Updated determination of $N^*$ resonance parameters using a unitary, multichannel formalism

Abstract

Results are presented for an updated multichannel energy-dependent partial-wave analysis of $\pi N$ scattering. Our earlier work incorporated single-energy amplitudes for $\pi N \rightarrow \pi N$, $\gamma N \rightarrow \pi N$, $\pi N \rightarrow \pi\pi N$, $\pi N \rightarrow \eta N$, and $\pi N \rightarrow K \Lambda$. The present work incorporates new single-energy solutions for $\gamma p \rightarrow \eta p$ up to a c.m.\ energy of 1990~MeV, $\gamma p \rightarrow K^+ \Lambda$ up to a c.m.\ energy of 2230~MeV, and $\gamma n \rightarrow \eta n$ up to a c.m.\ energy of 1885~MeV, as well as updated single-energy solutions for $\pi N \rightarrow \eta N$, $\pi N \rightarrow K \Lambda$, and $\gamma N \rightarrow \pi N$. In this paper, we present and discuss the resonance parameters obtained from a combined fit of all these single-energy amplitudes. Our determined energy-dependent amplitudes provide an excellent description of the corresponding measured observables.