The Re-Analysis of the 1700 MeV Structure of the P 11 Partial Wave Using the πN → KΛ Production Data

Abstract

We have used the Breit-Wigner resonance model with S11, P11 and P13 resonances in the s-channel to re-analyze the old piN -> KLambda data with the aim to establish the origin of the prominent structure in the total cross section in the vicinity of 1700 MeV. In this paper we show that, at least in the Breit-Wigner resonance model, it is not possible to achieve the detailed reproduction of the narrow 1700 MeV total cross section peak using the standard partial widths. We have found the new set of resonance parameters enforcing the experimentally observed structure of the total cross section data simultaneously with the linear dependence of the differential cross sections with the cos(Theta) in the energy range 1650 MeV < W < 1800 MeV. The result is that the P13 partial wave has been strongly attenuated in this model. To understand the phenomenon, a much narrower width of a resonant state, the N(1710) P11 in our case, is required, but then the agreement of the model predictions with total cross section data at higher energies is lost. One way out is to allow for the existence of the second P11 resonance in that energy range. The same feature is shown by the polarization data. Analyzing the qqq or qqqq(qbar) nature of the recommended narrow P11 structure in the neighbourhood of 1700 MeV we re-open (remind of) the possibility that another P11 resonant state exists in addition to the standard N(1710) P11 PDG-resonance, and that one of the two states can be identified with the yet undiscovered cryptoexotic pentaquark state. To clarify the situation, we strongly recommend remeasurement of the piN -> KLambda process in the energy range 1650 MeV < W < 1800 MeV.