6533b86dfe1ef96bd12c95e2
RESEARCH PRODUCT
τ hadronic spectral function moments in a nonpower QCD perturbation theory
Irinel CapriniGauhar AbbasJan FischerB. Ananthanarayansubject
PhysicsQuantum chromodynamicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHadronPerturbation (astronomy)Conformal map01 natural sciencesSeries accelerationstrong coupling0103 physical sciencesCentre for High Energy PhysicsPerturbation theory (quantum mechanics)010306 general physicsReference modeltau decaysLeptondescription
Abstract The moments of the hadronic spectral functions are of interest for the extraction of the strong coupling and other QCD parameters from the hadronic decays of the τ lepton. We consider the perturbative behavior of these moments in the framework of a QCD nonpower perturbation theory, defined by the technique of series acceleration by conformal mappings, which simultaneously implements renormalization-group summation and has a tame large-order behavior. Two recently proposed models of the Adler function are employed to generate the higher order coefficients of the perturbation series and to predict the exact values of the moments, required for testing the properties of the perturbative expansions. We show that the contour-improved nonpower perturbation theories and the renormalization-group-summed nonpower perturbation theories have very good convergence properties for a large class of moments of the so-called “reference model”, including moments that are poorly described by the standard expansions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-04-01 | Nuclear and Particle Physics Proceedings |