Isospin-1/2 DπD\pi scattering and the lightest D0∗D_0^\ast resonance from lattice QCD

Isospin-1/2 $D\pi$ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately $(3.6\; \mathrm{fm})^3$ and with a light quark mass corresponding to $m_\pi\approx239$ MeV. The spectrum of the elastic $D\pi$ energy region is computed yielding 20 energy levels. Using the L\"uscher finite-volume quantisation condition these energies are translated into constraints on the infinite volume scattering amplitudes. For the first time, we find a complex $D_0^\ast$ resonance pole from lattice QCD, strongly coupled to the $S$-wave $D\pi$ channel, with a mass $m\approx 2200$ MeV and a width $\Gamma\approx400$ MeV. Combined with earlier work investigating the $D_{s0}^\ast$, and $D_0^\ast$ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the $D_0^\ast$ is consistently found well below that of the $D_{s0}^\ast$, in contrast to the currently reported experimental result.Comment: 39 pages, 13 figure

Isospin-1/2 Dπ scattering and the lightest D 0 ∗ resonance from lattice QCD

Abstract: Isospin-1/2 Dπ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately (3.6 fm)3 and with a light quark mass corresponding to mπ ≈ 239 MeV. The spectrum of the elastic Dπ energy region is computed yielding 20 energy levels. Using the Lüscher finite-volume quantisation condition, these energies are translated into constraints on the infinite-volume scattering amplitudes and hence enable us to map out the energy dependence of elastic Dπ scattering. By analytically continuing a range of scattering amplitudes, a D0∗ resonance pole is consistently found strongly coupled to the S-wave Dπ channel, with a mass m ≈ 2200 MeV and a width Γ ≈ 400 MeV. Combined with earlier work investigating the Ds0∗, and D0∗ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the D0∗ is consistently found well below that of the Ds0∗, in contrast to the currently reported experimental result