Search for b ¯ b ¯ us and b ¯ c ¯ ud tetraquark bound states using lattice QCD

Abstract

We use lattice QCD to investigate the existence of strong-interaction-stable antiheavy-Antiheavy-light-light tetraquarks. We study the b¯b¯us system with quantum numbers JP=1+ as well as the b¯c¯ud systems with quantum numbers I(JP)=0(0+) and I(JP)=0(1+). We carry out computations on five gauge-link ensembles with 2+1 flavors of domain-wall fermions, including one at the physical pion mass. The bottom quarks are implemented using lattice nonrelativistic QCD, and the charm quarks using an anisotropic clover action. In addition to local diquark-Antidiquark and local meson-meson interpolating operators, we include nonlocal meson-meson operators at the sink, which facilitates the reliable determination of the low-lying energy levels. We find clear evidence for the existence of a strong-interaction-stable b¯b¯us tetraquark with binding energy (-86±22±10) MeV and mass (10609±22±10) MeV. For the b¯c¯ud systems we do not find any indication for the existence of bound states, but cannot rule out their existence either. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.