https://doi.org/10.1140/epjc/s10052-019-7531-8
Regular Article - Theoretical Physics
Study of the dilepton electromagnetic decays of 
Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
* e-mail: thwang@hit.edu.cn
Received:
6
October
2019
Accepted:
29
November
2019
Published online:
10
December
2019
In this paper, the dilepton electromagnetic decays 
and 
, where 
denotes 
, 
and 
, are calculated systematically in the improved Bethe–Salpeter method. The numerical results of decay widths and the invariant mass distributions of the final lepton pairs are given. The comparison is made with the recently measured experimental data of BESIII. It is shown that for the cases including 
, the gauge invariance is decisive and should be considered carefully. For the processes of , the branching fraction are: 
, 
, and 
. The calculated branching fractions of 
channels are: 
, 
, and 
.
© The Author(s), 2019
