Eur. Phys. J. A (2020) 56: 61
https://doi.org/10.1140/epja/s10050-020-00057-4

Regular Article –Theoretical Physics

Hadron–Hadron interactions from lattice QCD: the -resonance

Extended Twisted Mass Collaboration

¹ Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, Bonn, Germany
² School of Physics and Center for High Energy Physics, Peking University, Beijing, China
³ Collaborative Innovation Center of Quantum Matter, Beijing, China
⁴ Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China

^* e-mail: urbach@hiskp.uni-bonn.de

Received: 4 July 2019
Accepted: 24 December 2019
Published online: 19 February 2020

Abstract

We present a lattice QCD investigation of the -meson with dynamical quark flavours for the first time. The calculation is performed based on gauge configuration ensembles produced by the ETM Collaboration with three lattice spacing values and pion masses ranging from 230 to 500 MeV. Applying the Lüscher method phase-shift curves are determined for all ensembles separately. Assuming a Breit–Wigner form, the -meson mass and width are determined by a fit to these phase-shift curves. Mass and width combined are then extrapolated to the chiral limit, while lattice artefacts are not detectable within our statistical uncertainties. For the -meson mass extrapolated to the physical point we find good agreement with experiment. The corresponding decay width differs by about two standard deviations from the experimental value.