Lattice QCD study of antiheavy-antiheavy-light-light tetraquarks based on correlation functions with scattering interpolating operators both at the source and at the sink

TL;DR

This study uses lattice QCD with scattering operators to investigate the existence and properties of a stable antiheavy-antiheavy-light-light tetraquark, providing insights into its binding energy and quantum characteristics.

Contribution

It introduces a novel lattice QCD approach incorporating scattering operators at both source and sink to analyze tetraquark systems, focusing on the $ar b ar b u d$ state.

Findings

Ground state below meson-meson threshold

Binding energy extrapolated to infinite volume

Stable tetraquark candidate identified

Abstract

We present first results of a recently started lattice QCD investigation of antiheavy-antiheavy-light-light tetraquark systems including scattering interpolating operators in correlation functions both at the source and at the sink. In particular, we discuss the importance of such scattering interpolating operators for a precise computation of the low-lying energy levels. We focus on the $\bar b \bar b u d$ four-quark system with quantum numbers $I(J^P) = 0(1^+)$, which has a ground state below the lowest meson-meson threshold. We carry out a scattering analysis using L\"uscher's method to extrapolate the binding energy of the corresponding QCD-stable tetraquark to infinite spatial volume. Our calculation uses clover $u$, $d$ valence quarks and NRQCD $b$ valence quarks on gauge-link ensembles with HISQ sea quarks that were generated by the MILC collaboration.