We study light scalar mesons with particular focus on the a_0(980) using lattice QCD with 2+1+1 dynamical quark flavors. To investigate the structure of these scalar mesons and to identify, whether a sizeable tetraquark component is present, we use a large set of operators, including diquark-antidiquark, mesonic molecule and two-meson operators. We find that the low-lying states overlap essentially exclusively with two-meson states. This indicates that in the channels investigated no tightly bound four-quark states of either molecular or diquark-antidiquark type exist.
@article{arxiv.1302.3389,
title = {Scalar mesons and tetraquarks from twisted mass lattice QCD},
author = {Marc Wagner and Constantia Alexandrou and Jan Oliver Daldrop and Mattia Dalla Brida and Mario Gravina and Luigi Scorzato and Carsten Urbach and Christian Wiese},
journal= {arXiv preprint arXiv:1302.3389},
year = {2013}
}
Comments
6 pages, 1 figure, talk given at "Excited QCD 2013", February 3-9 2013, Bjelasnica Mountain, Sarajevo, Bosnia