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arXiv · 2102.04973

Isospin-1/2 $D\pi$ scattering and the lightest $D_0^\ast$ resonance from lattice QCD

Luke Gayer·Nicolas Lang·Sinéad M. Ryan·David Tims·Christopher E. Thomas·David J. Wilson
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Abstract

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 and hence enable us to map out the energy dependence of elastic $D\pi$ scattering. By analytically continuing a range of scattering amplitudes, a $D_0^\ast$ resonance pole is consistently found 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.

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Luke Gayer, Nicolas Lang, Sinéad M. Ryan, David Tims, Christopher E. Thomas, David J. Wilson. 2021-02-09. Isospin-1/2 $D\pi$ scattering and the lightest $D_0^\ast$ resonance from lattice QCD. https://doi.org/10.1007/jhep07(2021)123

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