https://doi.org/10.1140/epjc/s10052-019-6560-7
Regular Article - Theoretical Physics
Remarks on the heavy-quark flavour symmetry for doubly heavy hadronic molecules
1
Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
2
Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218, Moscow, Russia
3
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninskiy Prospect 53, 119991, Moscow, Russia
4
Institut für Theoretische Physik II, Ruhr-Universität Bochum, 44780, Bochum, Germany
5
Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, 52425, Jülich, Germany
6
Tbilisi State University, 0186, Tbilisi, Georgia
7
Moscow Institute of Physics and Technology, 141700, Institutsky lane 9, Dolgoprudny, Moscow Region, Russia
8
National Research Nuclear University MEPhI, Kashirskoe highway 31, 115409, Moscow, Russia
* e-mail: nefediev@lebedev.ru
Received:
18
October
2018
Accepted:
31
December
2018
Published online:
21
January
2019
The possibility for a common effective field theory for hadronic molecules with different heavy-quark flavours is examined critically. It is argued that such a theory does not allow one to draw definite conclusions for doubly heavy molecules. In particular, it does not allow one to relate binding energies for the molecules in the c-quark and b-quark sectors with controlled uncertainties. Therefore, while this kind of reasoning does not preclude from employing heavy-quark spin symmetry for charmonium- and bottomonium-like states separately within a well established effective field theory framework, relations between different heavy-quark sectors can only be obtained using phenomenological approaches with uncontrolled uncertainties.
© The Author(s), 2019
