A new resonance in K+Lambda electroproduction: the D_{13}(1895) and its electromagnetic form factors

TL;DR

This paper identifies a new resonance in K+Lambda electroproduction at around 1895 MeV, explaining a structure in the cross section and extracting its electromagnetic form factors using recent experimental data.

Contribution

It introduces a new D13 resonance at 1895 MeV in K+Lambda electroproduction and demonstrates how polarization measurements can reveal its properties.

Findings

Resonance at 1895 MeV explains the cross section structure.

Electromagnetic form factors of the resonance are extracted.

Polarization observables provide additional resonance information.

Abstract

New SAPHIR p(gamma,K+)Lambda total cross section data show a resonance structure at a total c.m. energy around 1900 MeV. We investigate this feature with an isobar model and find that the structure can be well explained by including a new D_{13} resonance at 1895 MeV. Such a state has been predicted by a relativistic quark model at 1960 MeV with significant gamma-N and K-Lambda branching ratios. We demonstrate how the measurement of single and double polarization observables can be used to obtain additional information on this resonance. Using recent (e,e'K+) JLab data from Hall C we extract the electromagnetic form factors of this state.