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

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.

10 pages, 7 eps-figures, invited talk at the 2nd ICTP International Conference on Perspectives in Hadronic Physics, Trieste, Italy, 10-14 May 1999