Search for the pentaquark resonance signature in lattice QCD

TL;DR

This study investigates the existence of the ^+ pentaquark resonance using lattice QCD, creating new interpolating fields and analyzing signals on a large lattice, ultimately finding no evidence for such a resonance in quenched QCD.

Contribution

The paper introduces a new candidate interpolating field for lattice QCD and provides a comprehensive analysis of pentaquark signals using improved actions on a large lattice.

Findings

No resonance signal observed for spin-1/2 pentaquark states.

Standard lattice resonance signals of attraction are absent.

Evidence supporting the ^+ pentaquark in quenched QCD is lacking.

Abstract

Claims concerning the possible discovery of the \Theta^+ pentaquark, with minimal quark content uudd\bar{s}, have motivated our comprehensive study into possible pentaquark states using lattice QCD. We review various pentaquark interpolating fields in the literature and create a new candidate ideal for lattice QCD simulations. Using these interpolating fields we attempt to isolate a signal for a five-quark resonance. Calculations are performed using improved actions on a large 20^3 x 40 lattice in the quenched approximation. The standard lattice resonance signal of increasing attraction between baryon constituents for increasing quark mass is not observed for spin-1/2 pentaquark states. We conclude that evidence supporting the existence of a spin-1/2 pentaquark resonance does not exist in quenched QCD.