https://doi.org/10.1140/epjc/s10052-018-6387-7
Regular Article - Theoretical Physics
The ratio 
and the D-meson distribution amplitude
1
College of Physics and Materials Science, Henan Normal University, Xinxiang, 453007, People’s Republic of China
2
Department of Physics, Chongqing University, Chongqing, 401331, People’s Republic of China
3
School of Science, Guizhou Minzu University, Guiyang, 550025, People’s Republic of China
4
Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing, 100049, People’s Republic of China
* e-mail: zhongtao@htu.edu.cn
Received:
24
August
2018
Accepted:
27
October
2018
Published online:
14
November
2018
In this paper, we calculate the 
transition form factors (TFFs) within the light-cone sum rules (LCSRs) and predict the ratio . More accurate D-meson distribution amplitudes (DAs) are essential to get a more accurate theoretical prediction. We construct a new model for the twist-3 DAs 
and 
based on the QCD sum rules under the background field theory for their moments as we have done for constructing the leading-twist DA 
. As an application, we observe that the twist-3 contributions are sizable in whole 
-region. Taking the twist-2 and twist-3 DAs into consideration, we obtain 
. As a combination of the Lattice QCD and the QCD LCSR predictions on the TFFs 
, we predict 
, which is about 
deviation from the HFAG average of the Belle and BABAR data. At present the data still have large errors, and we need further accurate measurements of the experiment to confirm whether there is a signal of new physics from the ratio .
© The Author(s), 2018
