Properties of the Resonance Lambda(1520) as seen in the Forward Electroproduction at JLab Hall A

TL;DR

This study measures the properties of the Lambda(1520) resonance in electroproduction experiments at JLab, providing precise mass and width values, and estimating the pole position for the first time, highlighting the sensitivity to background assumptions.

Contribution

It offers the first estimation of the Lambda(1520) pole position and analyzes how background parametrizations affect resonance parameter extraction.

Findings

Resonance mass M=1520.4 MeV with uncertainties

Width Gamma=18.6 MeV with uncertainties

Pole position estimates are smaller than Breit-Wigner values

Abstract

High-resolution spectrometer measurements of the reaction H(e,e' K+)X at small Q2 are used to extract the mass and width of the Lambda(1520). We investigate dependence of the resonance parameters on different parametrizations of the background and the resonance peak itself. Our final values for the Breit-Wigner parameters are M=1520.4+-0.6(stat)+-1.5(syst) MeV and Gamma=18.6+-1.9(stat)+-1(syst) MeV. The width appears to be more sensitive to the assumptions than the mass. We also estimate, for the first time, the pole position for this resonance and find that both the pole mass and width seem to be smaller than their Breit-Wigner values.