High-precision calculation of the strange nucleon electromagnetic form factors

• Main Authors: Green, Jeremy (Author), Meinel, Stefan (Author), Engelhardt, Michael (Author), Krieg, Stefan F. (Author), Laeuchli, Jesse (Author), Orginos, Kostas (Author), Pochinsky, Andrew (Contributor), Syritsyn, Sergey (Author), Negele, John W. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2015-09-01T14:19:21Z.
• Subjects: Article
• Online Access: Get fulltext

 We report a direct lattice QCD calculation of the strange nucleon electromagnetic form factors G[s over E] and G[s over M] in the kinematic range 0 ≤ Q[superscript 2] ≲ 1.2  GeV[superscript 2]. For the first time, both G[s over E] and G[s over M] 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.