Nearly perturbative lattice-motivated QCD coupling with zero IR limit

Ayala C, Cvetic G, Kögerler R, Kondrashuk I. Nearly perturbative lattice-motivated QCD coupling with zero IR limit. Journal of Physics G: Nuclear and Particle Physics. 2018;45(3): 035001.The product of the gluon dressing function and the square of the ghost dressing function in the Landau gauge can be regarded to represent, apart from the inverse power corrections 1/Q^{2n}, a nonperturbative generalization A(Q^2) of the perturbative QCD running coupling a(Q^2)=alpha_s(Q^2)/pi. Recent large volume lattice calculations for these dressing functions strongly indicate that such a generalized coupling goes to zero as A(Q^2)~Q^2 when the squared momenta Q^2 go to zero (Q^2<