Determination of αs\alpha_s and heavy quark masses from recent measurements of R(s)R(s)

Sep, 2001
15 pages
Published in:
  • Nucl.Phys.B 619 (2001) 588-602,
  • Nucl.Phys.B 640 (2002) 415-415 (erratum)
e-Print:
Report number:
  • DESY-01-130,
  • TTP-01-21

Citations per year

2001200720132019202305101520
Abstract: (Elsevier)
In this paper we compare recent experimental data for the total cross section σ ( e + e − →hadrons) with the up-to-date theoretical prediction of perturbative QCD for those energies where perturbation theory is reliable. The excellent agreement suggests the determination of the strong coupling α s from the measurements in the continuum. The precise data from the charm threshold region, when combined with the recent evaluation of moments with three loop accurracy, lead to a direct determination of the short distance MS charm quark mass. Our result for the strong coupling constant α s (4) (5 GeV)=0.235 +0.047 −0.047 corresponds to α s (5) ( M Z )=0.124 +0.011 −0.014 , for the charmed quark mass we find m c ( m c )=1.304(27). Applying the same approach to the bottom quark we obtain m b ( m b )=4.209(50) GeV. Whereas our result for α s ( M Z ) serves as a useful cross check for other more precise determinations, our values for the charm and bottom quark masses are more accurate than other recent analyses.
  • 12.38.-t
  • 14.65.Dw
  • 14.65.Fy
  • electron positron: annihilation
  • hadron: electroproduction
  • cross section: hadronic
  • energy dependence
  • quantum chromodynamics: perturbation theory
  • strong interaction: coupling constant
  • charm