New extended interpolating operators for hadron correlation functions

TL;DR

This paper introduces new extended interpolating operators for lattice QCD that improve overlap with hadron states and enhance short-distance behavior, with tunable fermion mass and good renormalisation properties.

Contribution

The paper presents a novel class of extended operators made of quenched 3D fermions, offering better control, renormalisation, and short-distance behavior in lattice QCD calculations.

Findings

Operators show improved short-distance behavior.

Numerical tests compare favorably with point and smeared sources.

Operators are easy to control in the continuum limit.

Abstract

New extended interpolating operators made of quenched three dimensional fermions are introduced in the context of lattice QCD. The mass of the 3D fermions can be tuned in a controlled way to find a better overlap of the extended operators with the states of interest. The extended operators have good renormalisation properties and are easy to control when taking the continuum limit. Moreover the short distance behaviour of the two point functions built from these operators is greatly improved. The operators have been numerically implemented and a comparison to point sources and Jacobi smeared sources has been performed on the new CLS configurations.