High-precision calculation of the strange nucleon electromagnetic form factors

الأصل · EN

We report a direct lattice QCD calculation of the strange nucleon electromagnetic form factors Gₑˢ and Gₘˢ in the kinematic range 0 ≤ Q² 1.2 GeV². For the first time, both Gₑˢ and Gₘˢ are shown to be nonzero with high significance. This work uses closer-to-physical lattice parameters than previous calculations, and achieves an unprecedented statistical precision by implementing a recently proposed variance reduction technique called hierarchical probing. We perform model-independent fits of the form factor shapes using the z-expansion and determine the strange electric and magnetic radii and magnetic moment. We compare our results to parity-violating electron-proton scattering data and to other theoretical studies.