Abstract

We analyse the top-quark decay at the next-to-next-to-leading order (NNLO) in QCD by using the Principle of Maximum Conformality (PMC) which provides a systematic way to eliminate renormalization scheme and scale ambiguities in perturbative QCD predictions. The PMC renormalization scales of the coupling constant αs are determined by absorbing the non-conformal β terms that govern the behavior of the running coupling by using the Renormalization Group Equation (RGE). We obtain the PMC scale Q=15.5 GeV for the top-quark decay, which is an order of magnitude smaller than the conventional choice μr=mt, reflecting the small virtuality of the QCD dynamics of the top-quark decay process. Moreover, due to the non-conformal β terms disappear in the pQCD series, there is no renormalon divergence and the NLO QCD correction term is greatly increased while the NNLO QCD correction term is suppressed compared to the conventional results obtained at μr=mt. By further including the next-to-leading (NLO) electroweak corrections, the finite W boson width and the finite bottom quark mass, we obtain the top-quark total decay width Γttot=1.3112-0.0189+0.0190 GeV, where the error is the squared averages of the top-quark mass Δmt=±0.7 GeV, the coupling constant Δαs(MZ)=±0.0009 and the estimation of unknown higher-order terms using the PAA method with [N/M]=[1/1]. The PMC improved predictions for the top-quark decay are complementary to the previous PMC calculations for top-quark pair production and helpful for detailed studies of properties of the top-quark.

Details

Title
QCD improved top-quark decay at next-to-next-to-leading order
Author
Meng, Rui-Qing 1 ; Wang, Sheng-Quan 1 ; Sun, Ting 1 ; Luo, Chao-Qin 1 ; Shen, Jian-Ming 2 ; Wu, Xing-Gang 3 

 Guizhou Minzu University, Department of Physics, Guiyang, People’s Republic of China (GRID:grid.443389.1) (ISNI:0000 0000 9477 4541) 
 Hunan University, School of Physics and Electronics, Changsha, People’s Republic of China (GRID:grid.67293.39) 
 Chongqing University, Department of Physics, Chongqing Key Laboratory for Strongly Coupled Physics, Chongqing, People’s Republic of China (GRID:grid.190737.b) (ISNI:0000 0001 0154 0904) 
Pages
59
Publication year
2023
Publication date
Jan 2023
Publisher
Springer Nature B.V.
ISSN
14346044
e-ISSN
14346052
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2768578244
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.