A Convergent Reformulation of QCD Perturbation Theory

por Dr. C.J. Maxwell (University of Durham)

jueves 17 jul. 1997 12:30 → 13:30 Europe/Madrid

Sala Seminarios (Dpto. de Fisica Teorica (UVEG))

We propose a generalization of Grunberg's effective charge idea in which in addition to the effective charge describing a QCD observable R(Q), we introduce an infinite set of additional effective charges, each one describing the sub-asymptotic Q-dependence of the preceding one. The resulting reformulation of perturbative QCD gives a set of manifestly RS-invariant approximations which converge to a limit equal to the Borel sum of the conventional asymptotic perturbation series in alpha_s(mu^2) , with remaining ambiguities due to infra-red renormalons. There are close connections with Pade approximation.