Ref HAL: hal-00653509_v1
Ref Arxiv: 1108.3501
DOI: 10.1103/PhysRevD.85.014005
WoS: WOS:000298925900001
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
24 Citations
Résumé:

A recent extension of a variationally optimized perturbation, combined with renormalization group properties in a straightforward way, can provide approximations to nonperturbative quantities such as the chiral symmetry breaking order parameters typically. We apply this to evaluate, up to third order in this modified perturbation, the ratio Fpi/Lambda, where Fpi is the pion decay constant and Lambda the basic QCD scale in the modified MS scheme. Using experimental Fpi input value we obtain Lambda(nf=2) ~ 255_{-15}^{+40} MeV, where quoted errors are estimates of theoretical uncertainties of the method. This compares reasonably well with some recent lattice simulation results. We briefly discuss prospects (and obstacles) for extrapolation to alpha_S(mu) at perturbative mu values.

Commentaires: 5 pages