Comparison of Lattice Coulomb Gauge Wave Functions in Quenched Approximation and with Dynamical Fermions

TL;DR

This study compares Coulomb gauge wave functions from quenched and dynamical fermion lattice QCD simulations, analyzing particle sizes and neutron charge radius, finding minimal differences between the two approaches.

Contribution

It provides parameterizations of wave functions for spectroscopy and compares particle sizes and charge radii in quenched and dynamical fermion simulations.

Findings

Particle sizes are approximately half of physical states.

Neutron charge radius ratio matches experimental values.

No significant differences between quenched and dynamical simulations.

Abstract

We present a comparison of Coulomb gauge wave functions from $6/{g^2}=6.0$ quenched simulations with two simulations which include the effects of dynamical fermions: simulations with two flavors of dynamical staggered quarks and valence Wilson quarks at $6/{g^2}=5.6$ and simulations with two flavors of dynamical Wilson quarks and Wilson valence quarks, at $6/{g^2}=5.3$. The spectroscopy of these systems is essentially identical. Parameterizations of the wave functions are presented which can be used as interpolating fields for spectroscopy calculations. The sizes of particles are calculated using these parameterized wave functions. The resulting sizes are small, approximately half the sizes of the physical states. The charge radius of the neutron, which provides an indication of the asymmetries between the wave functions of up and down quarks, is calculated. Although the size of the nucleon in these simulations is small, the ratio of the charge radius of the neutron to that of the proton is consistent with the physical value. We find no significant differences between the quenched and dynamical simulations.