Infrared-suppressed QCD coupling and the hadronic contribution to muon g-2

Abstract

A variant of QCD with the coupling suppressed in the infrared (IR) regime, as suggested by large-volume lattice calculations of the Landau-gauge gluon and ghost dressing functions, is considered. The coupling is further restricted by the condition of approximate coincidence with perturbative QCD in the high momentum regime, and by the τ-lepton semihadronic decay rate in the intermediate momentum regime, the rate which is evaluated by a renormalon-motivated resummation method. The obtained coupling turns out to be free of Landau singularities. The D = 4, 6 condensate values of the Adler function are then extracted by application of the Borel sum rules to the OPAL and ALEPH (V+A)-channel data of τ-decay, and the corresponding V-channel condensate values are deduced as well. We then show that the correct value of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment, a had(1) µ , is reproduced by regularizing the D = 4, 6 OPE terms in the V-channel Adler function with IR-regularization masses M D/2 1 GeV, suggesting the internal consistency of the presented QCD framework.

Determination of perturbative QCD coupling from ALEPH $$\tau $$ decay data using pinched Borel–Laplace and Finite Energy Sum Rules

“…In the case of the sum rules (9), the timelike squared energy σ m is in an intermediate range σ m ∼ m 2 τ ∼ 1 GeV 2 (we have here σ m = 2.8 GeV 2 ). There exist several other timelike quantities in form of integrals of D(Q 2 ) that are phenomenologically important [41], among them: (a) the production ratio for e + e − → hadrons, R(s) [42,43], where the squared energy |Q 2 | = s > 0 is in principle not constrained; (b) the leading order hadronic vacuum polarisation contribution to the anomalous magnetic moment of μ lepton, (g μ /2 − 1) had (1) [ 45,46], where the dominant momenta [47,48].…”

“…This truncation means that we include in the expression (48) only the singular contributions. We note that for κ = 1 [κ = exp(− K )] the values of the residues d X p,k ( κ) reduce to the values d X p,k given in Eq.…”

Electron and muon magnetic moments and implications for dark matter and model characterisation in non-universal U(1)′ supersymmetric models

“…The SM prediction includes the electroweak, QED and hadronic components contributing to the muon g − 2. Despite large uncertainties arising from α S (M Z ) recent studies have significantly improved the calculations of the hadronic contributions [6][7][8]. The leading order (LO) contribution from the hadronic vacuum polarization (HVP) yields a HVP−LO,lattice µ = 707(55) × 10 −11 [9] using Lattice QCD, and comparison with JHEP10(2021)063 the e + e − → hadrons data indicates a deviation of about 1.6σ between the experimental measurements and theoretical calculations of the hadronic contributions to the muon g − 2 [10,11].…”

Electron and muon magnetic moments and implications for dark matter and model characterisation in non-universal $U(1)^\prime$ supersymmetric models

“…The SM prediction includes the electroweak, QED and hadronic components contributing to the muon g − 2. Despite large uncertainties arising from α S (M Z ) recent studies have significantly improved the calculations of the hadronic contributions [6][7][8]. The leading order (LO) contribution from the hadronic vacuum polarization (HVP) yields a HVP−LO,lattice µ = 707(55) × 10 −11 [9] using Lattice QCD, and comparison with the e + e − → hadrons data indicates a deviation of about 1.6σ between the experimental measurements and theoretical calculations of the hadronic contributions to the muon g − 2 [10,11].…”