Unexpectedly small empirical vector strangeness of nucleons realized in a baryon model

TL;DR

This paper reassesses baryon models predicting small or negligible strange vector form factors of nucleons, aligning theoretical expectations with recent precise measurements and lattice simulations showing minimal strangeness.

Contribution

It demonstrates that a baryon model based on the MIT bag with an instanton liquid can naturally produce very small nucleon strangeness, consistent with current experimental data.

Findings

Strange vector form factors are much smaller than previously thought.

Experimental uncertainties allow for zero strangeness within measurement errors.

The baryon model used aligns with recent empirical results.

Abstract

Most of model considerations of the hidden nucleon strangeness, as well as some preliminary experimental evidence, led to the expectations of relatively sizeable strange vector form factors of the proton. For example, it seemed that the contribution of the fluctuating strange quark-antiquark pairs accounts for as much as one tenth of the proton's magnetic moment. By the same token, baryon models which failed to produce the "vector strangeness" of the nucleon seemed disfavored. Recently, however, more accurate measurements and more sophisticated data analysis, as well as lattice simulations, revealed that the form factors associated with the vector strangeness of the nucleon are much smaller than thought previously; in fact, due to the experimental uncertainties, the measured strange vector-current proton form factors may be consistent with zero. In the light of that, we re-asses the merit of the baryon models leading to little or no vector strangeness of the nucleon. It is done on the concrete example of the baryon model which essentially amounts to the MIT bag enriched by the diluted instanton liquid.