise data for reactions involving antiproton beams which motivates the theoretical study of such reactions.
In Ref. [1] a chiral constituent quark model was used to study the NN interaction. We now apply this model to study the ΛΛ production reaction. This reaction has been traditionally explained with kaon exchange in meson models and with gluon annihilation in quark models. The chiral constituent quark model used includes both mechanisms. The kaons are generated as pseudogoldstone bosons of the spontaneous chiral symmetry breaking and gluons as perturbative contributions from QCD.
We perform a coupled channel calculation which allows us to study the FSI and ISI approximations. The optical potential is modified to describe the pp total cross section data in the Λ Λ production energy range. We find that the kaon contribution dominates and we need to increase gch in the strange sector to describe the data. We also study polarization observables for the pp→ pp and pp→Λ Λ reactions.
[1] D.R. Entem, and F. Fernandez, Phys. Rev. C 73, 045214 (2006).