Tetraquark interpolating fields in a lattice QCD investigation of the Ds0∗ (2317) meson

Abstract

We investigate the Ds0∗(2317) meson using lattice QCD and considering correlation functions of several cs two-quark and cs(ūu+dd) four-quark interpolating fields. These interpolating fields generate different structures in color, spin and position space including quark-antiquark pairs, tetraquarks and two-meson scattering states. For our computation we use an ensemble simulated with pion mass mπ≈0.296 GeV and spatial volume of extent 2.90 fm. We find in addition to the expected spectrum of two-meson scattering states another state around 60 MeV below the DK threshold, which we interpret as the Ds0∗(2317) meson. This state couples predominantly to a quark-antiquark interpolating field and only weakly to a DK two-meson interpolating field. The coupling to the tetraquark interpolating fields is essentially 0, rendering a tetraquark interpretation of the Ds0∗(2317) meson rather unlikely. Moreover, we perform a scattering analysis using Lüscher's method and the effective range approximation to determine the Ds0∗(2317) mass for infinite spatial volume. We find this mass 51 MeV below the DK threshold, rather close to both our finite volume result and the experimentally observed value.