München 2009 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 12: QCD (Theorie) 2
T 12.4: Vortrag
Dienstag, 10. März 2009, 17:30–17:45, M109
Heavy Quark Vacuum Polarization Function at O(alpha**2(s)) O(alpha**3(s)) — •Vicent Mateu1, Andre Hoang1, and Seyyed Mohammad Zebarjad2 — 1MPI Munich — 2Shiraz University
We determine the full mass and q^2 dependence of the heavy quark vacuum polarization function at O(alpha_s^2) and O(alpha_s^3) in perturbative QCD. We use known results for the expansions at high energies, in the threshold region and around q^2=0, conformal mapping and the Pade approximation method. From our results we determine numerically the previously unknown non-logarithmic contributions in the high-energy expansion at order (m^2/q^2)^i for i=0,1 and the coefficients in the expansion around q^2=0 at order q^{2n} with n > 1. We also determine the previously unknown O(v^0) constant term for the expansion in the threshold region. We use these results to perform an analysis of QCD sum rules to determine the charm and bottom quark masses, in the context of contour improved perturbation theory. In This method gives additional insight into the estimate of perturbative uncertainties.