QCD coupling constant below 1 GeV in the poincare-covariant model

Abstract

The behavior of the running coupling constant α s (Q 2) phenomenologically parameterized in the region of Q < 1 GeV is considered within the framework of the Poincare-covariant quark model in a variety of regimes. An analysis was carried out for pseudoscalar and vector mesons with the lepton masses and decay constants (obtained by the model calculations) required to match their experimental counterparts. It shows that the constant α s is likely to behave with αcrit = α s (Q 2 = 0) ∼ 0.667 − 0.821 in the case of a frozen regime and αcrit =0.300 − 0.692 for peaked curves, which follows from the experimental values of the leptonic decay constants and masses.