Singlet baryons in the graded symmetry approach to partially quenched QCD

TL;DR

This paper extends the graded symmetry approach to partially quenched QCD by including flavor-singlet baryons, enabling better estimation of sea-quark loop contributions in lattice QCD calculations of baryon properties.

Contribution

It introduces a formalism that explicitly incorporates flavor-singlet baryons and their interactions, improving the analysis of sea-quark effects in lattice QCD.

Findings

Formalism includes octet and singlet baryons and ghost counterparts.

Application to Lambda(1405) baryon as a case study.

Facilitates separation of sea-quark loop contributions.

Abstract

Progress in the calculation of the electromagnetic properties of baryon excitations in lattice QCD is presenting new challenges in the determination of sea-quark loop contributions to matrix elements. A reliable estimation of the sea-quark loop contributions presents a pressing issue in the accurate comparison of lattice QCD results with experiment. In this article, an extension of the graded symmetry approach to partially quenched QCD is presented, which builds on previous theory by explicitly including flavor-singlet baryons in its construction. The formalism takes into account the interactions among both octet and singlet baryons, octet mesons, and their ghost counterparts; the latter enables the isolation of the quark-flow disconnected sea-quark loop contributions. The introduction of the flavor-singlet states anticipates the application of the method to baryon excitations such as the lowest-lying odd-parity Lambda baryon, the Lambda(1405), which is considered in detail as a worked example.