Study of ambiguities in ${\pi }^{-}p\to \Lambda K^0$ scattering amplitudes

Abstract

Amplitudes for the reaction ${\pi }^{-}p\to \Lambda K^0$ are reconstructed from data on the differential cross section $d\sigma /d\Omega$, the recoil polarization $P$, and on the spin rotation parameter $\beta$. At low energies, no data on $\beta$ exist, resulting in ambiguities. An approximation using $S$ and $P$ waves leads only to a fair description of the data on $d\sigma /d\Omega$ and $P$; in this case, there are two sets of amplitudes. Including $D$ waves, the data on $d\sigma /d\Omega$ and $P$ are well reproduced by the fit but now, there are several distinct solutions which describe the data with identical precision. In the range where the spin rotation parameter $\beta$ was measured, a full and unambiguous reconstruction of the partial wave amplitudes is possible. The energy-independent amplitudes are compared to the energy dependent amplitudes which resulted from a coupled channel fit (BnGa2011-02) to a large data set including both pion and photo-induced reactions. Significant deviations are observed. Consistency between energy dependent and energy independent solutions by choosing the energy independent solution which is closest to the energy dependent solution. In a second step, the {\it known} energy dependent solution for low (or high) partial waves is imposed and only the high (or low) partial waves are fitted leading to smaller uncertainties.

References in corpus (2)

• Extended Partial-Wave Analysis of piN Scattering Data
• P-wave excited baryons from pion- and photo-induced hyperon production

Cited by in corpus (12)

• Photocouplings at the Pole from Pion Photoproduction
• Light Baryon Spectroscopy
• Strong evidence for nucleon resonances near 1900\,MeV
• Pole positions and residues from pion photoproduction using the Laurent+Pietarinen expansion method
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• Correlations of $\mathbf{\pi N}$ Partial Waves for Multi-Reaction Analyses
• Moravcsik's theorem on complete sets of polarization observables reexamined
• $K^0\Lambda$ and $D^{-}{\Lambda }_c^{+}$ production induced by pion beams off the nucleon
• Nucleon resonances in the ${\pi }^{-}p\to K^0\Lambda$ reaction near threshold
• Combined analysis of the ${\pi }^{-}p\to K^0\Lambda$, $\eta n$ reactions in a chiral quark model
• Complex phase structure of the meson-baryon $T$-matrix
• New graphical criterion for the selection of complete sets of polarization observables and its application to single-meson photoproduction as well as electroproduction