https://doi.org/10.1140/epjc/s10052-016-4438-5
Regular Article - Theoretical Physics
QCD sum rule study of hidden-charm pentaquarks
1
School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing, 100191, China
2
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
3
School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
4
Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou, 730000, China
5
School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, 100871, China
6
Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
7
Center of High Energy Physics, Peking University, Beijing, 100871, China
* e-mail: wec053@mail.usask.ca
Received:
18
September
2016
Accepted:
10
October
2016
Published online:
24
October
2016
We study the mass spectra of hidden-charm pentaquarks having spin 
and quark contents 
. We systematically construct all the relevant local hidden-charm pentaquark currents, and we select some of them to perform QCD sum rule analyses. We find that the 
and 
can be identified as hidden-charm pentaquark states composed of an anti-charmed meson and a charmed baryon. Besides them, we also find (a) the lowest-lying hidden-charm pentaquark state of 
has the mass 
GeV, while the one of 
is significantly higher, that is, around 4.7–4.9 GeV; (b) the lowest-lying hidden-charm pentaquark state of 
has the mass 
GeV, consistent with the of , while the one of 
is also significantly higher, that is, above 4.6 GeV; (c) the hidden-charm pentaquark state of 
has a mass around 4.5–4.6 GeV, slightly larger than the of 
.
© The Author(s), 2016
