https://doi.org/10.1051/epjconf/201612900023
On properties of the exotic hadrons from QCD sum rules
1 Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna, Austria
2 D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow, Russia
3 Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
* e-mail: Wolfgang.Lucha@oeaw.ac.at
** e-mail: dmitri_melikhov@gmx.de
Published online: 25 November 2016
We discuss the specific features of extracting properties of the exotic polyquark hadrons (tetraquarks, pentaquarks) compared to the usual hadrons by the QCD sum-rule approach. In the case of the ordinary hadrons, already the one-loop leading-order O(α0s) correlation functions provide the bulk of the hadron observables, e.g., of the form factor; inclusion of radiative corrections O(αs) modifies already nonzero one-loop contributions. In the case of an exotic hadron, the situation is qualitatively different: discussing strong decays of an exotic tetraquark meson, which provide the main contribution to its width, we show that the disconnected leading-order diagrams are not related to the tetraquark properties. For a proper description of the tetraquark decay width, it is mandatory to calculate specific radiative corrections which generate the connected diagrams.
© The Authors, published by EDP Sciences, 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
