QCD Sum Rules study of meson-baryon sigma terms

TL;DR

This paper uses QCD sum rules to calculate meson-baryon sigma terms and strange-quark condensates, providing precise ratios with minimal parameter dependence, and discusses implications for nucleon and Delta strangeness content.

Contribution

It introduces a Monte Carlo-based analysis of QCD sum rules for sigma terms, improving uncertainty estimates and ratio accuracy compared to previous methods.

Findings

High-accuracy sigma term ratios with minimal QCD parameter dependence

Quantitative estimates of strangeness content in nucleons and Deltas

Systematic uncertainty analysis using Monte Carlo methods

Abstract

The pion-baryon sigma terms and the strange-quark condensates of the octet and the decuplet baryons are calculated by employing the method of quantum chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition matrix elements of two baryon interpolating fields in an external isoscalar-scalar field and use a Monte Carlo-based approach to systematically analyze the sum rules and the uncertainties in the results. We extract the ratios of the sigma terms, which have rather high accuracy and minimal dependence on QCD parameters. We discuss the sources of uncertainties and comment on possible strangeness content of the nucleon and the Delta.