QCD result for the hyperfine splitting MΥ(1S)-Mηb and the value of αs
Abstract
The measurement of the ηb mass, together with a QCD result for the hyperfine splitting EHFS=MΥ(1S)-Mηb, allows us to determine the strong coupling constant αs at a low energy scale. The result αs(MΥ(1S))=0.197±0.002|ΔEHFSexp±0.002|scheme±0.002|δ⟨G2⟩±0.006|δmb±0.005|ho, αs(MZ0)=0.124±0.001|ΔEHFSexp±0.001|scheme±0.001|δ⟨G2⟩±0.003|δmb±0.002|ho is compatible with the current world average of αs reported by the Particle Data Group, and shows that the experimental lowest-lying b¯b hyperfine splitting can be reproduced in terms of a perturbative and nonperturbative QCD contribution.
- Publication:
-
Physical Review D
- Pub Date:
- January 2011
- DOI:
- 10.1103/PhysRevD.83.014016
- arXiv:
- arXiv:0912.1081
- Bibcode:
- 2011PhRvD..83a4016C
- Keywords:
-
- 14.40.Pq;
- 12.38.Qk;
- Experimental tests;
- High Energy Physics - Phenomenology
- E-Print:
- 9 pages, 3 figure. Analysis of the errors reconsidered, one figure added, title modified, accepted for publication in Phys. Rev. D