https://doi.org/10.1140/epjc/s10052-025-14247-1
Regular Article - Theoretical Physics
Investigation of box diagrams for the peak of
in
and
1
College of Physics and Engineering, Qufu Normal University, 273165, Qufu, China
2
School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
3
Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, 516000, Huizhou, Guangdong, China
a
gli@qfnu.edu.cn
b
wujiajun@ucas.ac.cn
Received:
17
March
2025
Accepted:
28
April
2025
Published online:
8
May
2025
The BESIII Collaboration recently observed a charged hidden-charm structure with strangeness in the recoil mass spectrum of in the processes
or
, named as
. Within the energy region around the peak of
, various box diagrams are present. A systematic study of these box diagrams reveals the existence of a box singularity. Dalitz plots and invariant mass distributions of two charmed mesons from the box diagram for the processes
and
are presented at five energy points
, and 4.698 GeV. It is found that these box diagrams can generate peaks similar to those observed in experiments, suggesting that the peak of
may be attributed to the box singularity contribution. Additionally, slight differences in the invariant mass spectra of
and
are identified based on the box diagrams, needing further experimental validation.
© The Author(s) 2025
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