scholarly journals Drell-Yan Cross Section to Third Order in the Strong Coupling Constant

2020 ◽  
Vol 125 (17) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger
Keyword(s):  
Strong Coupling ◽  
Cross Section ◽  
Strong Coupling Constant ◽  
Coupling Constant ◽  
Third Order

scholarly journals RESUMMATION ANALYSIS OF THE τ-DECAY WIDTH USING THE FOUR-LOOP β-FUNCTION

1998 ◽  
Vol 13 (08) ◽  
pp. 637-649 ◽  
Author(s):  
S. GROOTE ◽  
J. G. KÖRNER ◽  
A. A. PIVOVAROV
Keyword(s):  
Strong Coupling ◽  
Decay Width ◽  
Fourth Order ◽  
Perturbation Series ◽  
Strong Coupling Constant ◽  
Coupling Constant ◽  
Convergence Radius ◽  
Third Order ◽  
Order Analysis ◽  
Β Function

We extract the strong coupling constant [Formula: see text] from the semileptonic τ-decay width taking into account resummation effects from the running of the strong coupling constant. In the [Formula: see text] scheme. The result reads αs=0.375±0.007 to third-order and αs=0.378±0.007 to fourth-order in the β-function, respectively, where we use the recently computed four-loop coefficient β3. These values for the coupling constant have to be compared with the value αs=0.354±0.005 derived from a third-order analysis of τ-decays. We determine the exact value of the convergence radius of the perturbation series by analyzing the singularity structure of the complex coupling constant plane.

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