Novel method for the precise determination of the QCD running coupling from event shape distributions in electron-positron annihilation
We present a novel method for precisely determining the running QCD coupling constant over a wide range of from event shapes for electron-positron annihilation measured at a single annihilation energy . The renormalization scale of the running coupling depends dynamically on the virtuality of the underlying quark and gluon subprocess and thus the specific kinematics of each event. The determination of the renormalization scale for event shape distributions is obtained by using the principle of maximum conformality (PMC), a rigorous scale-setting method for gauge theories which satisfies all the requirements of renormalization group invariance, including renormalization-scheme independence and consistency with Abelian theory in the limit. In this paper, we apply the PMC to two classic event shapes measured in annihilation: the thrust ( ) and C-parameter ( ). The PMC renormalization scale depends differentially on the values of and . The application of PMC scale-setting determines the running coupling to high precision over a wide range of from 10 to from measurements of the event shape distributions at the peak. The extrapolation of the running coupling using pQCD evolution gives the value from the thrust and from the C-parameter in the scheme. These determinations of are consistent with the world average and are more precise than the values obtained from analyses of event shapes currently used in the world average. The highly consistent results for the and event-shape distributions provide an additional verification of the applicability of the PMC to pQCD.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE; Natural Science Foundation of China
- Grant/Contract Number:
- AC02-76SF00515; SLAC-PUB-17458; 11625520; 11705033; 11847301; 11905056; KY[2016]028; KY[2017]067
- OSTI ID:
- 1573861
- Alternate ID(s):
- OSTI ID: 1596796
- Report Number(s):
- SLAC-PUB-17458; arXiv:1908.00060v2; PRVDAQ; 094010
- Journal Information:
- Physical Review D, Journal Name: Physical Review D Vol. 100 Journal Issue: 9; ISSN 2470-0010
- Publisher:
- American Physical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Muon and connection
Doubly virtual transition form factors in the light-front quark model