We present the nucleon strange electromagnetic form factors using four lattice QCD ensembles with Nf=2+1+1 twisted mass clover-improved fermions and quark masses tuned to approximately their physical values. The four ensembles have similar physical volume and lattice spacings of a=0.080 fm, 0.068 fm, 0.057 fm and 0.049 fm allowing us to take the continuum limit directly at the physical pion mass point. We compute nucleon three-point correlation functions with high statistics, where the disconnected fermion loops are evaluated stochastically with spin-color dilution and hierarchical probing. We find non-zero values for both electric and magnetic form factors. We extract the strange electric and magnetic radii, as well as the strange magnetic moment in the continuum limit by studying the momentum dependence of the form factors. We also compute the charm electromagnetic form factors within the same setup, which we find to be consistent with zero within the statistical precision of our data.
@article{arxiv.2603.26591,
title = {Nucleon strange electromagnetic form factors from $N_f=2+1+1$ lattice QCD},
author = {Constantia Alexandrou and Simone Bacchio and Mathis Bode and Jacob Finkenrath and Andreas Herten and Christos Iona and Giannis Koutsou and Ferenc Pittler and Bhavna Prasad and Gregoris Spanoudes},
journal= {arXiv preprint arXiv:2603.26591},
year = {2026}
}