Strange nucleon form factors and isoscalar charges with $N_f=2+1$ $\mathcal{O}(a)$-improved Wilson fermions

TL;DR

This study calculates strange nucleon form factors and isoscalar charges using $N_f=2+1$ $ ext{O}(a)$-improved Wilson fermions, providing insights into their $Q^2$-dependence and renormalization.

Contribution

It presents a comprehensive lattice QCD analysis of strange and isoscalar nucleon form factors with improved techniques and a range of pion masses and lattice spacings.

Findings

Strange charge radii and magnetic moments determined.

Isoscalar axial and tensor charges analyzed.

Results span pion masses 200-360 MeV and lattice spacings 0.05-0.086 fm.

Abstract

We report on our calculation of the strange contribution to the vector and axial vector form factors. The strange charge radii, magnetic moment, and axial charge are extracted by model independent $z$-expansion fits to the $Q^2$-dependence of the respective form factors. Furthermore, the isoscalar contribution to the axial and tensor charge is investigated by combining the calculation of connected and disconnected diagrams. The required renormalization is performed with the Rome-Southampton method. We make use of the CLS $N_f=2+1$ $\mathcal{O}(a)$-improved Wilson fermion ensembles. Results are reported for pion masses in the range $m_\pi=200-360\,\text{MeV}$ and lattice spacings $a=0.05-0.086\,\text{fm}$.