Properties of the Lambda(1405) Measured at CLAS

TL;DR

This paper reports high-statistics measurements of the Lambda(1405) baryon’s lineshape and production cross sections at Jefferson Lab, providing insights into its complex structure and dynamical components.

Contribution

It presents the first detailed experimental measurement of the Lambda(1405) lineshape and differential cross sections across multiple decay channels.

Findings

Lambda(1405) lineshape measured with high precision

Differential cross sections for Lambda(1405), Sigma(1385), and Lambda(1520) obtained

Results suggest complex dynamical structure of Lambda(1405)

Abstract

The nature of the Lambda(1405), and its place in the baryon spectrum has remained uncertain for decades. Theoretical studies have shown that it may possess strong dynamical components which are not seen in other well-known baryons. Using the CLAS detector system in Hall B at Jefferson Lab, we have measured the photoproduction reaction gamma+p->K+ Lambda(1405) with high statistics and over different Sigma pi decay channels. The reconstructed invariant mass distribution (lineshape) has been measured, as well as the differential cross sections for the Lambda(1405), Sigma(1385), and Lambda(1520). Our analysis method is discussed and our near-final results for the Lambda(1405) lineshape and differential cross section are presented.