Absence of evidence for pentaquarks on the lattice

TL;DR

This study uses lattice QCD with improved actions to investigate the existence of pentaquark states, finding no evidence for such resonances in the quenched approximation.

Contribution

It applies the correlation matrix method on lattice QCD to search for pentaquarks, providing a rigorous computational approach with high precision.

Findings

No evidence of pentaquark resonance in quenched QCD

Utilizes improved fixed point lattice action for accurate results

Analyzes ground and excited states in the isospin 0, negative parity channel

Abstract

We study the question of whether or not QCD predicts a pentaquark state. We use the improved, fixed point lattice QCD action which has very little sensitivity to the lattice spacing and also allows us to reach light quark masses. The analysis was performed on a single volume of size $(1.8 {\rm fm})^3\times 3.6 {\rm fm}$ with lattice spacing of $a=0.102$ fm. We use the correlation matrix method to identify the ground and excited states in the isospin 0, negative parity channel. In the quenched approximation where dynamical quark effects are omitted, we do not find any evidence for a pentaquark resonance in QCD.