https://doi.org/10.1140/epjc/s10052-019-7158-9
Regular Article - Theoretical Physics
The 
leptonic decay using the principle of maximum conformality
1
Department of Physics, Chongqing University, Chongqing, 401331, People’s Republic of China
2
School of Physics and Electronics, Hunan University, Changsha, 410082, People’s Republic of China
* e-mail: wuxg@cqu.edu.cn
Received:
20
May
2019
Accepted:
18
July
2019
Published online:
7
August
2019
In the paper, we study the leptonic decay width 
by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, 
keV, where the error is squared average of those from 
, 
GeV and the choices of factorization scales within 
of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.
© The Author(s), 2019
