Electroproduction of $\Lambda$(1405)

TL;DR

This study investigates the electroproduction of the $ ext{Lambda}$(1405) resonance at Jefferson Lab, revealing a line shape variation with momentum transfer that supports a two-pole meson-baryon model over traditional resonance parameters.

Contribution

It provides the first detailed analysis of the $ ext{Lambda}$(1405) electroproduction line shape dependence on $Q^2$, supporting a two-pole meson-baryon interpretation.

Findings

Line shape varies with $Q^2$

Supports two-pole meson-baryon model

Deviates from PDG resonance parameters

Abstract

The electroproduction of $K^+ \Lambda$ (1405) was studied by analyzing the E1F data set collected in Hall B at Jefferson Lab. The analysis utilized the decay channel $\Sigma^+ \pi^-$ of the $\Lambda$ (1405) and $p \pi^0$ of the $\Sigma^+$. Simulations of background, $\Lambda$ (1405) and $\Lambda$ (1520) production according to PDG values were performed by using standard CLAS analysis tools adapted for the E1F run. Fits of the acceptance-corrected simulations were made to the acceptance-corrected data to determine contributions from signal and background processes. The line shape of $\Lambda$ (1405) varies with the four momentum transfer, $Q^2$, and does not match the line shape based on PDG resonance parameters. It corresponds approximately to predictions of a recent two-pole meson-baryon picture of this state.