Nucleon strangeness form factors from N_f=2+1 clover fermion lattice QCD

TL;DR

This paper reports a lattice QCD calculation of nucleon strangeness form factors using N_f=2+1 clover fermions, achieving results consistent with experiments and reducing uncertainties significantly.

Contribution

It introduces an improved stochastic method and multiple source technique to enhance the precision of nucleon strangeness form factor calculations in lattice QCD.

Findings

The strange magnetic form factor at zero momentum transfer is measured as G_M^s(0) = -0.017(25)(07).

The results are consistent with experimental measurements.

The method reduces uncertainties compared to previous lattice calculations.

Abstract

We present the N_f=2+1 clover fermion lattice QCD calculation of the nucleon strangeness form factors. We evaluate disconnected insertions using the Z(4) stochastic method, along with unbiased subtractions from the hopping parameter expansion. We find that increasing the number of nucleon sources for each configuration improves the signal significantly. We obtain G_M^s(0) = -0.017(25)(07), where the first error is statistical, and the second is the uncertainties in Q^2 and chiral extrapolations. This is consistent with experimental values, and has an order of magnitude smaller error.