arXiv subjects

B. Zauner

Publications and source records attributed to B. Zauner.

21 records · Page 2Linked to original sources

arXiv2004

Nucleon resonances and processes involving strange particles

An existing single resonance model with S11, P11 and P13 Breit-Wiegner resonances in the s-channel has been re-applied to the old pi N --> K Lambda data. It has been shown that the standard set of resonant parameters fails to reproduce the shape of the differential cross section. The resonance parameter determination has been repeated retaining the most recent knowledge about the nucleon resonances. The extracted set of parameters has confirmed the need for the strong contribution of a P11(1710) resonance. The need for any significant contribution of the P13 resonance has been eliminated. Assuming that the Baker. et al data set\cite{Bak78} is a most reliable one, the P11 resonance can not but be quite narrow. It emerges as a good candidate for the non-strange counter partner of the established pentaquark anti-decuplet.

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arXiv2004

Presence of Extra P11 Resonances in Zagreb Analysis Since 1995

The partial wave T-matrices for the pi N, eta N and pi2 N channels have been obtained within the framework of the coupled channel model using the pi N elastic and pi N --> eta N data base as input. It has been shown that for the P11 partial wave an equally good representation of the experimental data (namely the T(pi N,pi N) and T(pi N,eta N) T-matrices) can be obtained using either three, or four poles for the Green function propagator. However, the three Green function pole solution is not acceptable due to the structure of the extracted resonances. The two out of four P11 resonances, those lying in the energy range 1700 MeV < MR < 1800 MeV, are poorly determined, but they seem to be strongly inelastic. The inclusion of other inelastic channels is needed to determine masses and widths of missing resonances with greater precision.

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arXiv2004

The detailed mechanism of the eta production in pp scattering up to the Tlab = 4.5 GeV

Contrary to very early beliefs, the experimental cross section data for the eta production in proton-proton scattering are well described if pi and only eta meson exchange diagrams are used to calculate the Born term. The inclusion of initial and final state interactions is done in the factorization approximation by using the inverse square of the Jost function. The two body Jost functions are obtained from the S matrices in the low energy effective range approximation. The danger of double counting in the p-eta final state interaction is discussed. It is shown that higher partial waves in meson-nucleon amplitudes do not contribute significantly bellow excess energy of Q=100 MeV. Known difficulties of reducing the multi resonance model to a single resonance one are illustrated.

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