ar X iv : h ep - p h / 04 11 15 5 v 1 1 1 N ov 2 00 4 Testing the nature of the Λ ( 1520 ) resonance through photoproduction February 2 , 2008

Recent studies within the framework of chiral unitary theory produce the Λ(1520) resonance, among several others, as a dynamically generated resonance from the interaction of the baryon decuplet and the meson octet. The Λ(1520) qualifies as a quasibound state of πΣ(1385) and this has repercussion in some observable quantities. In the present work we show that the γp → K+K−p reaction has a sizeable cross section for invariantKpmasses above the Λ(1520) mass. On the other hand, we also find that the γp → K+πΣ(1385) reaction has a sizeable cross section in that energy region as a consequence of the strong coupling of the Λ(1520) to πΣ(1385), and then we make predictions for the ratio of this cross section to that of the γp → K+K−p reaction. The introduction of unitary techniques in the study of meson baryon interaction with chiral Lagrangians has allowed to show that many of the low lying baryonic resonances are dynamically generated in the implicit process of multiple scattering, or equivalently, they qualify as quasibound meson baryon states. Early studies in this direction pointed at the Λ(1405) [1] and the N(1535) [2] as dynamically generated resonances. The unitary methods to deal with the meson baryon interaction within the chiral framework have been made more systematic and a variety of them are now available, leading to remarkably similar results [3–11]. One of the consequences of these studies is that the interaction of the baryon octet and meson octet leads to two octets and one singlet of dynamically generated resonances with J = 1/2 [8, 11], to which the Λ(1405) and the N(1535) belong.