On the Structure of the Lambda 1405

TL;DR

This paper clarifies the structure of the Lambda 1405 resonance, demonstrating it is primarily a bound anti-kaon--nucleon state through lattice QCD and Hamiltonian analysis, resolving a long-standing mystery.

Contribution

It introduces a Hamiltonian effective field theory and volume dependence analysis that confirm the anti-kaon--nucleon dominance in Lambda 1405's structure.

Findings

Strange magnetic form factor of Lambda 1405 vanishes

Lambda 1405 is dominated by anti-kaon--nucleon component

Volume dependence supports infinite volume limit connection

Abstract

For almost 50 years the structure of the Lambda 1405 resonance has been a mystery. Recently, a new lattice QCD simulation showing that its strange magnetic form factor vanishes, together with a comprehensive Hamiltonian analysis of the lattice QCD energy levels, has unambiguously established that the structure is dominated by a bound anti-kaon--nucleon component [1]. Here we present supplementary information for Ref. [1] including a presentation of the relevant Hamiltonian effective field theory and an illustration of the volume dependence of the results and their connection to the infinite volume limit of Nature.